Read our Privacy noticeHours before a deadly explosion ripped through a Pennsylvania nursing home last month, staff grew concerned about the smell of natural gas on several floors and brought in workers from the local utility company to check it out, federal regulators said Wednesday. Two residents and an employee were killed and about 20 people injured, including one of the utility workers, just a few days before Christmas. Part of the building collapsed, trapping people inside, as emergency workers, staff and even medics from a nearby hospital rushed to evacuate people. Exelon, PECO’s parent company, shut off the gas flow to the facility almost two hours after the explosion, according to the report. According to the report, a maintenance director at Bristol Health & Rehab Center reported the smell of natural gas in the basement on Dec. 23 and called the utility company.