High temperatures and recent heat waves affected some 2.4 billion workers worldwide.

But in the U.S., says the International Labour Organization’s Halshka Graczyk, efforts to protect construction workers, farm workers, warehouse workers and others are “a success story.”

At the industry and company levels, Graczyk sees momentum in adding air conditioning to transport vehicles and requiring scheduled rest breaks for workers who do jobs outside in the heat. (Forbes reports that a new contract negotiated by the Teamsters Union and UPS  will result in trucks being equipped with air conditioning, heat shields or fans.)

In recent years, cities and states, often called the “laboratories of democracy,” have adopted standards that kick in with higher temperatures or heat indexes. And federal workplace rules protecting workers from heat may be on the horizon (the rulemaking process takes time and does not always end with enactment).

Phoenix, where temperatures average 38 degrees in summer months, this year passed an ordinance that ensures that its construction, engineering and airline workers toiling outside have access to shade, drinking water and time for rest. What’s more, these Phoenix workers are trained to identify signs of heat stress on the body.

“This heat safety ordinance will change my life and the lives of my coworkers,” said Filiberto Lares, a food-service worker for an airline in Phoenix. In Colorado, temperatures between 27 degrees and 35 degrees trigger particular requirements to protect farm workers.

“We are ensuring that our agricultural workers have the necessary equipment and breaks to continue their important work,” says a spokesperson for the state’s labour department. Colorado requires employers to teach workers to quickly address any heat-related health situation.

Ryan Allen, of Washington State’s Department of Labor & Industries, says workers’ ability to self-identify and prevent symptoms of heat-related illness is essential. California, Minnesota, Oregon and Washington state have their own standards.

And Maryland is likely to follow, according to the National Caucus of Environmental Legislators. Meanwhile, the Biden administration is advancing a nationwide safety standard.

A rule is being promulgated through the U.S. Occupational Safety and Health Administration, the Labor Department’s arm that requires employers to provide workplaces free from hazards likely to cause serious physical harm or death. The proposed rule would trigger two levels of action if the heat index (a combination of temperature and humidity) reaches 27 or 32 degrees.

Broadly, under either trigger, workers would be assured access to cool water; a break space with shade or air conditioning; and would receive training to recognize the signs of heat illness. The higher heat index would require more frequent breaks and buddy systems so that workers and their supervisors watch over each other’s condition.

“This new rule will substantially reduce heat injuries, illnesses and deaths for over 36 million workers,” President Biden said on July 2.