For years, researchers have raised the alarm about the dangers of extreme heat in the workplace. Now, as more workers get sick — and sometimes die — from increasingly intense and frequent heat waves, labor laws are barely keeping up with the new hazards of climate change.

This summer it was so hot in southern Europe, where temperatures passed 115 degrees Fahrenheit, that local governments in many areas of Greece, Italy and Spain ordered outdoor work to stop in the afternoons for several weeks.

Japan, reeling from one of its worst heat waves on record, required employers to protect workers from heat stroke risks or face $3,400 fines.

In Singapore, employers must install sensors to measure heat and humidity levels every hour at large outdoor work sites, and provide relief accordingly.

In the United States, even as a national heat standard is yet to be finalized, local governments are enacting local measures. Boston passed a law this summer that required all city projects to have a “heat illness prevention plan” that trains work crews to spot heat illness and guarantee water and shade breaks.

Most of these measures are nascent and uneven. Critics say they are poorly enforced. They often collide with the needs of gig workers, who say they need to work no matter how hot it is.