Cory Barr, a captain with the Sun Prairie Volunteer Fire Department and owner of a tavern destroyed in the blast, was killed in the explosion.

Two other volunteer firefighters were injured.

VC Tech, which was subcontracted by Bear Communications, punctured an unmarked underground gas line at about 6:20 p.m. on July 10 while boring a hole under Bristol Street and Main Street in Sun Prairie as part of a fiber communication line project for Verizon.

The damaged gas line led to the explosion about 45 minutes after it was punctured, destroying five buildings, damaging several others and displacing dozens of residents.

An OSHA investigator met with company representatives the day after the explosion, according to the federal body that oversees workplace safety.

Each company has 15 business days to pay the fine, request a conference with OSHA or contest the findings, according to OSHA’s citations.

Gas line was unmarked

It’s unclear what ignited the explosion, according to records of the investigation released last month.

VC Tech had been subcontracted by Bear Communications, which had been contracted by Verizon for the fiber-optic cable project.