Authorities say a custodian has died at a Massachusetts elementary school and several public safety employees who responded to the scene developed symptoms of possible chemical exposure.

The district attorney's office says the man found dead Monday morning at the school in Plymouth was 53-year-old Chester Flattery.

First responders had been called out to investigate the report of an unresponsive man. Three firefighters, three police officers, two state troopers, two paramedics and a school employee were taken to hospital for evaluation.

Manomet Elementary School was evacuated and authorities say the building remained closed as a hazardous materials response team tried to identify the chemical agent.

An autopsy was planned for Flattery by the office of the chief medical examiner.