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FortisBC answers health concerns on Delta gas, odourant leak

Mercaptan is not routinely measured in outdoor air by regular monitoring networks
The Interconnect Station in Ladner is where FortisBC receives gas from a third-party producer. In this case, receiving renewable natural gas produced from landfill gas at the Village Farms greenhouse site. FortisBC image

Fraser Health did not find evidence of significant health impacts in the short-term following FortisBC’s inadvertent release of natural gas and odourant that overwhelmed parts of South Delta, and they do not expect there to be a substantial risk of longer-term health impacts.

That’s according to a response from the health region from an inquiry from Mayor George Harvie regarding potential health effects of the odour event that occurred on Jan. 16, when a quantity of natural gas with a high concentration of the mercaptan was released at the FortisBC Interconnect Station near Ladner Trunk Road and 80 Street.

Mercaptansare sulfur-containing compounds primarily used as odorants in natural gas.

The odour moved through the community causing public concern and a high volume of calls to Delta’s fire and emergency services. Two months later, a delegation from FortisBC made a presentation to council assuring it will improve communications.

Harvie then wrote to Dr. Victoria Lee, President and CEO of Fraser Health, requesting an assessment of potential health effects that the community could face.

According to the health region, there are no air quality guidelines for mercaptan and it is not routinely measured in outdoor air by regular monitoring networks.

While limited evidence is available on low-level exposure to the general public in such incidents, the available evidence suggests that mercaptans commonly used as odourants have relatively low toxicity.

People can detect the smell of mercaptans at a much lower level than the level that can cause short-term health effects, while exposure to strong odours sometimes results in short-lived symptoms such as irritation of the nose and throat, and headaches.

The health region added that it did not find an increase in visits to the emergency department at Delta Hospital when the gas was released and the following days for symptoms related to the strong odour exposure.

“We have reached out to FortisBC to gather additional details of the incident including the specific composition of their mercaptan odourant and the estimated volume that was released. This additional information will best inform assessment of potential exposure at the incident site; however, exposure of the general public at different locations in the City of Delta will remain challenging to assess,” the letter adds.