NORWELL (CBS) – Several smoke bombs went off inside a local post office on Friday.

The State Fire Marshal’s office says an out-of-state company had sent 30 smoke bombs of various sizes through the mail to a family in Norwell.

It’s unclear what caused them to ignite inside the facility.

Postal workers saw the smoking box and rushed it outside. The State Police bomb squad was called in.

It is illegal to send smoke bombs through the mail. Possession of smoke bombs in Massachusetts is also illegal.

State and federal officials are investigating the incident.