A November 2011 incident in which two Massachusetts workers were seriously burned by an arc flash has resulted in citations and $11,000 in fines against the employer.

OSHA found that Interstate Electrical Services, a North Billerica electrical contractor, failed to ensure that an energized electrical panel was effectively guarded. The workers were installing electrical service when a piece of equipment made contact with an energized part of an electrical panel, resulting in the arc flash.

OSHA issued a willful citation -- with a $70,000 fine. The company also received two serious citations -- with $11,000 in fines -- for additional electrical hazards posed by a damaged power cord and an energized electrical wire that was not protected against damage.

Interstate Electrical Services has 15 business days from receipt of its citations and proposed penalties to comply, meet with OSHA or contest the findings before the independent Occupational Safety and Health Review Commission.