PITTSBURGH — The parents of a contractor killed when a southwestern Pennsylvania natural gas well exploded in February have sued the Chevron subsidiary that owns the well.

The lawsuit filed by the parents of Ian Robert McKee, 27, contends Chevron Appalachia was negligent but doesn’t specify how or why. Instead, the lawsuit said only that the “explosion is the sort of event which normally would not occur in the absence of negligence.”

John Gismondi, the Pittsburgh attorney for Denise and Robert McKee, said in a statement the lawsuit was filed so the plaintiffs can demand information and answers from the company.

“If we do not have a lawsuit on record, we have no ability to demand information from Chevron that helps us sort out the details of what happened here, and the sooner we get that information, the further along we will be in protecting the family’s interest,” Gismondi said Wednesday.

“The investigation is still ongoing, so there is much to learn about the cause of the accident, but right now we know that Chevron was in charge of the well, and something obviously went wrong.”