State utility regulators on Thursday imposed a $1.1 million fine on UGI Utilities Inc. for alleged violations relating to a 2017 gas explosion in Lancaster County that killed a utility worker and damaged four houses.

The Pennsylvania Public Utility Commission unanimously approved the settlement with the company, a subsidiary of UGI Corp. of Valley Forge. The agreement also requires the company to enhance gas safety measures and to open a new emergency response training center.

The PUC in 2018 filed a formal complaint against UGI, saying it had failed to properly react to a hazardous condition when its workers responded to a reported gas leak at a house in Millersville on July 2, 2017.

The complaint alleged that UGI failed to follow its own written procedures at the time of the explosion, and that its procedures were deficient.

The explosion occurred while workers were digging up a gas leak, but UGI had not completely disconnected service to the area. The blast killed Richard A. Bouder, 54, injured three other utility workers, and damaged four houses on a cul-de-sac, two of which were later condemned.

The complaint initially sought $2.1 million in fines. The PUC said that as a result of the settlement, UGI will spend more than $50 million on safety enhancements, infrastructure replacement, and additional training focused on accident prevention.

UGI Utilities, based in Denver, Pa., is one of the state’s largest gas utilities and serves about 650,000 customers in 45 counties.