Ammonia Persulfate Incident In Wellesley

The Wellesley Fire Department received a call for a chemical reaction between ammonia persulfate and an unidentified chemical in the area of Brookside Road and Oakland Street this morning at approximately 7 :18 a.m.

The incident was reported as a Tier-1 Haz Mat incident, and upgraded to a Tier 2 by 9 a.m. The upgrade was done to ensure there were enough personnel on site, said Police Lt. Marie Cleary.

Deputy Fire Chief Jeffrey Peterson said American Water Main, sub-contracted by the town to re-line sewer pipes in the area, accidentally mixed Ammonia Persulfate and another chemical, causing a vapor cloud and partially melting a 50-gallon container where the chemicals combined. Peterson said the two chemicals are usually combined as they are sprayed during application to pipes, but somehow the combination happened inside the container instead.  There were no injuries, and the vapor cloud dissipated harmlessly into the air, Peterson said. However, he said, the combination of chemicals was also potentially explosive, so they required care to dispose of.

Among the personnel summoned with The Tier-2 classification was a bomb expert, who helped assess the situation, Peterson said.

Metro Fire Team C responded for the call at about 8:12 a.m. In all, Peterson said, about 25 fire personnel, including the hazardous materials crew, responded. Peterson said they kept the heavily-geared firefighters cool in the 90-degree heat with an air-conditioned ambulance on scene, and the fire department's rehab van, which is also air-conditioned.

Brookside Avenue was blocked From Wellesley Avenue to Oakland Street, and access to the 17th Hole at the Wellesley Country Club was also blocked, until about 1 p.m., when they determined the chemicals were no longer a danger and could be removed. 

Hazardous waste disposal company Clean Harbors of Norwell was also called in to help with the disposal, Peterson said.