Subcontractor Heartland Midwest didn't immediately respond to Monday's report from city officials.
A Missouri Gas Energy official has said that Heartland Midwest reported hitting a natural gas line with an underground borer more than an hour before Tuesday night's explosion. The blast and ensuing fire leveled JJ's restaurant near a busy outdoor shopping area called the Country Club Plaza. One person was killed and 15 others were injured.
Four of the injured remained hospitalized Monday at the University of Kansas Hospital, including one person who was in critical condition.
Heartland Midwest said last week that it's cooperating with authorities.