A paramedic consoles a man after three people died at a mushroom farm in Langley, B.C., on Friday. (Darryl Dyck/CanadianPress)

At least three workers are dead after noxious fumes were released in a utility shed at a mushroom farm in Langley, B.C., the RCMP confirmed Friday night.

At least two other workers were reported in critical condition, and a third was in serious condition, the Mounties said.

Hazardous materials crews converged at about 5 p.m. on Farmers Fresh Mushrooms, located at 237th Street and 16th Avenue in the Vancouver suburb.

Three air ambulances and dozens of firefighters from three different halls were called to the farm after several people working on the site "either accidentally or intentionally released" a toxic chemical, said Langley RCMP Const. Holly Marks.

Details were sketchy, but according to an employee, the three men were in a utility shed containing chemicals used in composting when they were overcome by the noxious fumes.

Other workers went in to try to help them and were overcome by the fumes themselves, Marks said, adding that the men who were in the shed when the gases were released died at the scene.

Jim Sinclair, president of the British Columbia Federation of Labour, said there have been too many tragedies involving farm workers in this province, and called for a public inquiry.

"A year and a half ago we had three women die in a van accident that was completely avoidable," Sinclair said. "Now we have three more deaths. In order to get these deaths under control and to stop them, we need a public inquiry. Let's look at the agriculture industry."

WorksafeBC, formerly the provincial Workers' Compensation Board, and the B.C. Coroners Service are investigating.

With files from the Canadian Press