Crystallization of chemical solution prompted evacuation at Dartmouth facility last week

Police block the entrance to the Bedford Institute of Oceanography during an evacuation on Jan. 22, 2025. (CTV/Paul DeWitt)

The Bedford Institute of Oceanography in Dartmouth and the MacKay Bridge temporarily closed last week after a liquid solution containing picric acid that had crystallized was found.

The Halifax Regional Municipality issued an emergency alert about a chemical spill at the research facility around 4:20 p.m. on Wednesday. A mandatory 250-metre evacuation was put in place and the MacKay Bridge, which is the near the building, was closed to traffic.

The chemical – which was initially believed to be formaldehyde but was in fact dry picric acid – was removed and the bridge was reopened around 6 p.m.

Kate Trask, communications advisor with Fisheries and Oceans Canada, said a typically safe liquid solution containing 75 per cent picric acid crystallized at the Katherine Ellis Building at the Institute on Wednesday afternoon.

“In this state, the normally safe chemical solution becomes unsafe,” Trask said in an email. “In accordance with established procedures, the employee quickly reported this matter, and Halifax Fire and Emergency services were called to the building. At the recommendation of Halifax Fire and Emergency services we evacuated the full campus.

“No employees were injured.”

Trask said scientists sometimes use picric acid as a fixative for biological samples. Fixatives can be used to preserve such samples.

According to the Government of Canada, picric acid, which was discovered in 1771 by British chemist Peter Woulfe, is classified as a flammable solid when wetted with more than 30 per cent water and becomes an explosive with less than 30 per cent water.

Picric acid was used in bombs and grenades during the First World War. Most famously, an ammunition ship carrying picric acid and TNT exploded in the Halifax Harbour in 1917.

It is used for dyes and as a chemical reagent in labs.

Laura Wright with the Halifax Regional Municipality said emergency crews removed the picric acid from the Institute in an explosive disposal container on Wednesday. They then took it to an “outdoor location” and destroyed it in a controlled countercharged explosion.

“Through this process, there are no impacts to the environment,” Wright said in an email.

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