Government staffing cuts have gutted a small U.S. health agency that aims to protect workers — drawing rebukes from firefighters, coal miners, medical equipment manufacturers and a range of others.

The National Institute for Occupational Safety and Health, a Cincinnati-based agency that is part of the Centers for Disease Control and Prevention, is losing about 850 of its approximately 1,000 employees, according to estimates from a union and affected employees. Among those ousted were its director, Dr. John Howard, who had been in the job through three previous presidential administrations.

The layoffs are stalling — and perhaps ending — many programs, including a firefighter cancer registry and a lab that is key to certifying respirators for many industries.

The cuts are “a very pointed attack on workers in this country,” said Micah Niemeier-Walsh, vice president of the union local representing NIOSH employees in Cincinnati.

Unions that represent miners, nurses, flight attendants and other professions have criticized the cuts, saying it will slow the identification and prevention of workplace dangers. Rallies in Cincinnati and other cities drew not only fired CDC employees but also members of unions representing teachers, postal workers and bricklayers, Niemeier-Walsh said.

NIOSH doctors review and certify that 9/11 first responders who developed chronic illnesses could qualify for care under the federal government’s World Trade Center Health Program, noted Andrew Ansbro, president of a union that represents New York City firefighters.

“Dismantling NIOSH dishonors the memory of our fallen brothers and sisters and abandons those still battling 9/11-related illnesses,” Ansbro said in a statement. NIOSH was created under a 1970 law signed by President Richard Nixon. It started operations the following year and grew to have offices and labs in eight cities, including Cincinnati; Pittsburgh; Spokane, Washington; and Morgantown, West Virginia.

In the more than 50 years since, it has done pioneering research on indoor air quality in office buildings, workplace violence and occupational exposures to bloodborne infections.

NIOSH investigators identified a new lung disease in workers at factories that made microwave popcorn, and helped assess what went wrong during the Deepwater Horizon oil rig disaster. It was recently involved in the CDC’s response to measles, advising on measures to stop spread within hospitals.

Some of its best-known work is related to mining. It trains and certifies doctors in how to test for black lung disease, and the agency conducts its own mobile screenings of miners. For years, NIOSH owned an experimental mine in Pennsylvania and two years ago announced it was developing a replacement research facility near Mace, West Virginia, that would feature tunnels and other mine structures.

Studies have concluded NIOSH research helps the nation save millions of dollars each year in avoided workers’ compensation and other costs.