Working in the Heat: Leading Workforces Through Rising Temperatures and Unsettled Heat Rules
Download the article here:
Listen to a review of this article:
Abstract: This article examines occupational heat stress as a leadership and workforce issue following the hottest U.S. summer on record in 2026. It reviews global and U.S. evidence on exposure, documenting that more than 2.41 billion workers face excessive heat worldwide and that U.S. heat deaths averaged about 42 per year from 2011 to 2024, likely an undercount. Drawing on workers' compensation research, it shows that heat raises injury risk well beyond heat illness, reduces productivity, and falls disproportionately on new, low-wage, migrant, and subcontracted workers. The article situates these findings within a stalled federal OSHA rulemaking, expanding state and local standards, and international practice. It then outlines five evidence-based responses: heat illness prevention plans with heat-index triggers; acclimatization with water, rest, and shade; scheduling redesign; engineering controls; and heat-aware supervision, worker voice, and privacy-conscious monitoring. Documented examples span logistics, agriculture, construction, landscaping, manufacturing, food service, and public employment. The article concludes with three long-term capabilities for climate-adaptive workforce management.
The summer of 2026 was the hottest on record for the contiguous United States. According to reporting on the National Oceanic and Atmospheric Administration's seasonal summary, June through August ran about 3°F above the twentieth-century average, edging past the previous record summers of 1936 and 2021, and roughly 86% of Americans experienced at least 30 days of risky heat (Simon, 2026). Heat waves closed summer camps and outdoor events, and heat once again proved to be the deadliest weather hazard in the country (Stephens, 2026). For most leaders, those headlines arrive as a weather story. For the people who frame houses, pick crops, sort packages, deliver mail, cook in commercial kitchens, or tend furnaces, they arrive as a working condition.
Occupational heat stress has long been treated as a niche concern for safety professionals in a handful of hot industries. That framing no longer fits. Heat now shapes injury rates far beyond classic heat stroke, erodes productivity on factory floors and in warehouses, strains already fragile low-wage labor markets, and sits at the center of an unsettled regulatory fight in the United States. The federal Occupational Safety and Health Administration (OSHA) proposed its first heat standard in August 2024, but by late 2026 the rule was headed toward a supplemental proposal that observers expect to be weaker, a House committee had advanced a bill to block it, and federal heat inspections had declined (Stephens, 2026; Wittenberg, 2026). Meanwhile, states, cities, unions, and some employers have moved ahead on their own.
This creates a leadership problem rather than only a compliance problem. When regulatory signals are mixed, organizations that wait for a single federal rule will find themselves governed by a patchwork of state standards, local ordinances, collective agreements, customer codes of conduct, and litigation risk, while their workers absorb the physical cost of delay. The organizations that handle heat well treat it the way mature companies treat other predictable hazards: they plan for it, measure it, build it into how work is scheduled and supervised, and give workers real authority to stop when their bodies tell them to.
This article examines occupational heat stress as a workforce and leadership issue. It reviews what heat stress is and who bears it, summarizes the organizational and human consequences, and sets out five evidence-based responses illustrated by documented organizational examples across logistics, agriculture, construction, landscaping, manufacturing, food service, and public employment. It closes with three long-term capabilities that leaders can build so their organizations remain productive and humane in a hotter baseline climate.
The Occupational Heat Stress Landscape
Defining Heat Stress, Heat Strain, and Heat-Related Illness
Heat stress refers to the total heat load a worker experiences from the environment (air temperature, humidity, radiant heat from sun or equipment, and air movement), from the metabolic heat generated by physical work, and from clothing or protective equipment that limits cooling. Heat strain is the body's physiological response to that load: rising core temperature, increased heart rate, and sweating. When strain outpaces the body's ability to shed heat, workers experience heat-related illness, a spectrum that includes heat rash, heat cramps, heat syncope (fainting), heat exhaustion, rhabdomyolysis (a breakdown of muscle tissue that can damage the kidneys), and heat stroke, which can cause permanent disability or death (Congressional Research Service, 2026; National Institute for Occupational Safety and Health [NIOSH], 2016).
Two measurement terms recur throughout regulations and guidance. The heat index combines air temperature and relative humidity into a "feels like" value and is widely available from weather forecasts, which is why most U.S. state rules and OSHA's 2024 proposal use it to set triggers. The wet bulb globe temperature (WBGT) adds radiant heat and wind and is the metric preferred by occupational hygienists and used in NIOSH's recommended exposure limits (Tustin et al., 2018). NIOSH distinguishes a lower recommended alert limit for workers who are not yet acclimatized from a recommended exposure limit for acclimatized workers (NIOSH, 2016).
Acclimatization is the physiological adaptation that occurs when people gradually increase their time working in heat over one to two weeks. It improves sweating efficiency and cardiovascular stability, but it is lost relatively quickly after time away. NIOSH and OSHA recommend that new workers spend no more than 20% of a normal shift in the heat on the first day and increase by no more than 20% per day, while experienced workers returning after an absence or facing a sudden heat wave follow a compressed schedule of 50%, 60%, 80%, and 100% over four days (Arbury et al., 2014; NIOSH, 2016; Occupational Safety and Health Administration [OSHA], n.d.).
Finally, heat-related injury deserves its own definition, because it is the category most organizations miss. Heat does not only cause illnesses coded as heat exhaustion or heat stroke. Hot conditions impair attention, judgment, grip, and coordination, raising the risk of falls, cuts, being struck by objects, and vehicle incidents that are rarely attributed to heat in injury records (Park et al., 2021).
Prevalence, Drivers, and Distribution
Globally, the International Labour Organization (ILO) estimates that at least 2.41 billion workers, more than 70% of the global workforce, are exposed to excessive heat at some point in their working lives, and the number of exposed workers grew by 34.7% between 2000 and 2020 because of rising temperatures and labor-force growth (International Labour Organization [ILO], 2024). The ILO attributes 22.87 million occupational injuries and 18,970 deaths each year to excessive workplace heat, along with 2.09 million disability-adjusted life years lost, and links 26.2 million cases of chronic kidney disease worldwide to workplace heat stress (ILO, 2024). These are modeled estimates, but they place heat among the largest occupational hazards on the planet.
In the United States, recorded fatalities are smaller in number but stubborn. Bureau of Labor Statistics (BLS) data show 436 work-related deaths from environmental heat exposure between 2011 and 2021 (U.S. Bureau of Labor Statistics, 2023), 43 in 2022 (OSHA, 2024a), 55 in 2023 (Harris et al., 2025), and 48 in 2024, for an average of about 42 deaths a year from 2011 through 2024 (Congressional Research Service, 2026). Annual counts swing widely, with no sign of a sustained decline. Construction is consistently the most affected sector: it accounted for 34% of heat-related deaths in 2023 while employing about 7% of the workforce, and its heat fatality rate was roughly four times the all-industry rate (Harris et al., 2025). The U.S. Environmental Protection Agency (2024) notes that these counts are likely undercounts because heat is often missed as a contributing cause, deaths occur after workers leave the site, and underreporting is worse in industries that rely on undocumented or short-term workers.
Nonfatal cases are larger but also undercounted. OSHA's proposed rule cites an estimated 33,890 heat-related injuries and illnesses involving days away from work between 2011 and 2020, an average of about 3,389 per year, and 1,054 heat-related cases investigated by OSHA from 2017 to 2022, including 625 hospitalizations and 211 fatalities (OSHA, 2024a). Research using California workers' compensation records, discussed below, suggests that the true toll of heat on injuries is several times larger than these figures imply (Park et al., 2021).
Heat exposure is not confined to fields and rooftops. A 2024 survey of more than 3,500 hourly retail and food service workers found that 45% of indoor workers experience temperatures above 80°F at least sometimes, with regular exposure reported by 63% of warehouse workers, 58% of fast-food workers, and 52% of restaurant workers (Shepherd et al., 2025). Only 24% of indoor workers said their employer had a heat policy, and 41% did not know whether one existed (Shepherd et al., 2025). Kitchens, distribution centers, foundries, laundries, and poorly ventilated stores can all become dangerous during heat waves, especially when air conditioning is undersized, broken, or controlled remotely by a corporate facilities team.
The regulatory landscape shapes how this exposure is managed. OSHA has no heat-specific standard and relies on the General Duty Clause of the Occupational Safety and Health Act, which requires employers to protect workers from recognized serious hazards (Congressional Research Service, 2026). In August 2024, OSHA published a proposed Heat Injury and Illness Prevention in Outdoor and Indoor Work Settings rule that would cover an estimated 36 million workers in general industry, construction, maritime, and agriculture (U.S. Department of Labor, 2024). The proposal would require written heat injury and illness prevention plans and would phase in protections at an initial heat trigger of 80°F heat index and a high heat trigger of 90°F (OSHA, 2024a; Stephens, 2026). The comment period drew more than 43,000 comments, and OSHA held an informal public hearing in June and July 2025 (Congressional Research Service, 2026).
Since then, momentum has shifted. The administration's 2026 regulatory agenda lists a supplemental proposal by December 2026 with final action in 2027 (ISHN, 2026), and the Environmental Defense Fund reports that OSHA plans final action in October 2027, with reports suggesting the protections will be weakened (Stephens, 2026). In July 2026, the House Education and Workforce Committee voted 18 to 15 to advance the Heat Workforce Standards Act (H.R. 6213), which would bar the Department of Labor from finalizing heat protections (Wittenberg, 2026). OSHA's revised heat National Emphasis Program, effective April 2026 for five years, dropped the earlier goal of doubling heat inspections and trimmed its list of targeted industries; from 2022 to 2025, OSHA averaged about 2,400 heat-related inspections a year (American Industrial Hygiene Association [AIHA], 2026; Congressional Research Service, 2026).
States have filled part of the gap. California adopted an outdoor heat standard in 2005 and added an indoor standard in 2024; Washington adopted an outdoor rule in 2008 and updated it in 2023; Oregon and Colorado enacted rules in 2022, the latter covering agriculture only; and Maryland's standard followed in 2024 (Mance, n.d.). Minnesota regulates indoor heat, and Nevada adopted a rule requiring heat exposure analyses and safety plans for larger employers (Lawton, 2025). In April 2026, Virginia's governor signed SB 288, directing the state's Safety and Health Codes Board to adopt indoor and outdoor heat standards, with heat and high-heat procedures, by May 1, 2028 (Esola, 2026). Cities have acted as well: Phoenix requires city contractors to maintain heat safety plans (Littler Mendelson, 2024), and New York City's Executive Order No. 17, signed in June 2026, directs agencies to adopt heat illness plans for municipal workers and to develop guidance for private employers (New York City Office of the Mayor, 2026). The trend is not uniformly protective. Florida enacted a 2024 law barring local governments from requiring employers to provide water, shade, and rest breaks (Moran, 2024).
Internationally, many countries regulate heat more directly. The ILO (2024) documents midday outdoor work bans in Qatar and other Gulf states, Qatar's requirement to stop work above a WBGT of 32.1°C, Spain's 2023 decree requiring heat protections for outdoor workers without loss of pay when work is interrupted, a Greek construction agreement to halt work above 38°C in the shade, and indoor temperature limits in countries including Belgium, Germany, and Latvia. For multinational employers, the question is less whether heat will be regulated than which standard they will choose to apply across their operations.
Organizational and Individual Consequences
Organizational Performance Impacts
The most immediate organizational cost of heat is injury, and the evidence suggests it is far larger than heat illness counts imply. Park, Pankratz, and Behrer (2021) analyzed more than 11 million California workers' compensation claims from 2001 to 2018 and matched them with local weather. They found that hotter days significantly increase workplace injuries, causing roughly 20,000 additional injuries per year in California. The effect appeared not only outdoors but also in indoor settings such as manufacturing and warehousing, and it extended to injury types unrelated to heat illness, such as falls from heights, which the authors attribute to cognitive impairment and fatigue. UCLA's summary of the research reported that days above 90°F carried a 6% to 9% higher injury risk than days in the 50s or 60s, that days above 100°F carried a 10% to 15% higher risk, and that the associated costs in California alone were on the order of $750 million to $1.25 billion a year (UCLA Luskin School of Public Affairs, 2021).
For leaders, the practical implication is that a heat program is also a general injury prevention program. Organizations that track only heat-coded illnesses will underestimate their exposure and may misattribute summer spikes in slips, falls, forklift incidents, or lacerations to individual carelessness rather than to working conditions.
Productivity effects are similarly well documented. Using a national panel of Indian manufacturing plants, Somanathan et al. (2021) found that annual plant output fell by about 2% for each 1°C increase in temperature, driven by reduced worker productivity and increased absenteeism on hot days, and that climate control substantially mitigated these losses. Graff Zivin and Neidell (2014) found that U.S. workers in heat-exposed industries reduce the time they spend working on very hot days. At the global scale, the ILO (2019) projected that heat stress would reduce total working hours by 2.2% by 2030, equivalent to about 80 million full-time jobs and US$2,400 billion in economic losses, with agriculture expected to account for 60% of hours lost and construction for 19%.
Heat also generates legal, financial, and reputational costs. OSHA uses the General Duty Clause to cite employers after heat deaths, and states with standards can levy larger penalties. A 2024 Cal/OSHA willful heat citation against a landscaping company carried a proposed penalty of more than $276,000 (Insurance Journal, 2024). Penalties are often modest relative to the human loss, but enforcement actions draw media attention, union campaigns, and political scrutiny. Labor relations are also affected: heat protections were a prominent issue in the 2023 contract talks between UPS and the Teamsters and in organizing drives among Amazon delivery drivers (Hernandez, 2023; Kaye, 2023). Fast-food workers in California have staged strikes over kitchen temperatures (Garza, 2025). Heat, in other words, has become a bargaining issue and a brand issue as well as a safety issue.
Finally, heat interacts with workforce stability. In tight labor markets for drivers, warehouse associates, cooks, and skilled trades, workers who feel unprotected can and do leave. When acclimatization failures concentrate deaths among new hires, as discussed below, high turnover itself becomes a heat risk factor, creating a cycle in which churn increases danger and danger increases churn.
Individual Wellbeing and Stakeholder Impacts
The individual consequences of heat range from discomfort to death. Among indoor service workers regularly exposed to temperatures above 80°F, 61% reported headaches, 58% fatigue, and 43% nausea in the past year, and 4% reported fainting (Shepherd et al., 2025). Repeated heat strain is associated with kidney damage, and the ILO (2024) highlights chronic kidney disease as a growing occupational health burden in hot regions. Heat also compounds existing cardiovascular conditions, which helps explain why some heat deaths are recorded as cardiac events.
New and returning workers face the highest risk. In a review of 20 heat cases cited by OSHA in 2012 and 2013, 9 of 13 deaths occurred in the worker's first three days on the job, four on the very first day, and none of the employers had an acclimatization program (Arbury et al., 2014). A later review of 25 outdoor cases from 2011 to 2016 found that 11 of 14 fatalities involved workers who were not acclimatized, and that six of the deaths occurred when the heat index was below 91°F, a level OSHA guidance had treated as lower risk (Tustin et al., 2018). OSHA now summarizes the evidence by noting that almost half of heat-related deaths occur on a worker's first day and more than 70% during the first week (OSHA, n.d.).
The burden falls unequally. Park et al. (2021) found that heat-related injury risk was substantially higher for lower-income workers, men, and younger workers, suggesting that workplace heat widens existing compensation inequality; UCLA's summary reported that workers in the lowest income tier were about five times more likely to be affected than those in the highest (UCLA Luskin School of Public Affairs, 2021). Migrant and temporary workers face particular hazards. In 2023, a 26-year-old worker who had come to Florida under the H-2A agricultural visa program died of heatstroke four days after starting work cutting sugar cane in a field 20 minutes from the nearest road (OSHA, 2024b). Workers with limited English proficiency, precarious immigration status, or piece-rate pay may be reluctant to slow down, take breaks, or report symptoms. Women and nonbinary workers in indoor service jobs reported feeling overheated more often than men, and workers facing economic hardship reported more exposure (Shepherd et al., 2025).
Families and communities bear the downstream costs: lost income, medical bills, disability, and grief. Customers and the public are also stakeholders, since heat-fatigued drivers, health care workers, and equipment operators can endanger others. And investors increasingly view unmanaged physical climate risk to workers as a governance concern, with trade associations and investor groups urging companies to adopt protections without waiting for regulation (Stephens, 2026).
Evidence-Based Organizational Responses
Research and enforcement experience point to a consistent set of controls that prevent heat illness and injury. NIOSH (2016) and the ILO (2024) both emphasize combining engineering controls, administrative controls such as acclimatization and work-rest cycles, training, and personal measures within a written program, and OSHA's enforcement reviews show that deaths tend to occur where those elements are absent (Arbury et al., 2014). Table 1 summarizes five responses that leaders can adopt now, regardless of how federal rulemaking unfolds. Responses typically scale as heat rises, and how they map onto the hierarchy of controls.
Table 1: Evidence-Based Organizational Responses to Occupational Heat Stress
Response | Evidence Base | Key Practices | Illustrative Examples |
Heat Plans and Triggers | OSHA enforcement reviews; state standards; proposed federal rule | Written plan, named owner, heat-index or WBGT triggers, high-heat procedures, emergency response | Parkwood Landscape Maintenance; McNeill Labor Management; City of Phoenix contractors |
Acclimatization and Water, Rest, Shade | NIOSH criteria; MMWR reviews of fatalities | 20% ramp for new workers, cool water, shade, paid recovery breaks, right to rest | Weathercraft; Fair Food Program growers |
Scheduling and Shift Redesign | ILO country practices; Indian manufacturing evidence | Earlier starts, midday pauses, route and quota adjustments, task rotation | U.S. Postal Service; Amazon delivery network |
Engineering Controls and Cooling | Productivity and climate-control studies; ILO guidance | Vehicle and building cooling, ventilation, insulation, shade structures, maintained AC | UPS; McDonald's and El Pollo Loco kitchens |
Heat-Aware Supervision, Voice, and Monitoring | AIHA white paper; worker surveys; complaint mechanisms | Supervisor training, buddy checks, complaint lines, optional wearables with privacy safeguards | Perrigo; Cardinal Glass; United Cleanup Oak Ridge; Fair Food Program |
Heat Illness Prevention Plans and Heat-Index Triggers
The foundational response is a written heat illness prevention plan that specifies who is responsible, how heat conditions will be monitored, what actions are triggered at which thresholds, and how emergencies will be handled. When OSHA reviewed its heat enforcement cases from 2012 and 2013, it found that 12 of the 18 cited private employers and federal agencies had no heat illness prevention program at all, none had a complete program, 13 did not use the heat index or a similar heat-risk approach, and only one used scheduled work-rest cycles (Arbury et al., 2014). The absence of a plan is therefore not a paperwork gap; it is the common denominator of fatal cases.
Most U.S. standards now use temperature or heat-index triggers to structure the plan. Oregon and Maryland require water and shade at a heat index of 80°F and add high-heat practices at 90°F; Washington's outdoor rule begins at 80°F for most clothing and as low as 52°F for workers in nonbreathable clothing, with paid cool-down rest of 10 minutes per hour at 90°F and 15 minutes per hour at 100°F; and California's indoor standard requires controls at a heat index of 87°F, or 82°F where workers wear restrictive clothing or face high radiant heat (Lawton, 2025). OSHA's proposed rule uses initial and high heat triggers of 80°F and 90°F (OSHA, 2024a). The evidence suggests these thresholds are not overly cautious: Tustin et al. (2018) found that a substantial share of fatal cases occurred at a heat index below 91°F and proposed 85°F as a screening threshold where WBGT data are unavailable. A plan should also account for factors that raise risk at a given temperature, including direct sun, radiant heat from ovens or furnaces, protective clothing, heavy work, and new or returning workers.
Effective approaches:
Named ownership: Assign a specific manager at each site who is accountable for monitoring forecasts and on-site conditions and for activating heat procedures.
Tiered triggers: Define what changes at the initial, high, and extreme heat levels, and use the most protective standard among the jurisdictions where you operate.
Site-level measurement: Supplement forecasts with on-site heat index or WBGT readings, especially indoors, where weather reports do not reflect conditions near ovens, dock doors, or furnaces.
Emergency readiness: Specify how a worker with symptoms will be cooled immediately and transported, including at remote sites far from roads or hospitals.
Language access: Deliver the plan and training in languages workers understand, as the proposed federal rule and many state standards require (Stephens, 2026).
Contractor coverage: Extend plan requirements to subcontractors and labor contractors who work under your control.
Parkwood Landscape Maintenance in Van Nuys, California, illustrates the cost of operating without a functioning plan. In 2024, Cal/OSHA found that the company's employees worked outdoors without required water, shade, or heat illness training, that the company had no written procedures for high-heat conditions that sometimes exceeded 95°F, and that employees had to buy their own drinking water (Insurance Journal, 2024). Because the company had been cited for heat violations in 2022, Cal/OSHA classified the new violation as willful and proposed penalties of $276,425 (Insurance Journal, 2024).
McNeill Labor Management, a farm labor contractor in Belle Glade, Florida, was cited by OSHA in 2024 after an H-2A worker collapsed and died of heatstroke while stacking sugar cane at a heat index of 97°F on his fourth day on the job (OSHA, 2024b). OSHA's area director said that acclimatization and required rest breaks might have prevented the death, and OSHA proposed $27,655 in penalties for exposing workers to high ambient heat and for failing to report the hospitalization and death; the company contested the findings (OSHA, 2024b). The case shows how plan elements interact: a remote worksite 22 miles from the hospital made emergency planning as critical as prevention.
The City of Phoenix offers a public-sector model for extending plan requirements through procurement. In March 2024, the city council unanimously required all city contractors and subcontractors to maintain written heat safety plans that provide cool drinking water, breaks as needed, shade or air conditioning, effective acclimatization practices, and training on heat illness symptoms, first aid, and reporting, with air-conditioned enclosed vehicle cabs required by May 2025 (Littler Mendelson, 2024). Noncompliant contractors can lose city contracts or be suspended or debarred (Littler Mendelson, 2024).
A common pitfall: treating the plan as a compliance binder rather than an operating procedure. Plans that are written once, filed, and never activated provide little protection. The test is whether a frontline supervisor on a 95°F afternoon knows exactly what changes and has the authority and resources to make it happen.
Acclimatization and "Water, Rest, Shade"
OSHA's long-running public campaign reduces heat prevention to three words: water, rest, shade. The underlying evidence is strong. NIOSH (2016) recommends that workers in moderate heat drink about one cup of water every 15 to 20 minutes rather than waiting until they are thirsty, that recovery breaks be taken in cool or shaded areas, and that workers be acclimatized gradually over 7 to 14 days. State standards commonly require at least 32 ounces of water per worker per hour and shade at the initial trigger (Lawton, 2025). The enforcement record is equally clear about the stakes of skipping acclimatization: across OSHA's reviews, failure to acclimatize was the most common deficiency and the factor most clearly associated with death (Arbury et al., 2014; Tustin et al., 2018).
Rest is the element most often undermined in practice. Workers paid by the piece, measured against hourly delivery quotas, or worried about being seen as weak frequently skip breaks. That is why several standards require rest breaks to be paid and why NIOSH (2016) recommends reducing workload and using a buddy system rather than relying on workers to self-select rest under pressure. Acclimatization also needs to cover more than new hires. Experienced workers returning from vacation, illness, or a cooler assignment, and entire crews facing an early-season heat wave, lose tolerance and need a compressed ramp-up (Arbury et al., 2014).
Effective approaches:
Structured ramp-up: Limit new workers to 20% of a normal shift in the heat on day one and increase by no more than 20% per day, with close supervision for the first two weeks (NIOSH, 2016; OSHA, n.d.).
Returning-worker protocol: Apply a 50-60-80-100% schedule for experienced workers after a week or more away or at the start of a heat wave (NIOSH, 2016).
Water at the point of work: Place cool water close enough that drinking does not require leaving the task for long, and replenish electrolytes during prolonged sweating.
Mobile shade and cool rest areas: Provide shade that moves with crews and cooled rest areas indoors.
Protected, paid recovery: Make rest breaks paid, scheduled at high heat, and available on request at any time without penalty.
Weathercraft, a roofing contractor in Jefferson City, Missouri, was cited by OSHA under the General Duty Clause after a 47-year-old laborer collapsed from heat stroke on his third day on the job; his core body temperature exceeded 107°F, and investigators estimated the heat index at about 90°F when he collapsed (Gonzalez, 2016). OSHA's acting area director said the death underscored the need for employers to ensure workers are acclimated, and the agency proposed $12,471 in penalties (Gonzalez, 2016). The case mirrors the national pattern: a new worker, a moderate heat index, and no ramp-up.
Growers participating in the Fair Food Program, a worker-driven social responsibility program founded in 2011 by the Coalition of Immokalee Workers, operate under heat protections that go beyond what Florida law requires. Participating farms must provide shade from portable structures that move with crews, water with electrolytes, a rest break every two hours from April through November, crew leaders trained to watch for heat illness among workers who are still acclimating, and the right for workers to stop and rest or seek care when they have symptoms (Moran, 2024). The protections are legally binding on participating growers, are audited by an independent council that also runs a 24-hour complaint line, and are backed by purchasing commitments from 14 major food retailers (Moran, 2024). The program demonstrates that water, rest, and shade can be enforced through supply chain contracts even where state law prohibits local mandates.
A common pitfall: providing water and shade but not the time to use them. When quotas, piece rates, or route targets remain unchanged on hot days, workers will often forgo breaks. Leaders need to adjust performance expectations whenever heat procedures are activated, or the procedures will exist mainly on paper.
Work Scheduling and Shift Redesign
Because heat load depends on both environmental conditions and metabolic workload, when and how fast work is done matters as much as where it happens. The ILO (2024) identifies rescheduling heavy work to cooler hours, rotating workers through hot tasks, and longer or more frequent breaks as core administrative controls. Many countries now codify scheduling. Qatar bans outdoor work from 10 a.m. to 3 p.m. between June and mid-September, China caps outdoor work hours between 37°C and 40°C and stops it above 40°C, and Spain's construction collective agreement allows unions to propose hours that avoid peak sun (ILO, 2024). These approaches recognize that reducing exposure time is often more reliable than asking workers to endure the hottest hours with better equipment.
The productivity evidence supports the business case. If output per hour falls sharply on hot days (Somanathan et al., 2021), shifting demanding tasks to cooler periods may recover much of that lost output while reducing risk. Schedule redesign is not costless: early starts can collide with childcare, transit schedules, and noise ordinances, and night work brings its own fatigue risks. But it is one of the few controls that can be implemented quickly and at modest capital cost.
Effective approaches:
Heat-shifted start times: Move heavy outdoor work to early morning or evening during heat advisories, with advance notice to workers.
Quota and route adjustment: Reduce delivery stops, production targets, or piece-rate expectations when high heat procedures are active.
Task rotation: Rotate workers between hot and cooler tasks, such as alternating oven stations with prep or dock work with indoor sorting.
Planned stand-downs: Define conditions under which nonessential outdoor work stops, with pay protection where feasible, as Spain and Greece have done (ILO, 2024).
Seasonal workforce planning: Plan staffing so that hot-season peaks do not depend heavily on new, unacclimatized hires.
The U.S. Postal Service illustrates how scheduling becomes an enforcement remedy. After letter carrier Eugene Gates Jr. collapsed and died while delivering mail in Dallas in June 2023, on a day when the heat index reached as high as 113°F, OSHA cited the Postal Service for failing to protect workers from the recognized hazard of high outdoor heat and proposed a $15,625 penalty (Scientific American, 2023). The abatement measures OSHA identified included ensuring all employees were trained under the Postal Service's own Heat Illness Prevention Program, allowing rest breaks and water, and starting deliveries earlier on hot days (Scientific American, 2023). An E&E News investigation found that Gates was one of potentially thousands of carriers who had not received the heat training required by Postal Service policy (Scientific American, 2023), a reminder that a policy on paper does not substitute for implementation.
Amazon's delivery network shows both the promise and the limits of route adjustment. Amazon told NPR in 2023 that it had adjusted some delivery routes the previous year so drivers could take more cooling breaks (Kaye, 2023). Yet drivers employed by Amazon's independent delivery contractors described routes of around 300 packages at roughly 25 stops per hour on days above 100°F, broken van air conditioning, and repair delays they attributed to Amazon, which in turn said that contractors were responsible for repairs (Kaye, 2023). The example highlights a structural problem: when work is organized through subcontractors, schedule and workload decisions made by the lead firm may determine heat exposure even when legal responsibility is diffuse.
A common pitfall: shifting hours without shifting workload. Starting earlier helps only if the volume of work expected in the hottest hours also falls. Organizations that move start times but keep the same quotas often push the most strenuous work into the afternoon peak anyway.
Engineering Controls and Cooling
Engineering controls reduce heat at the source and therefore sit higher in the hierarchy of controls than procedures or personal measures. They include air conditioning and evaporative cooling, ventilation and fans, insulation and reflective roofing, shielding from radiant sources, shade structures, mechanization of heavy tasks, and cooled vehicle cabs and break rooms (ILO, 2024). The ILO (2024) highlights mechanization as a simple, evidence-based way to reduce metabolic heat, and notes that indoor environments are easier to regulate precisely because employers can control them. Evidence from manufacturing suggests that climate control significantly reduces heat-related productivity losses (Somanathan et al., 2021), which means cooling investments can be justified on operational as well as safety grounds.
Indoor workplaces illustrate the gap between availability and control. In the Shift Project survey, 84% of indoor service workers had access to water, but only about 12% could adjust air conditioning themselves and fewer than 10% could leave early in extreme heat; many described thermostats controlled by corporate offices or maintenance teams and cooling off in walk-in freezers or their cars (Shepherd et al., 2025). An engineering control that cannot be adjusted, repaired, or escalated quickly offers less protection than its specification suggests.
Effective approaches:
Cooling audits: Map heat sources and cooling capacity for every site and vehicle class, prioritizing kitchens, docks, mezzanines, cabs, and cargo areas.
Maintenance as safety: Treat broken air conditioning or ventilation during hot weather as an urgent safety repair with a defined response time, not a routine ticket.
Fleet specifications: Specify cooling, heat shields, and airflow in vehicle procurement, and deploy cooled vehicles to the hottest regions first.
Local control: Give site managers authority and budget to add portable cooling, fans, or shade during heat events without corporate approval delays.
Mechanization and redesign: Reduce manual lifting and other high-metabolic tasks in hot environments where feasible.
UPS agreed in June 2023, during contract negotiations with the Teamsters covering more than 340,000 workers, to install air conditioning in all small package delivery vehicles purchased after January 1, 2024, a category that makes up about 95% of its delivery fleet (Hernandez, 2023). The company also agreed to install cab fans in existing package cars within 30 days of ratification, add heat shields to reduce floor temperatures, and fit air induction systems to increase airflow in cargo areas, and said it would send new vehicles to the hottest regions first where possible (Hernandez, 2023). The agreement followed reports that more than 100 UPS workers had been treated for heat illness over four years and the death of a young driver in California in 2022 (Hernandez, 2023; Kaye, 2023). Because the air conditioning commitment applies to new purchases, the fleet will turn over gradually, a reminder that engineering solutions often need interim administrative measures.
Fast-food kitchens show what happens when cooling fails. A 2025 Service Employees International Union report summarized by Grist found that three in five fast-food workers reported excessive heat in their restaurants and four in five reported problems with air conditioning (Garza, 2025). Workers at a McDonald's near San Jose, California, struck after kitchen temperatures rose above 100°F, and a shift manager described an old, undersized air conditioning system; workers at a San Jose El Pollo Loco staged a two-day walkout after the restaurant reached 90°F (Garza, 2025). California's indoor standard requires additional controls once indoor heat index reaches 87°F, but advocates told Grist that enforcement remains weak (Garza, 2025).
A common pitfall: treating cooling as a capital project rather than a reliability commitment. Installing equipment matters less than keeping it working on the hottest days, when demand on aging systems is highest and repair crews are busiest.
Heat-Aware Supervision, Worker Voice, and Monitoring
Even the best plan depends on people noticing early warning signs and acting on them. NIOSH (2016) recommends training workers and supervisors to recognize symptoms, using a buddy system, and closely observing new workers during their first two weeks. Heat illness can impair judgment, so the affected worker is often the last to recognize danger. Supervisors also control the informal signals that determine whether a worker feels safe asking for a break. Training that emphasizes symptoms without changing supervisory incentives tends to have limited effect.
Worker voice is the complement to supervision. Workers often know first when a cooler is broken, a route is unworkable, or a new colleague is struggling. Programs that give workers a protected right to stop and an independent channel to report problems, such as the Fair Food Program's complaint line (Moran, 2024), translate that knowledge into action. Indoor service workers who reported having an employer heat policy often said it was not enforced during peak workloads or short staffing (Shepherd et al., 2025), underscoring the need for feedback loops that reach decision-makers.
Wearable physiological monitoring is a newer tool. Devices that estimate core body temperature, heart rate, and physiological strain can account for individual variation in response to the same heat load and can inform decisions to modify or stop work (AIHA, 2024). But the evidence on accuracy in dynamic workplaces remains limited, and humidity, activity, clothing, and individual characteristics can produce false positives and false negatives (AIHA, 2024; Bussewitz, 2024). AIHA (2024) recommends that monitoring supplement an existing heat stress management plan, that devices be validated as fit for purpose, that participation rest on informed consent and clear data-use agreements, and that workers never be penalized for rest that monitoring indicates they need. Labor and privacy advocates have warned that physiological data could be used for discipline, health plan decisions, or to override a worker's request for a break, and have urged opt-in participation, minimal data processing, and rapid deletion (Bussewitz, 2024).
Effective approaches:
Supervisor heat competence: Train supervisors to recognize early symptoms, activate high-heat procedures, and respond to rest requests without penalty.
Buddy systems and check-ins: Pair workers at high heat and schedule regular check-ins for isolated workers such as drivers and solo technicians.
Protected stop-work authority: Make clear that any worker may stop and cool down when experiencing symptoms, and back that commitment through discipline and incentive policies.
Independent reporting channels: Provide multilingual, confidential ways to report heat hazards, and close the loop on fixes.
Privacy-first monitoring: If using wearables, make participation voluntary, limit data to safety use, delete it promptly, and involve workers or their representatives in design.
Perrigo, a consumer products company, outfitted more than 100 employees at its infant formula plants with armbands from SlateSafety that estimate core body temperature, with alerts set at 101.3°F (Bussewitz, 2024). Cardinal Glass purchased five armbands, software, and air-monitoring equipment for furnace masons and told the Associated Press that two prior heat-related emergency room visits costing $15,000 justified the investment (Bussewitz, 2024). United Cleanup Oak Ridge, a U.S. Department of Energy contractor performing nuclear facility cleanup in Tennessee, reported a significant decrease in workers needing medical attention after adopting the devices, and its safety manager said sensor data had led some employees to physicians who identified previously unknown heart conditions (Bussewitz, 2024). These are company-reported outcomes rather than controlled evaluations, and NIOSH researchers quoted in the same report cautioned that device accuracy needs more study (Bussewitz, 2024).
New York City's Executive Order No. 17 approaches voice and awareness at the scale of a municipal employer. It directs the city's health department, emergency management agency, and administrative services department to develop multilingual heat guidance for employees, contractors, gig workers, and day laborers; requires mayoral agencies to implement indoor and outdoor heat illness plans for city workers during heat emergencies; and calls for a review of city workers' compensation claims to identify temperature-related patterns (New York City Office of the Mayor, 2026). Using claims data to find hidden heat injuries reflects the research finding that heat raises injury risk well beyond heat-coded illnesses (Park et al., 2021).
A common pitfall: using monitoring as a substitute for authority. A wearable that alerts a worker to rising strain is of little value if the worker cannot stop, has no cool place to go, or fears the data will be used against them. As one environmental health advocate told the Associated Press, devices are of little use without access to water and time to drink it (Bussewitz, 2024).
Building Long-Term Climate-Adaptive Workforce Capability
The five responses above can reduce harm this summer. Building durable capability requires leaders to treat heat as a permanent feature of the operating environment rather than a seasonal anomaly. Three capabilities matter most.
Embedding Heat Into Enterprise Risk and Workforce Planning
Heat should sit in the enterprise risk register alongside other physical climate risks, with a named executive owner, metrics, and board visibility. That means tracking not only heat illnesses but also total injury rates on hot days, absenteeism, turnover, productivity, and claims costs by temperature, following the logic of research showing that heat drives injuries beyond heat illness (Park et al., 2021) and New York City's plan to mine claims data for hidden patterns (New York City Office of the Mayor, 2026). Organizations operating across several states can reduce complexity by adopting a single internal standard pegged to the most protective jurisdiction in which they operate, rather than managing a different playbook for each state. Given that Virginia's standard will not be finalized until 2028 (Esola, 2026) and the federal rule remains uncertain (Stephens, 2026), an internal standard also hedges against regulatory change in either direction.
Workforce planning should incorporate heat as well. Because unacclimatized workers account for a large share of deaths (Arbury et al., 2014; Tustin et al., 2018), hiring surges timed to the hottest months, heavy reliance on temporary staff, and high turnover all raise risk. Leaders can stagger seasonal hiring, build acclimatization time into onboarding budgets, retain experienced crews through the hot season, and set heat-adjusted productivity standards that do not penalize managers for protecting workers.
Designing Work and Workplaces for a Hotter Baseline
Long-term adaptation means designing heat out of work. Capital planning for new facilities, retrofits, and fleets should assume more frequent and severe heat waves, with cooling, ventilation, insulation, and shade specified from the outset rather than added after a crisis. Engineering decisions made today, such as UPS's commitment to air-conditioned vehicles (Hernandez, 2023) or Phoenix's requirement for air-conditioned contractor cabs (Littler Mendelson, 2024), will shape exposure for a decade or more. Work design is equally important: mechanizing heavy tasks, redesigning routes, building flexibility into delivery promises, and creating schedules that can shift during heat events are structural choices, not emergency measures (ILO, 2024).
Research suggesting that the heat sensitivity of injuries declined in California over two decades indicates substantial room to adapt with existing technologies and practices (Park et al., 2021). The organizations that capture that potential will be those that treat thermal conditions as a design parameter for jobs, much as ergonomics became a design parameter for workstations.
Sharing Accountability Across Supply Chains and Communities
Many of the workers most exposed to heat are not employed directly by the firms that shape their working conditions: farmworkers hired through labor contractors, delivery drivers employed by independent service partners, and construction crews working for subcontractors. Durable protection therefore depends on extending heat standards through contracts, procurement, and supplier codes of conduct. The Fair Food Program shows how buyer commitments can make water, rest, and shade enforceable on farms (Moran, 2024), and Phoenix shows how a public buyer can do the same for its contractors (Littler Mendelson, 2024). Trade groups have also begun issuing heat stress toolkits and urging companies to act without waiting for regulation (Stephens, 2026).
Accountability also runs through labor relations and community partnerships. Collective bargaining has produced some of the most concrete heat commitments in U.S. logistics (Hernandez, 2023), and worker organizations are often best placed to identify failures early. Partnerships with local public health agencies, emergency management offices, and community organizations can help employers reach workers with limited English proficiency, coordinate with heat emergency plans, and connect workers to cooling resources. Leaders who share data, invite worker input, and coordinate across organizational boundaries will build more credible and effective protections than those who manage heat in isolation.
Conclusion
Extreme heat has moved from an occasional disruption to a defining condition of work in much of the United States and the world. The evidence is consistent across sources: heat kills dozens of U.S. workers each year and likely more than recorded, injures many thousands more through pathways that rarely appear in heat illness statistics, reduces productivity, and falls hardest on new, low-wage, migrant, and subcontracted workers. Federal rulemaking may be delayed or weakened, but the hazard will not wait, and a growing patchwork of state, local, and international rules means that well-run organizations will need a coherent heat strategy regardless.
The core of that strategy is not mysterious. Deaths cluster where employers lack plans, skip acclimatization, and fail to provide water, rest, and shade. Organizations that write and activate tiered heat plans, protect new workers, reschedule demanding work, invest in reliable cooling, and train supervisors to act on early signs while giving workers real authority to stop can prevent most serious outcomes. The examples in this article, from penalties against contractors who left workers without water to binding protections negotiated by unions and buyers, show both the cost of inaction and the feasibility of protection.
The deeper leadership task is to build climate-adaptive workforce capability: integrating heat into risk management and workforce planning, designing work and workplaces for a hotter baseline, and extending accountability through supply chains and communities. Leaders who do this will protect their people, stabilize their operations, and be ready for whatever standards eventually emerge.
Act before the rule: Adopt an internal heat standard at least as protective as the strictest jurisdiction in which you operate, using initial and high heat triggers around 80°F and 90°F heat index.
Protect the first week: Build a 20% daily acclimatization ramp into onboarding and return-to-work processes, since most heat deaths occur early in a job.
Make rest real: Provide water, shade, and paid recovery breaks, and adjust quotas and targets whenever heat procedures are active.
Fix the environment: Prioritize reliable cooling, ventilation, and vehicle air conditioning, and treat broken cooling as an urgent safety repair.
Measure the hidden toll: Track injuries, absences, and claims against temperature, not just heat-coded illnesses.
Empower and protect workers: Train supervisors, guarantee stop-work rights, provide independent reporting channels, and use wearables only with voluntary participation and strict privacy safeguards.
Extend protection through contracts: Require heat plans from contractors, labor providers, and suppliers, and support them in meeting those requirements.
Research Infographic
References
American Industrial Hygiene Association. (2024). Wearable physiological monitoring to assess heat strain in response to heat exposure [White paper]. AIHA.
American Industrial Hygiene Association. (2026, April 16). OSHA updates national emphasis program for heat hazards. AIHA News.
Arbury, S., Jacklitsch, B., Farquah, O., Hodgson, M., Lamson, G., Martin, H., & Profitt, A. (2014). Heat illness and death among workers: United States, 2012–2013. Morbidity and Mortality Weekly Report, 63(31), 661–665.
Bussewitz, C. (2024, August 24). Sensors can read your sweat and predict overheating. Here's why privacy advocates care. Associated Press.
Congressional Research Service. (2026). Occupational Safety and Health Administration (OSHA) regulation of employee exposure to heat (CRS Insight IN11701). Congressional Research Service.
Esola, L. (2026, April 15). Virginia governor signs workplace heat illness prevention bill. Business Insurance.
Garza, F. (2025, August 29). Workers are facing dangerous heat, even inside fast-food restaurants. Grist.
Gonzalez, G. (2016, November 11). Heat-related death leads to OSHA citation for roofing contractor. Business Insurance.
Graff Zivin, J., & Neidell, M. (2014). Temperature and the allocation of time: Implications for climate change. Journal of Labor Economics, 32(1), 1–26.
Harris, W., Trueblood, A., Dufoe, D., Brooks, R. D., West, G., & Roelofs, C. (2025). Heat injuries and illnesses among construction workers [Data bulletin]. CPWR, The Center for Construction Research and Training.
Hernandez, J. (2023, June 14). UPS workers facing extreme heat win a deal to get air conditioning in new trucks. NPR.
Insurance Journal. (2024, December 18). Cal/OSHA issues $276K citation for serious heat violations. Insurance Journal.
International Labour Organization. (2019). Working on a warmer planet: The impact of heat stress on labour productivity and decent work. International Labour Office.
International Labour Organization. (2024). Ensuring safety and health at work in a changing climate. International Labour Office.
ISHN. (2026, July 15). New regulatory agenda updates OSHA standards action. Industrial Safety & Hygiene News.
Kaye, D. (2023, July 20). Delivery drivers want protection against heat, but it's an uphill battle. NPR.
Lawton, B. (2025). Statewide laws to protect workers from extreme heat. Network for Public Health Law.
Littler Mendelson. (2024). Phoenix City Council requires heat safety plans for city contractors. Littler Mendelson P.C.
Mance, A. A. (n.d.). Extreme heat injury and illness prevention standards. Environmental, Social, Governance and Sustainability Newsletter. American Bar Association Section of Environment, Energy, and Resources.
Moran, G. (2024, March 20). Florida banned heat protections. This partnership offers a solution. Civil Eats.
National Institute for Occupational Safety and Health. (2016). Criteria for a recommended standard: Occupational exposure to heat and hot environments (DHHS [NIOSH] Publication No. 2016-106). U.S. Department of Health and Human Services.
New York City Office of the Mayor. (2026). Executive Order No. 17: Protecting workers from extreme heat. City of New York.
Occupational Safety and Health Administration. (n.d.). Protecting new workers. U.S. Department of Labor.
Occupational Safety and Health Administration. (2024a). Heat injury and illness prevention in outdoor and indoor work settings (Proposed rule; Docket No. OSHA-2021-0009). Federal Register, 89(169).
Occupational Safety and Health Administration. (2024b, April 15). [News release regarding citations issued to McNeill Labor Management Inc., Belle Glade, Florida]. U.S. Department of Labor.
Park, R. J., Pankratz, N., & Behrer, A. P. (2021). Temperature, workplace safety, and labor market inequality (IZA Discussion Paper No. 14560). IZA Institute of Labor Economics.
Scientific American. (2023). Heat-related death of postal worker leads to controversial fine. Scientific American (reprinted from E&E News).
Shepherd, H., Harknett, K., & Jackson, H. (2025). Heat exposure in indoor service sector workplaces: Prevalence, health consequences, and mitigation strategies. The Shift Project.
Simon, M. (2026, September 16). Yes, this summer really was as hot as you think it was. Grist.
Somanathan, E., Somanathan, R., Sudarshan, A., & Tewari, M. (2021). The impact of temperature on productivity and labor supply: Evidence from Indian manufacturing. Journal of Political Economy, 129(6), 1797–1827.
Stephens, E. (2026, September 22). Deadly temperatures spotlight workers' need for heat protection rules. Climate 411, Environmental Defense Fund.
Tustin, A. W., Lamson, G. E., Jacklitsch, B. L., Thomas, R. J., Arbury, S. B., Cannon, D. L., Gonzales, R. G., & Hodgson, M. J. (2018). Evaluation of occupational exposure limits for heat stress in outdoor workers: United States, 2011–2016. Morbidity and Mortality Weekly Report, 67(26), 733–737.
U.S. Bureau of Labor Statistics. (2023). 36 work-related deaths due to environmental heat exposure in 2021. The Economics Daily.
U.S. Department of Labor. (2024, August 30). [News release announcing publication of the proposed heat injury and illness prevention rule].
U.S. Environmental Protection Agency. (2024). A closer look: Heat-related workplace deaths. Climate Change Indicators.
UCLA Luskin School of Public Affairs. (2021, July 16). High temperatures increase workers' injury risk, whether they're outdoors or inside. UCLA Luskin News.
Wittenberg, A. (2026, July 22). Panel advances bill to kill worker heat protections. E&E News.
Jonathan H. Westover, PhD, Chief Research Officer (Nexus Institute for Work and AI); Co-Founder & Chief Workforce and Learning Officer (Future State University); Founder & CEO (Human Capital Innovations); Professor of Organizational Leadership & Change (UVU). Read Jonathan Westover's executive profile here.
Suggested Citation: Westover, J. H. (2026). Working in the Heat: Leading Workforces Through Rising Temperatures and Unsettled Heat Rules. Human Capital Leadership Review, 40(4). doi.org/10.70175/hclreview.2020.40.4.2
