Ammonia leak in Mission

Hazardous materials crews in BC's Fraser Valley faced a tense situation early Friday morning when a cloud of ammonia gas spewed from a food processing plant.

The incident began at around 3 a.m. at the B.C. Frozen Foods plant between Mission and Hatzic, about 70 kilometres east of Vancouver.

Crews arrived to find a large plume of ammonia gas shooting from a refrigeration unit on the roof of the building, located between the Lougheed Highway and the north bank of the Fraser River.

No one was hurt and no homes were affected, but police shut down a two-kilometre section of the highway until around 7:30 a.m., briefly closed a nearby rail line, and kept boats off a stretch of the Fraser River until the leak was plugged.

The cause is still under investigation, but one fire official says a pressure relief valve in the refrigeration unit may be to blame.

Ammonia gas is a vital component in refrigeration or ice-making. The Canadian Centre for Health and Safety says inhalation severely irritates the nose and throat, and can cause lasting damage or death after even short-term exposure.