gardener maintaining park in dubai sunshine — Photo by Iftehkar Hussain Raufi

Workplace heat protections: a review of legislative and union action across eleven jurisdictions

Research by Hugi Hernandez, Founder of Egreenews

Introduction

As global temperatures continue to rise, the threat of extreme heat in the workplace has moved from a seasonal inconvenience to a year-round occupational health crisis. For outdoor workers, kitchen staff, and factory employees, prolonged exposure to high temperatures can lead to heat exhaustion, heat stroke, and even death. Despite these well-documented risks, the patchwork of state and local policies across the United States and Canada remains inconsistent, leaving millions of workers unprotected. This report reviews the current understanding and actions of state legislators, city mayors, and workers’ unions regarding workplace heat protections across eleven distinct jurisdictions: Montreal, Toronto, San Juan, Hawaii, San Francisco, Montgomery, Tallahassee, New York City, Chicago, and Atlanta.

Outdoor construction workers face heat-related fatality rates 13 times higher than average. A 2022 University of Washington study found Washington state construction workers had the second-highest risk of heat-related death, after agriculture.

The evidence, drawn exclusively from peer-reviewed academic literature published between 2016 and 2026, indicates that while technical knowledge of heat-health risks is often present among city-level officials, effective action is frequently blocked by state preemption laws or diluted by concerns over economic competitiveness. Workers’ unions have emerged as critical advocates for protective policies, yet their influence varies significantly by region. This analysis provides a sober, data-driven assessment of where progress has been made, where resistance remains entrenched, and what gaps persist in our understanding of how elected officials and labor organizations perceive this growing threat.

Part 1: The health case for workplace heat protections

The human health toll of occupational heat exposure is substantial and disproportionately borne by outdoor workers. A comprehensive 2022 study on Washington state’s outdoor workers found that agricultural workers had a yearly average heat-related fatality rate of 3.1 per 1,000,000 workers and the highest risk of heat-related deaths compared to all other industries, with a rate ratio of 35.2 (95% confidence interval 26.3–47.0). Construction workers had the second highest risk, with a rate ratio of 13.0 (95% confidence interval 10.1–16.7) [38†L33-L44]. These statistics underscore that working outside is not merely uncomfortable; it is demonstrably dangerous.

Agricultural workers face the highest risk of heat-related death—35 times higher than workers in other industries. Despite this, few U.S. states have enforceable outdoor heat standards for farmworkers.

For indoor workers, the risks are equally concerning. A 2020 study of New York City public school kitchens conducted by the Bard Graduate Center and the University of Illinois at Chicago found that 80% of kitchens sampled exceeded the recommended action limit for heavy work-rate scenarios, and 30% exceeded the threshold limit value [40†L12-L21]. The study concluded that kitchen staff in NYC public schools may be exposed to excessive indoor heat levels, with inadequate work-rest schedules posing serious risks of heat-related illness and acute injury [40†L21-L28]. Factory workers face similar threats: research from the University of Chicago’s Energy Policy Institute found that for every one degree Celsius rise in annual temperature, manufacturing plants generate about two percent less revenue, primarily due to reduced worker productivity and increased absenteeism on hot days [41†L4-L10]. The study demonstrated that heat stress is an important underlying cause for declines in non-agricultural gross domestic product during high-temperature years [41†L20-L27].

A 2025 review published in Current Environmental Health Reports synthesizing research on extreme heat and agricultural workers in Canada and the United States concluded that extreme heat presents a widespread and urgent threat to the wellbeing and productivity of agricultural workers globally, amplifying occupational exposures such as pesticides and air pollution [43†L6-L12]. The same review noted that laws designed to protect workers from extreme heat are limited to a handful of jurisdictions in both countries, and more research is needed to understand how effective existing laws are at protecting workers on the ground [43†L12-L19]. This evidence gap is itself a critical finding: despite the severity of the threat, systematic evaluation of policy effectiveness remains sparse.

Key finding No. 1: The health risks of occupational heat exposure are well-documented across outdoor, kitchen, and factory settings, with agricultural workers facing a heat-related death risk 35 times higher than workers in other industries.

Part 2: State legislators and the preemption problem

Among state legislatures, understanding of workplace heat risks varies dramatically, and action often diverges sharply from awareness. The most significant structural barrier to progress in the United States has been the passage of state preemption laws that forbid local governments from enacting their own heat safety standards. Florida and Texas have been the most aggressive in this regard.

“The general legal provisions on heat at work are to be fleshed out via social dialogue… Analysis of all relevant labor agreements reveals that these do seldom give proper guidance in managing heat at work. Most importantly, hardly any of these collective agreements contain a clear, science-based threshold for working in heat.”

In Florida, a 2024 analysis of the Sunshine State’s approach found that despite facing frequent high-heat days, the state has no legal right to basic heat protection like water, rest, and shade for outdoor workers [11†L6-L10]. In April 2024, Governor Ron DeSantis signed House Bill 433, a broad preemption law that blocks local municipalities from enacting heat stress protections for outdoor workers, as well as predictive scheduling laws and living wage standards [46†L22-L27]. The law specifically prohibits any city or county from establishing workplace heat-exposure requirements not mandated by state or federal law [3†L9-L11]. Miami-Dade County had been actively considering a landmark heat safety ordinance that would have granted outdoor workers the right to a ten-minute rest in the shade for every two hours worked when the heat index rose above 90 degrees Fahrenheit [29†L41-L47]. That effort was effectively killed by the state preemption law.

Texas has taken a similar path. A 2023 analysis from the University of Houston’s Hobby School of Public Affairs noted that Governor Greg Abbott signed House Bill 2127 into law, which removes protections for workers’ rights to regular water breaks [4†L8-L12]. The bill preempts local ordinances that go beyond state law, effectively blocking cities like Austin and Dallas from enacting stronger heat protections for outdoor workers. Neither Florida nor Texas has adopted a statewide heat standard for outdoor workers, and no state in the Southeastern United States—where workplace heat deaths are most common—has created its own heat safety rules [15†L23-L26].

California presents a contrasting case. The state’s 2005 outdoor heat standard, which requires employers to provide water, shade, and rest breaks when temperatures exceed 80°F, has been associated with significant reductions in heat-related deaths. A 2025 study from George Washington University and Middlebury College examined California’s policy and found that while there was no decline during initial implementation (2005–2009), estimated reductions reached 33 percent after enforcement increased (2010–2014) and 51 percent after policy revisions (2015–2020) [42†L16-L22]. The study concluded that when properly designed and enforced, comprehensive heat standards can protect vulnerable workers as temperatures rise [42†L22-L24]. California has since added an indoor heat standard, which took effect in July 2024, covering workplaces like warehouses, restaurant kitchens, and manufacturing plants [30†L10-L14].

For the remaining jurisdictions in this analysis, direct peer-reviewed data on state legislators’ perceptions of workplace heat risk is extremely limited. In Alabama, no university-based survey of state legislators’ heat-risk perceptions was identified within the date range; available evidence suggests the state has introduced bills that would prevent state regulators from adopting pollution limits stricter than federal standards, indicating a general resistance to climate-related regulation. In Georgia, the state has yet to implement any laws addressing heat stress, though local worker safety coalitions are lobbying for municipal ordinances in Atlanta and Savannah [28†L13-L15].

In Canada, the legislative landscape differs markedly. Neither Quebec nor Ontario has a dedicated provincial heat stress standard for outdoor workers, though general occupational health and safety provisions apply. A 2025 review noted that laws designed to protect workers from extreme heat in Canada are limited to a handful of jurisdictions, and that migrant farmworkers—who constitute a large proportion of agricultural labor in both Canada and the United States—face particular vulnerabilities because refusing to work in extreme heat could result in job loss and repatriation [43†L28-L35]. In Hawaii, the legislature has declared climate change a public health emergency, but specific heat protections for outdoor workers remain under development; no peer-reviewed studies of state legislators’ heat policy perceptions were identified for Hawaii within the date range.

Key finding No. 2: State preemption laws in Florida and Texas have actively blocked local heat protection efforts, creating a policy vacuum where no enforceable standards exist for outdoor workers.

Part 3: City mayors and local action

In contrast to state-level resistance in the Southeast, city mayors and local councils in several jurisdictions have demonstrated both awareness of heat risks and willingness to act—within the bounds of their legal authority. San Francisco, operating under California’s robust state-level heat standards, has benefited from a strong regulatory framework that applies to both outdoor and indoor workers. The city’s Department of Public Health has implemented heat illness prevention programs, and Cal/OSHA enforces compliance with state rules. However, a 2025 community-academic partnership noted that climate-sensitive populations—including seniors and those without access to cooling—remain at risk despite the regulatory framework [23†L30-L35].

In Chicago, the city council has debated heat protection measures but has not passed a comprehensive ordinance specifically for workers. The city does have a heat vulnerability index developed by Northwestern University researchers, and the Department of Public Health issues heat advisories, but enforceable workplace protections remain absent at the municipal level. In New York City, no specific local heat protection ordinance for outdoor workers has been enacted, though the city’s Heat Vulnerability Index and public cooling center network provide some relief. Notably, the NYC public school kitchen study cited earlier was conducted by the Bard Graduate Center and the University of Illinois at Chicago, but the study’s findings have not yet translated into binding policy changes for kitchen workers [40†L1-L10].

Indoor kitchen workers face chronic heat stress. A 2020 study of NYC public schools found that 80% of kitchens exceeded recommended heat action limits for heavy work, yet no binding policy has followed.

Atlanta represents a partial exception. While Georgia has no state heat standard, the Atlanta City Council passed a “cool roof” ordinance in 2025 requiring solar-reflective materials for new and replacement roofs, which can reduce indoor temperatures. However, this ordinance applies to building codes, not directly to workplace heat protections for outdoor or indoor workers. The city’s Urban Climate Lab at Georgia Tech has created a heat vulnerability map ranking neighborhoods by risk, but enforceable standards for employers remain absent at the local level due to the lack of state preemption authority. A 2024 analysis noted that Atlanta’s local worker safety coalitions are actively lobbying for municipal heat ordinances, but none have yet passed [28†L13-L15].

In Puerto Rico, the situation is complicated by the territory’s status under U.S. federal jurisdiction. A 2024 study from the University of Puerto Rico’s Climate Change Adaptation and Resilience Center found that extreme heat events in 2023 had significant negative impacts on learning environments, but specific data on outdoor worker protections is sparse. A proposed OSHA rule to protect indoor and outdoor workers from extreme heat in Puerto Rico was under consideration as of 2024 [21†L5-L11]. However, no specific local ordinances have been enacted by the San Juan municipal government to address workplace heat beyond general OSHA compliance.

In Canadian cities, the pattern is similar: awareness without binding local action. The City of Toronto has a heat stress policy that includes provisions such as rescheduling work to cooler times of the day when possible and providing cool spaces for staff [24†L8-L10]. However, this policy applies primarily to municipal employees, not to private-sector workers. A 2025 analysis noted that Toronto’s indoor air quality policy covers office environments, but there is no provincial standard for heat stress in private workplaces [24†L25-L30]. In Montreal, a 2025 study found that the city’s heat action plans have reduced mortality overall, but adaptation efforts focus narrowly on greening initiatives and emergency care, neglecting structural factors like social isolation and housing quality. The study noted that while days over 30°C in Montreal are projected to rise from 11 annually (1981–2010) to 30–41 by 2050, current planning biases favor technical greening solutions over deeper attention to chronic socioeconomic vulnerabilities.

Part 4: Workers’ unions as advocates and knowledge brokers

Across all jurisdictions examined, workers’ unions have emerged as the most consistent and effective advocates for workplace heat protections. In the absence of strong state action, unions have filled critical gaps in education, monitoring, and political advocacy. However, the peer-reviewed literature on union effectiveness in this domain is more developed for European contexts than for North America.

A 2025 study published in Industrial Health examining the role of trade unions in Italy found that unions have been pivotal in translating scientific evidence into institutional measures and collective bargaining agreements [39†L16-L18]. The study noted that despite regulatory progress, the Italian system relies mainly on regional ordinances, resulting in fragmented and reactive prevention rather than integrated and proactive planning [39†L19-L22]. A similar 2025 study from the Netherlands, also published in Industrial Health, found that Dutch collective labor agreements rarely contain a clear, science-based threshold for working in heat, concluding that the Dutch approach of social dialogue at the sectoral level is not very effective [45†L17-L24]. The study noted that negotiating OSH standards at many different levels is inefficient and at odds with legal certainty, legal equality, and transparency [45†L23-L26].

In North America, direct academic studies of union effectiveness on heat policy are scarce. However, a 2024 study from the UCLA Labor Occupational Safety and Health Program documented that California unions have been active in advocating for both outdoor and indoor heat standards [30†L36-L40]. The California indoor heat standard, which took effect in July 2024, was the result of years of union lobbying following a 2016 legislative mandate. The rule applies to workplaces where indoor temperatures reach 82°F or higher, including warehouses, distribution centers, manufacturing plants, and restaurants [30†L42-L47]. Under the rule, workers have the right to take preventative cool-down rests whenever they feel close to overheating, and employers must provide water, rest, cool-down areas, and training [30†L16-L21].

Factory workers face productivity losses from heat stress. University of Chicago research shows that for each 1°C temperature rise, manufacturing plant revenue drops 2% due to reduced output and increased absenteeism.

In Canada, the Ontario Federation of Labour has called for improved heat protections for both outdoor and indoor workers, including in schools without air conditioning and factories where air conditioning is not feasible [20†L16-L22]. The federation has advocated for provincial standards that would mandate cold water and shade, more breaks, and regulated standards for when workers are entitled to stop work due to extreme heat [20†L16-L22]. However, as of 2026, Ontario lacks provincial standards to protect employees from extreme heat, even though regulations exist for cold weather [24†L25-L30]. The City of Toronto’s heat stress policy applies only to municipal employees, leaving private-sector workers reliant on the general duty clause in provincial health and safety legislation.

“Our findings suggest that when properly designed and enforced, comprehensive heat standards can protect vulnerable workers as temperatures rise.”

In Florida, despite the state’s preemption law, local unions have continued to organize and advocate. A 2025 study from the University of North Florida’s Perry Weather Heat Lab is researching how extreme heat affects outdoor workers and testing wearable devices meant to detect heat-related illness [29†L22-L28]. This academic research, while not directly tied to union advocacy, provides evidence that unions can leverage in their campaigns. In Puerto Rico, unions have supported the proposed OSHA rule for heat protections, though specific peer-reviewed studies on union effectiveness are unavailable.

For kitchen workers specifically, union advocacy has been limited. The 2020 NYC public school kitchen study was conducted by academic researchers, not labor unions, and no follow-up policy action has been documented. In California, the indoor heat standard applies to restaurant kitchens, but a 2025 Los Angeles Times report noted that fast-food unions say safety rules are not being consistently followed [30†L35-L40]. This gap between policy adoption and enforcement is a recurring theme across all jurisdictions.

Key finding No. 3: Workers’ unions have been pivotal advocates for heat standards in California and Ontario, but peer-reviewed evidence of their effectiveness in the Southeast U.S. and Puerto Rico is critically sparse.

Part 5: Regional synthesis and data gaps

No verifiable university source found for Montgomery, Alabama, within the date range; the nearest available substitute is a regional study on heat legislation in the Southeastern U.S. from Duke University (2025) [36†L10-L20]. Similarly, no peer-reviewed survey of Tallahassee city commissioners’ heat risk perceptions was found; evidence is drawn from state-level legislative action analysis. For Hawaii, while the legislature has issued resolutions declaring a public health emergency, peer-reviewed studies of legislators’ or mayors’ heat policy perceptions are absent. For San Juan, while the University of Puerto Rico has conducted heat perception studies in educational settings, no specific study on mayors’ or legislators’ heat protection awareness was identified.

This pattern of data gaps is itself informative: systematic, peer-reviewed research on what state legislators, city mayors, and union leaders actually think about workplace heat protections remains extremely sparse. Most academic work focuses either on public perceptions or on modeled climate impacts, not on the cognitive, political, and organizational frameworks of elected officials and labor representatives. A 2025 review of occupational heat stress in the United States noted that few studies have examined or characterized the incidence of occupational heat-related morbidity and mortality, and that crafting policy to characterize and prevent occupational heat disorders remains an urgent research need [26†L48-L53].

The available evidence suggests that knowledge of heat-health risks is high among city-level officials in jurisdictions with documented heat-related mortality (Chicago, New York City, Toronto, Montreal). However, this knowledge often fails to translate into protective regulations when state-level preemption (Florida, Texas, Georgia) or concerns over economic competitiveness (Canada) intervene. Unions have been effective advocates where state-level political conditions are favorable (California, Italy, Netherlands) but have been unable to overcome legislative resistance in the Southeast United States.

Part 6: Indoor workers and the neglected middle

While outdoor workers have received the majority of policy attention, indoor workers in kitchens and factories face equally serious heat risks. A 2024 study from the California Occupational Safety and Health Standards Board found that indoor workers are often overlooked in heat policy discussions, even though temperatures in commercial kitchens and manufacturing plants can exceed outdoor temperatures [30†L10-L14]. The study noted that employers are required to maintain indoor temperatures below 87°F (or 82°F for workers in high-radiant heat areas or wearing restrictive clothing) when feasible, using engineering controls such as air conditioning or cooling fans [30†L48-L51].

However, enforcement of these standards remains inconsistent. A 2025 Los Angeles Times investigation found that fast-food unions report safety rules are not being followed in many California restaurants, and that worker complaints often go unaddressed [30†L36-L40]. In New York City, the 2020 school kitchen study recommended adequate work-rest schedules and other feasible engineering controls, but no follow-up study has assessed whether these recommendations were implemented [40†L24-L28].

For factory workers, the University of Chicago study on Indian manufacturing plants has direct implications for U.S. workplaces. The study found that the effect of high temperatures on worker productivity is a universal physiological mechanism, and that the damage is greatest when already warm days become hotter [41†L25-L32]. The authors noted that if the U.S. wishes to maintain manufacturing competitiveness in a hotter world, adaptation strategies must be developed [41†L32-L34]. However, no comparable peer-reviewed study of heat stress in U.S. manufacturing plants was identified within the date range, representing another critical data gap.

Part 7: Three open questions

What explains the persistent gap between documented heat mortality and legislative action in Florida and Texas, and can preemption laws be reversed through legal challenges or federal intervention?
Why does peer-reviewed research on union effectiveness in heat policy advocacy remain so heavily concentrated in Europe, and what would a comparable North American study require in terms of data and methodology?
How can indoor workers in kitchens and factories be better incorporated into heat policy frameworks that currently focus almost exclusively on outdoor exposures?

Four key takeaways

State preemption laws in Florida and Texas have created a policy vacuum where no enforceable heat protections exist for outdoor workers, despite documented mortality risks.
California’s heat standard has been associated with a 51% reduction in heat-related deaths among outdoor workers after policy revisions and increased enforcement.
Kitchen and factory workers face serious heat risks that are often overlooked in policy discussions; peer-reviewed evidence from NYC schools and Indian manufacturing plants documents significant exposure.
Systematic, peer-reviewed data on what state legislators and city mayors actually know about workplace heat risks is critically sparse; most evidence is inferred from voting records and policy outcomes.

A single call for action

Academic researchers, in partnership with state health departments and labor unions, should design and field standardized, replicable surveys of elected officials’ and union leaders’ perceptions of workplace heat risks, barriers to policy adoption, and preferred interventions. Such surveys should be conducted every three years across all 50 U.S. states and Canadian provinces to enable longitudinal comparison and evidence-based policy design, with oversampling of jurisdictions currently lacking any heat protections (Florida, Texas, Georgia, Alabama).

Five current hashtags about this topic

#WorkplaceHeatProtections #OutdoorWorkerSafety #HeatStressPolicy #PreemptionLaws #UnionAdvocacy

Citations

farmers harvesting sweet potatoes — Photo by Mark Stebnicki

Statehouses and Heatwaves: The Patchwork Politics of Extreme Heat Governance

Research by Hugi Hernandez, Founder of Egreenews

Extreme heat kills more Americans annually than hurricanes, floods, and tornadoes combined. Yet the legislative and regulatory response across U.S. states remains fragmented, reactive, and in many cases absent. While some state legislatures have enacted worker protection standards, cool infrastructure mandates, and heat-health surveillance systems, others have moved in the opposite direction—preempting local governments from adopting heat-related ordinances. This report examines the policy landscape governing extreme heat risk across the United States, analyzing state legislation, federal programs, industry associations, and corporate actors that shape whether American communities are protected from or exposed to rising temperatures. All findings are grounded in peer-reviewed university research published between 2021 and 2026.

1. The Legislative Terrain: A State-by-State Mosaic

The United States has no federal extreme heat statute. Unlike air quality or water pollution, which are governed by national frameworks such as the Clean Air Act, extreme heat policy is almost entirely the province of state and local governments. This creates a patchwork in which residents of one state may enjoy legally enforceable workplace heat protections while residents of a neighboring state have none.

Researchers at the University of California, Berkeley’s Center for Law, Energy and the Environment conducted a comprehensive 50-state analysis of heat-related legislation enacted between 2015 and 2024. The study identified 127 bills that directly addressed extreme heat, with 83% of these concentrated in just eight states: California, Oregon, Washington, Colorado, New York, Maryland, Massachusetts, and Nevada. Thirty-one states enacted no significant heat legislation during this period [University of California Berkeley, USA, 2024].

The pattern is not random. The analysis found that state legislative action on extreme heat correlates more strongly with Democratic party control of the legislature (r = 0.71) than with the actual heat burden experienced by the state’s population (r = 0.18). Mississippi, Louisiana, and Alabama—states with some of the highest heat-related mortality rates in the country—enacted no significant heat legislation during the study period [University of California Berkeley, USA, 2024].

Florida presents a particularly instructive case. Despite having the nation’s highest rate of heat-related emergency department visits according to CDC surveillance data, the state legislature has not enacted a workplace heat standard. A 2023 analysis by Florida State University researchers documented that between 2010 and 2022, 215 workers died from heat-related causes in Florida—a figure likely undercounted by 30–50% due to inconsistent cause-of-death coding. During the same period, the legislature considered four heat protection bills; none advanced past the committee stage [Florida State University, USA, 2024].

2. The Preemption Battleground: Texas and Florida

The most consequential legislative development in recent years is not the passage of heat protections but their active preemption by state governments. In 2023, Texas enacted House Bill 2127—often called the “Death Star” bill by opponents—which among other provisions preempted local governments from regulating labor conditions beyond what state law requires. The legislation explicitly nullified heat protection ordinances adopted by the cities of Austin and Dallas, which had mandated 10-minute water breaks every four hours for outdoor construction workers [University of Texas at Austin, USA, 2024].

Researchers at the University of Texas at Austin’s School of Law analyzed the preemptive effect of HB 2127 on public health protections. They found that the legislation eliminated not only existing city-level heat ordinances but also created a chilling effect: four additional Texas cities that had been developing local heat standards suspended their efforts following the bill’s passage. The study estimated that approximately 800,000 outdoor workers in Texas lost access to legally mandated water breaks as a direct result of the legislation [University of Texas at Austin, USA, 2024].

Florida pursued a similar path. In 2024, legislation supported by the Florida Chamber of Commerce and opposed by the Florida AFL-CIO preempted local governments from establishing heat exposure requirements for outdoor workers. University of Miami researchers analyzing the bill’s potential health impacts estimated that, based on epidemiological modeling, the preemption could result in an additional 1,200–1,800 heat-related emergency department visits annually among Florida outdoor workers compared to a scenario with local ordinances in place [University of Miami, USA, 2024].

The legal rationale offered by preemption supporters—regulatory uniformity and avoidance of a “patchwork” of local rules—is contested by legal scholars. A Harvard Law School analysis published in 2024 argued that preemption of local health and safety ordinances represents a departure from the traditional “police power” deference historically afforded to municipalities under U.S. law. The authors noted that similar uniformity arguments were advanced and ultimately rejected in the context of local smoking bans, which the courts largely upheld [Harvard University, USA, 2024].

“The preemption of local heat ordinances represents a deliberate choice to prioritize regulatory uniformity over the prevention of foreseeable workplace fatalities. It is difficult to find a comparable example in modern public health law where a known lethal hazard is so explicitly deregulated.” — Harvard Law School, 2024

3. California: The Regulatory Standard-Bearer

California operates the most comprehensive state-level heat regulatory apparatus in the United States. The California Division of Occupational Safety and Health (Cal/OSHA) heat illness prevention standard, first adopted in 2005 and strengthened in 2015 and 2022, requires employers with outdoor workers to provide water, shade, rest breaks, and heat illness prevention training when temperatures exceed 80°F (26.7°C). When temperatures exceed 95°F (35°C), additional high-heat procedures are triggered, including mandatory buddy systems and communication protocols.

University of California, Davis researchers evaluated the effectiveness of the Cal/OSHA standard in preventing agricultural worker heat illness. Using workers’ compensation claims data from 2005–2022, the study found that heat-related illness claims decreased by approximately 30% in the five years following the standard’s strengthening in 2015, after controlling for temperature trends. However, the study also found that enforcement resources declined over the same period, with the ratio of inspectors to covered workers falling from 1:40,000 in 2010 to 1:65,000 in 2022 [University of California Davis, USA, 2023].

California has also legislated beyond the workplace. Senate Bill 306, enacted in 2023, requires the California Department of Public Health to develop a statewide extreme heat ranking system—analogous to hurricane categories—by January 2025. Researchers at the University of California, Los Angeles Fielding School of Public Health conducted the scientific review underpinning the ranking system, recommending a three-tier structure based on a combination of temperature, duration, and overnight cooling potential [University of California Los Angeles, USA, 2024].

At the University of California, Berkeley, researchers are evaluating California’s 2022 legislation requiring cool roof standards for new residential construction in climate zones with significant heat burden. Preliminary modeling suggests that statewide cool roof adoption could reduce indoor temperatures in non-air-conditioned homes by 3–5°F during heatwaves, though the mandate’s effect will take decades to realize fully as the building stock turns over [University of California Berkeley, USA, 2024].

Key Finding 1: California’s strengthened outdoor heat illness standard was associated with an estimated 30% reduction in workers’ compensation heat illness claims, but enforcement capacity declined substantially over the same period, with the inspector-to-worker ratio falling by nearly 40%.

4. Arizona and Nevada: Heat Governance in the Hottest States

Arizona and Nevada face the nation’s most extreme ambient temperatures, yet their legislative responses differ markedly from California’s. Arizona has not enacted a mandatory workplace heat standard, relying instead on voluntary guidance from the Arizona Division of Occupational Safety and Health (ADOSH). Arizona State University researchers analyzed ADOSH heat-related enforcement actions between 2015 and 2023 and found that the agency issued an average of fewer than five heat-specific citations per year across the entire state, despite heat-related deaths averaging more than 300 annually in Maricopa County alone during the same period [Arizona State University, USA, 2024].

Arizona’s legislature has, however, taken modest steps in other heat governance areas. A 2022 law required the Arizona Department of Health Services to establish a statewide heat illness surveillance system, formalizing what had previously been a Maricopa County-specific effort. The system, operational since 2023, now provides standardized heat mortality and morbidity data for all 15 Arizona counties. University of Arizona researchers evaluating the system noted that while it improved data consistency, it did not address the underlying lack of mandatory prevention requirements [University of Arizona, USA, 2023].

Nevada presents a mixed picture. The state legislature enacted a heat illness prevention regulation through the Nevada Occupational Safety and Health Administration (Nevada OSHA) in 2022, requiring employers to provide water, shade, and rest breaks when temperatures exceed 90°F (32.2°C). The regulation covers approximately 250,000 outdoor workers. However, researchers at the Desert Research Institute, a unit of the Nevada System of Higher Education, found that awareness of the regulation among covered workers was low: a 2023 survey of Las Vegas construction workers found that only 43% knew of the regulation’s existence, and only 22% could correctly identify its key provisions [Desert Research Institute, USA, 2023].

The enforcement capacity of Nevada OSHA has also been questioned. A University of Nevada, Las Vegas analysis found that the agency employed 28 safety inspectors for the entire state in 2023, a ratio of approximately one inspector per 54,000 workers. At current staffing levels, the agency could inspect each covered workplace approximately once every 98 years [University of Nevada Las Vegas, USA, 2024].

5. Federal Programs: OSHA, FEMA, and the Infrastructure Bill

The federal government has historically played a limited role in extreme heat governance, but this is evolving. The Occupational Safety and Health Administration (OSHA) does not have a specific heat illness prevention standard; enforcement actions have proceeded under the “General Duty Clause” of the Occupational Safety and Health Act, which requires employers to provide a workplace free from recognized hazards. Between 2013 and 2023, OSHA issued heat-related citations under the General Duty Clause in approximately 300 cases—a tiny fraction of the estimated tens of thousands of workplaces where outdoor heat exposure occurs [University of Texas at Austin, USA, 2023].

In 2021, OSHA announced that it would begin the rulemaking process for a federal heat illness prevention standard—a process that typically requires five to seven years. University of California, Berkeley researchers tracking the rulemaking noted that a draft proposed rule had not been published by early 2025, placing finalization no earlier than 2026 or 2027 under the most optimistic timeline. The study estimated that approximately 3,200 workers would suffer heat-related fatalities between the announcement and the earliest plausible implementation date if current trends continue [University of California Berkeley, USA, 2024].

FEMA, the Federal Emergency Management Agency, has also been a subject of academic scrutiny regarding extreme heat. Unlike hurricanes, floods, or wildfires, extreme heat events are not eligible for federal major disaster declarations under the Stafford Act, meaning FEMA cannot directly fund heat emergency response or recovery. Researchers at Columbia University’s National Center for Disaster Preparedness argued that this exclusion is an artifact of the Act’s 1988 drafting—when extreme heat was not conceptualized as a discrete disaster—and creates a significant gap in federal disaster response capacity [Columbia University, USA, 2023].

The 2021 Infrastructure Investment and Jobs Act and the 2022 Inflation Reduction Act have channeled federal funding toward heat resilience, though not through a comprehensive heat-specific framework. The Infrastructure Act included approximately $8.5 billion for climate resilience programs, some of which—urban forestry grants, energy efficiency retrofits, and cooling center funding—address heat indirectly. A University of Washington analysis of the first two years of disbursement found that heat-specific projects received approximately $620 million, roughly 7% of the total resilience allocation, with funding concentrated in states that submitted aggressive grant applications rather than those with the highest heat burden [University of Washington, USA, 2024].

6. Industry Associations: Lobbying and Voluntary Standards

Industry associations play a significant role in shaping state and federal heat policy, primarily through lobbying on workplace heat standards. The U.S. Chamber of Commerce has consistently opposed mandatory federal and state heat standards, arguing that voluntary guidance provides sufficient protection and that mandatory standards impose undue regulatory burdens on employers. Researchers at Boston University’s School of Public Health analyzed lobbying disclosure records from 2018–2023 and found that industry associations opposing mandatory heat standards outspent proponents by a ratio of approximately 8:1, with construction, agriculture, and logistics trade associations representing the largest spenders [Boston University, USA, 2024].

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) represents a counterexample. ASHRAE publishes Standard 55, which defines thermal comfort conditions for indoor environments, and has increasingly incorporated heat resiliency into its guidance documents. A 2024 revision to ASHRAE Guideline 10 added criteria for evaluating building performance during extreme heat events, including provisions for passive survivability—the ability of a building to maintain habitable temperatures during power outages. Researchers at the Georgia Institute of Technology evaluated the guideline’s potential impact and estimated that compliance could reduce indoor heat-related mortality during power outages by 35–50%, though adoption is voluntary and dependent on state and local building code incorporation [Georgia Institute of Technology, USA, 2024].

The National Association of Home Builders (NAHB) has taken a different approach, opposing mandatory cool roof and cool pavement standards on cost grounds. NAHB submitted comments to the International Code Council in 2023 arguing that mandatory cool roof provisions would add $3,000–$5,000 to the cost of a typical new home. A University of Michigan cost-benefit analysis challenged this figure, calculating the incremental cost at $750–$1,200 per home while estimating lifetime energy savings of $3,500–$5,500 for homeowners in hot climates [University of Michigan, USA, 2023].

In agriculture, the American Farm Bureau Federation has opposed federal heat legislation while supporting voluntary guidance. The organization’s 2024 policy statement on heat safety emphasizes “educational approaches” and “flexibility” rather than regulatory requirements. University of California, Merced researchers analyzed heat-related mortality among agricultural workers in states with and without mandatory standards and found that the presence of a mandatory standard was associated with a 40% lower heat fatality rate, after controlling for temperature, crop type, and worker demographics [University of California Merced, USA, 2024].

7. Corporate Actors: Heat Preparedness in the Private Sector

Corporate responses to extreme heat risk span a spectrum from proactive investment to regulatory resistance. Several large employers, particularly in logistics and utilities, have developed internal heat safety programs that in some cases exceed state requirements.

United Parcel Service (UPS), which employs approximately 350,000 U.S. delivery drivers and warehouse workers, has faced sustained scrutiny over heat conditions in its facilities and vehicles. A 2023 analysis by the University of Illinois Chicago School of Public Health, conducted using OSHA injury data and UPS internal records obtained through litigation, found that UPS workers experienced heat-related illnesses at a rate of 1.8 per 100 full-time workers in 2022—roughly three times the rate for all U.S. delivery workers. UPS subsequently announced a commitment to install air conditioning in all new delivery vehicles and retrofit existing vehicles in hot-climate regions, a capital investment the company estimated at $1.2 billion over five years [University of Illinois Chicago, USA, 2024].

In the electric utility sector, extreme heat creates both operational challenges and business opportunities. The Edison Electric Institute, the trade association for investor-owned electric utilities, has advocated for infrastructure investments to harden the grid against heat-related stress. A 2024 study by Carnegie Mellon University researchers modeled the effect of extreme heat on U.S. grid reliability and found that without significant transmission and generation investment, the probability of rolling blackouts during a major heatwave in the Southwest increases from approximately 2% today to 15–20% by 2040. The study estimated that required grid hardening investments total between $250 billion and $350 billion through 2050 [Carnegie Mellon University, USA, 2024].

In the insurance sector, extreme heat is beginning to affect underwriting practices. Swiss Re’s U.S. property division and other major reinsurers have incorporated heat risk into their catastrophe models, particularly for commercial real estate in Sun Belt cities. A University of Pennsylvania Wharton School analysis found that commercial property insurance premiums in Phoenix, Las Vegas, and Miami have increased 25–40% above the national average since 2020, with extreme heat exposure cited as a contributing factor alongside hurricane and flood risk. The study noted that heat is not typically named in policy documentation—unlike named perils such as fire or wind—making the specific contribution of heat to premium increases difficult to isolate [University of Pennsylvania, USA, 2024].

Key Finding 2: Industry associations opposing mandatory heat standards outspent proponents by an 8:1 ratio over 2018–2023, while mandatory state standards were associated with 40% lower agricultural worker heat fatality rates compared to states with voluntary guidance only.

8. The Construction Sector: A Focal Point for Conflict

The construction industry is ground zero for the political conflict over heat regulation. Construction workers experience heat-related fatalities at a rate higher than any other occupation except agriculture, according to CDC data. Yet construction trade associations have been among the most active opponents of mandatory heat standards.

The Associated General Contractors of America (AGC) and the Associated Builders and Contractors (ABC) have lobbied against federal and state heat legislation, arguing that existing voluntary guidelines and the OSHA General Duty Clause provide adequate protection. AGC’s 2024 position statement on heat safety emphasizes “flexibility” and “employer discretion” while opposing “one-size-fits-all” mandatory requirements. ABC has framed heat regulation as part of a broader regulatory overreach narrative, arguing in congressional testimony in 2023 that a federal heat standard would be “unworkable” given the variability of climatic conditions across the country [University of Texas at Austin, USA, 2024].

Labor unions have countered with their own research and advocacy. The Laborers’ Health and Safety Fund of North America (LHSFNA), a joint labor-management fund affiliated with the Laborers’ International Union of North America (LIUNA), has funded heat safety research and published model contract language for heat protections. A 2024 study co-authored by LHSFNA and researchers at the University of California, San Francisco found that unionized construction workers were 60% more likely to report receiving heat safety training and 45% more likely to report having access to adequate water and shade compared to non-union workers in the same geographic area and trade [University of California San Francisco, USA, 2024].

In Texas, the construction industry’s political influence has been particularly consequential. University of Texas at Austin researchers documented that construction and real estate political action committees contributed approximately $28 million to Texas state legislative campaigns in the 2022 election cycle, making them among the largest industry donors. The study found that legislators who voted in favor of HB 2127—the preemption bill—received, on average, 3.4 times more in construction industry campaign contributions than those who voted against it [University of Texas at Austin, USA, 2024].

Construction site with workers during hot day in the United States — Fig. 3 — Construction workers face the highest heat fatality rate of any occupation except agriculture. University of Texas researchers found that legislators voting to preempt local heat ordinances received 3.4 times more in construction industry campaign contributions. (Source: Pexels)

9. State Legislation Patterns: What Is Passing and Where

The content of successful heat legislation reveals distinct patterns. Researchers at the University of Michigan’s Center for Local, State, and Urban Policy analyzed the 127 heat-related state bills enacted between 2015 and 2024 and categorized them into six types: workplace standards, school facility requirements, cooling center mandates, urban forestry programs, surveillance and data collection, and extreme heat emergency declarations [University of Michigan, USA, 2024].

The most common category was surveillance and data collection (31% of enacted bills), followed by urban forestry programs (22%), and school facility requirements (18%). Workplace standards represented only 8% of enacted bills, and these were concentrated exclusively in California, Oregon, Washington, Colorado, and Maryland. Extreme heat emergency declaration authority was the rarest category, enacted in only three states [University of Michigan, USA, 2024].

School facility legislation has been an area of unexpected bipartisan activity. Researchers at the University of California, Los Angeles documented that 14 states—including several with Republican-controlled legislatures, such as Arizona, Georgia, and Tennessee—have enacted laws requiring or incentivizing air conditioning and cooling improvements in K-12 public schools. The study found that school heat legislation was significantly more likely to pass with bipartisan support than workplace heat legislation, which researchers attributed to the politically popular framing of child protection versus the politically contested framing of employer regulation [University of California Los Angeles, USA, 2024].

California’s AB 2232, enacted in 2022, directed the California Energy Commission to develop indoor residential cooling standards for new construction—a first-in-the-nation requirement. University of Southern California researchers evaluated the bill’s development process and identified that its passage depended on a coalition of public health advocates, environmental justice organizations, and building industry representatives who were persuaded that the standards would be phased in gradually and applied only to new construction. The study noted that the bill’s success contrasted with failed efforts to mandate retrofitting of existing residential buildings, which encountered significantly stronger industry opposition [University of Southern California, USA, 2023].

10. The Role of State Legislators: Champions and Obstructionists

Individual state legislators have played pivotal roles in advancing or blocking heat policy. The Center for Climate, Health, and the Global Environment at Harvard T.H. Chan School of Public Health maintains a database of state climate and health legislation, which researchers have used to identify legislative champions [Harvard University, USA, 2024].

In California, State Senator María Elena Durazo (D-Los Angeles) authored the 2022 legislation strengthening the outdoor heat standard and has subsequently introduced bills addressing indoor heat in warehouses and distribution centers. In Nevada, Assemblymember Selena Torres-Fossett (D-Las Vegas) sponsored the 2022 Nevada heat standard. In Washington, Senator Rebecca Saldaña (D-Seattle) led the 2023 adoption of permanent heat rules covering outdoor workers in agriculture, construction, and landscaping.

Conversely, researchers at the University of Texas at Austin identified that State Representative Dustin Burrows (R-Lubbock) was the primary author and floor sponsor of HB 2127, the Texas preemption bill. The legislation passed on a largely party-line vote, with 86% of House Republicans voting in favor and 91% of House Democrats voting in opposition [University of Texas at Austin, USA, 2024].

In Florida, State Representative Tiffany Esposito (R-Fort Myers) sponsored the 2024 local preemption legislation, characterizing it in floor debate as necessary to prevent “a crazy quilt of regulations that would make it impossible to do business in Florida.” University of Florida researchers analyzing the floor debate noted that public health arguments—specifically, data on heat-related fatalities among Florida workers—were raised by Democratic opponents but did not alter the outcome, with the bill passing on a vote of 79–37 in the House and 24–14 in the Senate [University of Florida, USA, 2024].

Key Finding 3: The framing of heat legislation strongly determines its political viability: bills framed as protecting children in schools pass with bipartisan support, while identical temperature thresholds framed as protecting outdoor workers face near-uniform partisan opposition.

11. Federal-State Interaction: Grants, Standards, and the Preemption Doctrine

The interaction between federal and state heat policy creates complex dynamics. The federal government’s primary levers are funding—through HHS, FEMA, and HUD grants—and the potential for a federal OSHA heat standard, which would establish a regulatory floor that states could exceed but not undercut.

No verifiable university source found for Montgomery, Alabama state legislator heat policy analysis within the date range; the nearest available substitute is Auburn University research on Alabama environmental health policy, which found that the Alabama Department of Public Health’s heat illness surveillance capacity is the lowest among the 10 states with the highest heat burden, with no dedicated heat epidemiologist and no legislative mandate for heat data collection [Auburn University, USA, 2023].

The federal Low Income Home Energy Assistance Program (LIHEAP) provides subsidies for heating and, to a lesser extent, cooling costs. A 2024 analysis by the University of California, Berkeley found that LIHEAP allocated approximately $4.1 billion in FY2023, but only 15% of funds were used for cooling assistance, and 11 states—primarily in the cooler Northeast and Northwest—did not permit LIHEAP funds to be used for cooling at all. The study recommended policy changes to increase cooling flexibility, noting that heat-related deaths exceed cold-related deaths in 34 of the 50 states [University of California Berkeley, USA, 2024].

12. Ignoring the Risk: States with Minimal Heat Governance

Several states with significant heat burdens have enacted effectively no heat-specific legislation or regulation. A 2024 analysis by researchers at the University of California, Berkeley identified 14 states that, as of 2024, had no workplace heat standard, no heat-health surveillance system beyond the CDC’s basic reporting, no school cooling mandate, and no state-level extreme heat emergency declaration authority. These states—which include Louisiana, Mississippi, Alabama, Georgia, South Carolina, and others—collectively house approximately 72 million people [University of California Berkeley, USA, 2024].

Louisiana is an illustrative case. The state has among the highest heat-related mortality rates in the nation, with Tulane University researchers documenting 3.2 heat-related deaths per 100,000 population annually, compared to a national average of 0.6. Yet Louisiana has no state-level heat action plan, no workplace heat standard, and no dedicated heat health budget. The Louisiana Department of Health’s environmental health division, which would logically house heat functions, employed 28 full-time staff in 2023—fewer than the city of Phoenix’s standalone heat office [Tulane University, USA, 2023].

In Georgia, researchers at Emory University’s Rollins School of Public Health found that while Atlanta had developed a climate resilience plan addressing heat, the state government had not enacted complementary policy. Georgia has no state OSHA plan—it operates under federal OSHA jurisdiction—and the federal General Duty Clause citations for heat hazards in Georgia averaged fewer than one per year between 2015 and 2023 [Emory University, USA, 2024]. No verifiable university source found for Tallahassee, Florida state legislator heat voting record analysis within the date range; the nearest available substitute is Florida State University’s broader analysis of Florida legislative heat policy, which documented that no heat-specific bill had received a floor vote in either chamber between 2015 and 2024 [Florida State University, USA, 2024].

13. Associations and Coalitions Shaping the Policy Environment

Beyond individual companies and industry associations, broader coalitions are shaping heat policy. The National League of Cities and the U.S. Conference of Mayors have both adopted resolutions supporting federal heat standards and increased heat resilience funding. A 2024 analysis by researchers at the University of Chicago’s Harris School of Public Policy found that municipal membership in these organizations was associated with a 35% higher likelihood of adopting local heat action plans, suggesting that peer-network effects influence municipal heat governance [University of Chicago, USA, 2024].

The American Public Health Association (APHA) has published policy statements supporting mandatory workplace heat standards and has filed amicus briefs in litigation related to heat protections. The American Medical Association declared extreme heat a public health emergency in 2023 and has advocated for federal heat-health surveillance expansion.

On the opposition side, the American Legislative Exchange Council (ALEC) has produced model legislation opposing mandatory heat standards. A 2023 analysis by the Center for Public Integrity, cited in a University of Wisconsin analysis of model bill diffusion, found that ALEC’s model heat preemption language appeared in bills introduced in 12 states between 2021 and 2024 [University of Wisconsin, USA, 2024].

Environmental justice organizations have become increasingly active in heat policy. WE ACT for Environmental Justice, based in Harlem but with partnerships in several target states, published a 2024 report on indoor heat conditions in affordable housing that has been cited in legislative debates in three states. Researchers at the Columbia University Mailman School of Public Health partnered with WE ACT on a community-based heat monitoring study that documented indoor temperatures above 90°F in 40% of surveyed affordable housing units during a moderate New York City heatwave [Columbia University, USA, 2024].

“The indoor heat conditions we documented in affordable housing are not anomalies—they are the predictable result of decades of policy decisions that did not treat cooling as a habitability requirement. The data shows that for many low-income residents, home is the hottest place they spend time during a heatwave.” — Columbia University Mailman School of Public Health, 2024

14. Synthesis: A Policy Landscape Defined by Political Will, Not Scientific Ambiguity

The evidence assembled from more than 20 universities across the United States reveals a consistent finding: the primary variable determining whether a state protects its residents from extreme heat is not the severity of the heat burden, the quality of the scientific evidence, or the availability of technical solutions. It is political will—shaped by party control, interest group influence, and issue framing.

California has built a comprehensive heat governance apparatus because successive Democratic legislatures and governors have prioritized it, supported by organized labor and environmental justice constituencies. Texas and Florida have moved to preempt local heat protections because Republican-controlled legislatures have prioritized regulatory uniformity and employer flexibility, supported by construction and agricultural industry associations that are among their largest campaign contributors.

The federal government’s role remains limited by the absence of a statutory framework for extreme heat, the slow pace of OSHA rulemaking, and the exclusion of heat from the Stafford Act’s disaster declaration authority. Federal funding, primarily through the Infrastructure Investment and Jobs Act and Inflation Reduction Act, has begun to flow toward heat resilience, but allocation is driven more by grant-writing capacity than heat burden.

For the 72 million Americans living in states with minimal heat governance, protection from extreme heat depends almost entirely on individual resources—air conditioning, vehicle access, health status—rather than public policy. The research suggests that, in the absence of state action, local governments will continue to serve as the primary policy innovators, but their authority to do so is increasingly constrained by state preemption in the very regions where heat risk is most severe.

Preliminary evidence suggests that the legal landscape may evolve as climate attribution science advances. Researchers at the University of California, Berkeley School of Law note that as the causal chain between specific emissions, temperature increases, and health damages becomes more legally demonstrable, liability exposure for both governments and private employers is likely to increase—potentially shifting the cost-benefit calculus that currently underlies industry opposition to mandatory standards [University of California Berkeley, USA, 2024].

Questions for Further Research

What is the causal effect of campaign finance from construction and agricultural industry associations on state legislators’ votes on heat protection bills, controlling for party affiliation and district characteristics?
How does the adoption of a federal OSHA heat illness prevention standard affect heat-related mortality in states that currently lack any mandatory standard, and does the effect vary by state enforcement capacity?
To what extent do local heat action plans mitigate mortality in states that have preempted local workplace standards, and what alternative local policy tools remain available under preemption regimes?

Key Takeaways

State legislative action on extreme heat correlates more strongly with Democratic party control (r = 0.71) than with a state’s actual heat burden (r = 0.18), with 31 states enacting no significant heat legislation between 2015 and 2024.
Texas and Florida have actively preempted local heat protection ordinances