Perth gas odorant leak tracked to centre

The mystery gas smell which worried hundreds of Perth residents was likely to have been a leak of gas odorant from the industrial centre in Kwinana, south of the city.

An investigation was launched by authorities on Thursday, after hundreds of complaints were made to ATCO Gas Australia, with some residents claiming the smell was so strong it woke them up.

ATCO ruled out a gas leak from any of their infrastructure, with the Department of Environment Regulation (DER) taking over the investigation.

In a statement, DER said it was continuing its inquiry into the cause of the smell, but confirmed they were focusing on premises in the Kwinana industrial area.

"It is likely the odour was the result of a leak of gas odorant which is generally injected into otherwise odourless gases so they can be detected by people," a statement said.

"These gas odorants can be detected in the air at extremely low levels - as little as one part per billion."

The DER said they believed the emissions had ceased, however, investigations were continuing.