Chlorine Leak Requires Special Operations Team Response

On Friday evening at approximately 8:30PM, Westchester County’s all-volunteer Hazardous Materials Response Team responded to a chlorine leak at what’s known as the “Shaft 18” water treatment plant near the Kensico Dam in Valhalla. Once notified, the Team responded as a mutual aid response with the Valhalla Fire Department and an agreement with the Department of Environmental Protection (DEP). The leak, apparently cause by either a failed pipe or fitting, was back in service about 24 hours after the initial chlorine leak forced its shutdown.

A master stream from a Valhalla FD engine is applied to a
door of the facility. Security issues prohibit more
detailed photos.

While the cause of the leak remains unknown, officials have narrowed the failure to one section of a pipe in “Shaft 18”. Entry was attempted by the Hazardous Materials Response Team and DEP personnel in level B response suits to get readings and evaluate the damage. As the responders got close to the building, their readings were found to be at such a high concentration, the entry team was forced to withdraw and change into level A response suits. This change of suits would allow them entry into the hazardous atmosphere to do their assessment. While the readings were extremely high, the chlorine spill was contained inside the building and the public was never at risk to exposure.

According to DEP representatives, chlorination operations were resumed to normal operations shortly before 5 p.m. on Saturday. Crews spent much of Saturday replacing equipment, as well as alarm sensors, which became damaged because of the leak. After testing all of the plant’s systems, and everything was certified, the systems were put back on line. 

ABG asked if this plant was even necessary after the new RV Water Treatment Plant on Walker Road was put on line. The explanation was that most of the water is treated at the new plant but still requires final treatment with chlorine beyond just the UV treatment. As such, the Shaft 18 facility is still required for water treatment but used in a more reduced capacity than before. The plants process drinking water for a variety of communities in Westchester, as well as for most of New York City’s clean water supply. But officials said that the leak did not affect water service, and that there was never a threat to public safety.

Other water treatment plants in the Westchester water purification system increased their chlorination operations of water during the Valhalla facility’s shutdown. Water going to New York City was chlorinated at a separate, alternate site farther down the water-line system. Residents may have smelled a slight bleach-like odor on Saturday as the facility was being aired out.

The Valhalla FD and the County’s Special Operation’s Response Teams encompasses Hazardous Materials and Technical Rescue response professionals from many walks of life. Their dedication, training, and responses help to keep everyone’s taxes low and safety at an all-time high level.