Federal officials are reinstating hundreds of U.S. health workers who were laid off last year from a small health agency that aims to protect workers.

In April, President Donald Trump’s administration gutted the National Institute for Occupational Safety and Health, where scientists, engineers and others conduct research and recommend ways to prevent work-related injury, illness, disability and death.

Government officials laid off close to 900 of NIOSH’s 1,000 employees. The layoffs were part of the Republican president’s remaking of the federal workforce led by then-adviser Elon Musk and the Department of Government Efficiency, but they drew harsh rebukes from firefighters, coal miners, medical equipment manufacturers and a range of others.

Some employees were brought back last year amid legal challenges and political pressure, including those who staffed a health monitoring program for miners in West Virginia. But now all the terminations have been rescinded, according to the American Federation of Government Employees, which represents workers at NIOSH and parts of the U.S. Centers for Disease Control and Prevention.