Envelope containing suspicious powder bursts open at Montana Department of Labor office

Envelope with powder sent to Montana state office

HELENA, Mont. — An envelope containing a suspicious powder burst open Tuesday while being handled by state workers in a Montana government office.

Three Department of Labor workers and a Helena city police officer were isolated while a state lab tested the substance. Other workers on the third floor of the Walt Sullivan building were relocated elsewhere for the day.

The state says the envelope burst, as if there were a triggering device to distribute the powder. The contents of the envelope were otherwise described as a standard Department of Labor form.

A state spokeswoman says there was no indication who sent the letter to the state.