While there have been some industrial uses for TCP as a cleaning and degreasing solvent, it is our experience that the majority of TCP groundwater contamination is a result of the use of certain soil fumigants which incorporate TCP into their composition.
Dow Chemical Company and Shell Oil Company manufactured and sold TCP-containing soil fumigants for decades. Dow sold its fumigants under the brand names of Telone (and after the mid-1970s Telone II). Shell’s fumigant was sold under the brand name of D-D. These fumigants were used extensively by farmers for the control of nematodes, microscopic worms that feed on plants, and were applied using high application rates. TCP was an inactive, and thus unnecessary ingredient, in Telone and D-D. TCP is highly mobile, persistent in the environment (meaning it does not break down), and is heavier than water. Such characteristics explain its propensity to contaminate groundwater.
TCP has been found to be highly toxic in drinking water. Through animal studies, researchers have concluded that TCP is a potent carcinogen. The International Agency for Research on Cancer classifies TCP as “probably carcinogenic to humans”. The National Toxicology Program classifies TCP as “reasonably anticipated to be a human carcinogen.” Concern over TCP’s toxicity led the State of California to adopt a Public Health Goal (PHG) for TCP of 0.7 parts per trillion (5 ppt), one of the lowest PHGs ever set. And in 2017 California adopted a Maximum Contaminant Level (MCL) of 5 ppt for TCP. An MCL is a health protective drinking water standard that must be met by public water systems.
The ELG has recovered hundreds of millions of dollars on behalf of water providers in litigation against Dow and Shell for TCP contamination. Most recently, our attorneys recovered the largest settlement to date in TCP litigation on behalf of the City of Bakersfield and the California Water Service Company. Such recoveries have granted water providers with the funds necessary to install the expensive treatment necessary to remove TCP from their drinking water and avoid passing such costs to their ratepayers.