A second federal agency is investigating a collapse that killed two York firefighters.
Ivan Flanscha, 50, of Red Lion, and Zachary Anthony, 29, of York, died in a partial building collapse in March.
The men were part of crews sent to the former Weaver Organ and Piano Company the day after it had caught fire.
Flanscha and Anthony were putting out hotspots on the fourth floor when it collapsed beneath them.
The National Institute for Occupational Safety and Health is interviewing firefighters, city officials and anyone else who may know why the firefighters were in the building the day after the massive fire and who told them to go there.
The Bureau of Alcohol, Tobacco, Firearms and Explosives is investigating the fire.
The investigations are expected to take several months.