GATESVILLE, Texas (CBSDFW.COM/AP) — A worker severely burned in a 2018 deadly natural gas explosion at a hospital in Central Texas has sued a Dallas-based utility seeking more than $1 million.

Matt Aaron of Oglesby alleges Atmos Energy Corporation failed to maintain its natural gas system and include a “rotten egg” odor to alert of possible leaks.

Three people were killed and 13 hurt in the June 26 accident during construction at Coryell Memorial Hospital in Gatesville, about 40 miles west of Waco. All of the dead and injured were construction workers. There were no doctors or patients injured in the explosion.

hospital explosion in Gatesville (credit: Cody Self)

Investigators in November concluded natural gas flowed from disconnected lines into a boiler room. Wednesday’s lawsuit says Aaron, employed by Lochridge Priest Inc., was nearby. Officials aren’t sure what ignited the gas.

Atmos on Thursday repeated earlier findings that no leaks were found in its natural gas system and odorant levels complied with regulations.

(© Copyright 2019 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)