politics

There are many outrage responses here, e.g., because they're evil. The outrage is understandable, but simply ascribing this to evil isn't completely accurate or helpful beyond a little catharsis. There's logic to their actions, and they're making these choices because their donors value profit over the safety and quality of life of their employees. That's the evil. Let me explain the logic since it's one of my areas of expertise.

Tl;dr: complying with reasonable regulations would be more expensive, and that expense will increase as climate change accelerates. Public knowledge of workplace heat safety is generally poor, humans are extremely heat adaptable, and regulations are vague, allowing for significant employer abuse.

The Regulatory Landscape is a Desert
Pun intended. 

Federal OSHA regulations don't cover heat. Full stop. While OSHA has released guidance for working in high temperature conditions, it's entirely optional and unenforceable as no heat specific regulation exists. All enforcement falls under the General Duty Clause, which calls for employers to make a good-faith effort to provide a workplace free from recognized hazards that may cause death or serious injury. This vagueness is intended and actually beneficial as it acts as a catch-all for unregulated edge cases, but falls flat for more complex, consistent issues... like heat. This would be fine in a functional, rational government as the pertinent regulations would simply be added, but look where we're at. 2026. Yeah.

"Heat" is Complex
It often comes as a surprise to the sedantary American public, but humans handle working at high temperatures exceptionally well - more about that later. That same public is quite bad at understanding what constitutes "too hot" as the reality is complex. The best indicator is the wet-bulb globe temperature (WBGT), which accounts for air temperature, humidity, sun angle, cloud cover, air pressure, and wind, and can be adjusted for clothing/PPE type. Based on the intensity of work and environmental conditions, a crew could safely work at 110°F or more in one location but cap out at 75°F or less in another. 

Humans are Great with Heat
Humans are amongst the most heat adaptable animals on the planet. Reasonably physically fit people with appropriate clothing and PPE, unlimited cool water, a shaded or air conditioned rest area, two weeks of progressive acclimation, and sufficient rest breaks can perform 8-10 hour shifts doing even heavy physical labor in hot temperatures with a large safety margin of error. With the right PPE and controls (huge fuck off fans or, God forbid, AC), they can even be reasonably comfortable.

Companies Maximize Profit Based on Human Adaptability and Regulatory Insufficiency
Ideal safety regulations take into account the condition of the average worker, build in a significant margin of error, and plainly describe requirements. Employers would be held to a consistent standard based on metrics like WBGT, and as average WBGT increases, so would their expenses. Based on my industry experience, many employers are ignorant of industry best practices while others simply ignore them, so the cost to meet and maintain regulatory standards would be significant, particularly as the frequency of worker downtime should increase in conjunction with temperature - the thing that keeps going up every year.

In our current, barren regulatory landscape, some employers avoid expense by employee self-selection, where those unable to handle the literal heat quit, and relying on plausible deniability and pleading ignorance in the event of an incident. OSHA fines have historically been fairly low, infrequent due to the lack of clear, specific regulation, and are increasingly less common as OSHA continues to lose funding and staffing over time despite a growing workforce. The math usually works in the employer's favor: those prone to injury tend to quit, those who remain can typically be pushed without injury beyond the conditions regulations would enforce, and the costs of heat-related illness and possible fines are often much less than a comprehensive, effective, and humane heat mitigation program.