Nine workers at a Surrey, B.C. waste transfer station were isolated and decontaminated this morning after sudden exposure to an unknown gas.

After moving a certain pile of trash just before 8:30 a.m., the workers complained of difficulty breathing and irritation in the throat and nasal passages.

A supervisor from a separate building, who went to check out the situation, immediately experienced the same health problems.

Battalion Chief Lorne West, with the Surrey Fire Department, says crews and emergency services arrived and scrubbed the workers down.

He says after 30 to 40 minutes of breathing fresh outdoor air, the workers felt their symptoms dissipate and didn't require hospitalization.

The Wastech plant was closed for the rest of the day while specialists analyze and try to identify the hazardous substance.