Congressional Democrats are asking the Biden administration to introduce federal protections for workers exposed to extreme heat.

Federal work safety standards are set by the Occupational Safety and Health Administration, or OSHA. Under OSHA’s rules, workplaces must be free from recognized hazards that pose a risk of serious harm or death to employees.

But enforceable regulations on heat exposure still differ from state to state. In a letter sent this week, lawmakers including Arizona’s Raúl Grijalva and Ruben Gallego say OSHA should introduce federal protections.

The lawmakers say Bureau of Labor statistics show heat illness causes an average of 700 deaths a year. They say amid record heat conditions now, OSHA should require employers to provide adequate hydration, rest breaks with shaded areas or AC, and medical services to respond to heat-related illnesses. They also say industries should make adaption plans for a future of high-heat working conditions.