A Rhode Island medical manufacturing facility was evacuated Thursday afternoon after about 30 workers were exposed to a chemical release.

A HazMat response was staged outside ZOLL Medical Corp/Bio-Detek in Pawtucket around 5 p.m., and a “mass casualty incident” was declared, according to Patch. That language is used by emergency responders who are overwhelmed on a call, and does not necessarily indicate casualties.

Employees outside the facility said they were told to leave the building after several of their co-workers began to feel sick amid reports of an unidentified chemical release, according to WPRI 12 News.

The Pawtucket Fire Department believed a chemical spill was to blame for workers who complained of trouble breathing, and irritation in their eyes, nose, mouth and throat.

Employees of the facility, which was fined in 2018 for violating environmental controls, were instructed not to speak to reporters, the local station said.

“No major injuries were reported, though several individuals were transported to area hospitals for further evaluation,” Chief Goncalves, Acting Public Safety Director in Pawtucket said.

The state’s Department of Environmental Management’s emergency response team is investigating.