Two people are dead and two others are wounded following a gas line explosion near Farmersville, Texas, on Monday.

At around 3:30 p.m., authorities responded to the blast after employees from Bobcat Contracting and Fesco Petroleum Engineering, subcontractors for Atmos Energy, conducted pipeline maintenance, the Collin County Sheriff’s Office wrote. After initial investigations, the incident appeared to be an “accident,” though the FBI has been called to follow-up.