A small public water system in Gridley at the Manzanita Elementary School recently tested positive for elevated levels of the chemical 1, 2, 3 – Trichloropropane (TCP). TCP is a man-made chemical historically used in agricultural regions as a pesticide and herbicide additive and is a known carcinogen under Prop 65, California’s Safe Drinking Water and Toxic Enforcement Act.

Manzanita Elementary School has been immediately provided access to safe drinking water and are protected from further exposure.

The school is working with Butte County Environmental Health and the State Water Resource Control Board on a planning study to determine the best course of action which may be to install a new deep well or to install a treatment system that will remove the chemical from the drinking water. Water treatment for TCP is typically achieved through a filtration system using granular activated carbon, which absorbs the chemical, filtering it out of the water.

California is the first state to begin testing for TCP and is in the process of developing treatment technology. In December of 2017 the maximum contamination level (MCL) for TCP was adopted and new sampling requirements went into effect. Prior to this, TCP has been an unregulated chemical. The first sampling of these water systems began in February and March of 2018.

Learn more about TCP on the State Water Board website.

Although TCP was banned from use in the 1990s, the chemical does not break down easily in the environment and much of it has leached into the groundwater over decades and contaminated drinking water wells. Some people who drink water containing elevated levels of TCP, over many years, may have an increased risk of getting cancer.