SCHENECTADY — A Precision Industrial Maintenance worker died at Ellis Hospital late Wednesday night after being overwhelmed by toxic fumes in a truck at his Erie Boulevard workplace Tuesday, according to hospital spokeswoman Donna Evans.

Evans said that a second worker, also overcome by hydrogen sulfide fumes, was in good condition Thursday, an upgrade from his earlier critical condition.

Evans would not provide the names of the employees or additional information.

Schenectady County Medical Examiner Dr. N. Balasubramaniam said he conducted an autopsy on the man Thursday. He would not reveal his findings, citing privacy concerns.

Schenectady firefighters pulled the two men unconscious from the back of a tank truck Tuesday morning at Precision’s headquarters at 1710 Erie Blvd. Both men were taken in critical condition to Ellis Hospital and admitted to the intensive care unit.

Deputy Fire Chief Mark Fragomeni said one man apparently went inside the tanker, used to haul raw sewage, and was overcome by the fumes. The second man went to assist and also was overcome.

The tanker was empty, having dropped off its load earlier at the city’s waste treatment plant.

Hydrogen sulfide is a gas byproduct of sewage. Precision handles industrial wastes.

The Albany office of the federal Occupational Safety and Health Administration is investigating the incident.