HOUSTON (AP) — Three contractors who worked at a Houston-area chemical plant say in a lawsuit that the company knew that a flammable gas was leaking before a deadly fire erupted but did not order an evacuation.

The Houston Chronicle reports the lawsuit was filed Monday by the contractors, who were injured when the fire began April 2 at the plant operated by KMCO LLC in Crosby.

They contend that KMCO officials were aware of a leaking valve on a high-pressure line that allowed the gas to escape and set off the fire at the chemical storage facility. One worker was killed and several others were hurt.

Monday's lawsuit is at least the third filed against KMCO.

KMCO President and CEO John Foley said in a statement that the fire remains under investigation and any legal complaints at this point should be considered "unverified."