WEST BATH – Four homemade bombs have been placed in mailboxes in the area, but none has caused injuries, authorities said.

One of the devices found in the home mailbox of labor lawyer Patrick McTeague was detonated safely on Monday, and law enforcement officials were investigating the fourth incident on Tuesday.

The device consisted of a plastic soda bottle filled with materials designed to react and cause the bottle to expand.

The resulting explosion had the power of a quarter of a stick of dynamite, sad Steve Hinds, chief deputy of the Bath Fire Department, who lives near the McTeague residence in West Bath.

McTeague’s wife found the 3-liter soda bottle in her mailbox and placed it on the ground. Edna McTeague noticed that the bottle was deformed from the pressure inside and called authorities.

The device exploded with a sound like a gunshot when firefighters using protective gear detonated it Monday evening.

Edna McTeague, who was shaken by the incident, said she felt lucky that she was not harmed. What’s worse, she said, her grandchildren sometimes retrieve her mail and could have been hurt.

“Especially during this particular time in the world, it’s sad that someone would think this is a joke,” she said.