Nitric Acid Reaction Caused Peterborough Explosion

Monday's explosion at New Hampshire Ball Bearings in Peterborough was caused by a nitic acid reaction, according to fire officials.

New Hampshire State Fire Marshal J.William Degnan and Peterborough Fire Chief Joseph P. Lenox III announced in a press release Wednesday afternoon that the investigation into the explosion is ongoing. As a result of the on scene investigation and examination, they said the incident continues to be classified as an industrial accident. The cause of the explosion has been determined to be directly related to a nitric acid reaction. Nitric acid is an oxidizing agent commonly used in industrial processes.

Late Tuesday night, the on scene portion of the investigation was completed and the facility was turned over to New Hampshire Ball Bearings management so they could begin remediation and clean-up.  Clean Harbors Environmental Services will be assisting the company with this effort.

The investigative team, made up of members from the state Fire Marshal’s Office, OSHA, and personnel from the New Hampshire Department of Environmental Services will continue to conduct interviews and analyze documents, samples, and other evidence collected at the scene over the next several weeks. A final report regarding the exact origin and cause and any recommendations as a result of the investigation is also several weeks away.

Firefighters from 10 towns – including Milford – responded to the Peterborough manufacturing company on Monday afternoon following reports of a fire and explosion. More than a dozen people were injured, two of them critically.