What is Toxaphene and Why Does It Matter?

Toxaphene is a pesticide that was widely used in the United States from the 1940s through the 1980s, primarily on cotton crops in the South. It's a mixture of chemicals made by combining chlorine with camphene, a compound derived from pine trees. The EPA banned toxaphene for most uses in 1982 and completely in 1990, but that doesn't mean it's gone. This chemical clings to soil and sediment for decades. Rainwater and runoff carry it into rivers, lakes, and groundwater — the same sources that feed public water systems. Old agricultural land is especially likely to still harbor toxaphene residues, even 40 years after the last application.

The health risks from toxaphene are serious enough that the EPA classifies it as a probable human carcinogen (cancer-causing substance). Animal studies show that long-term exposure damages the liver, kidneys, and nervous system (EPA). At high enough levels, it can also disrupt the endocrine system — meaning it interferes with hormones that regulate growth, reproduction, and metabolism (National Toxicology Program). Children are particularly vulnerable because their developing bodies are more sensitive to hormone-disrupting chemicals. Even low-level exposure over time carries risk, which is why health advocates argue the current legal limit isn't protective enough.

The EPA's current maximum contaminant level (MCL) for toxaphene in drinking water is 3 parts per billion (ppb). The Environmental Working Group (EWG) sets a much stricter health guideline of just 0.00073 ppb — nearly 4,000 times lower than the federal limit. That gap exists because the EPA's limit is based on older science and balances technical feasibility with health protection. The EWG guideline is based purely on cancer risk, aiming to keep that risk below 1 in 1 million. Of the 17 water systems where toxaphene has been detected, 13 had levels above the EWG health guideline. The average detected level was 0.302 ppb, and the highest recorded level reached 0.893 ppb. That's still below the EPA's legal limit — but it's more than 1,200 times above what the EWG considers safe.

Geographically, Florida accounts for 10 of the 17 affected systems — by far the highest concentration. That's not surprising. Florida has a long history of heavy pesticide use on cotton, citrus, and vegetable crops. The state's sandy, porous soil allows chemicals to migrate into groundwater relatively quickly. South Carolina and Georgia also appear on the list, both states with significant historical cotton farming. New York and New Hampshire each have one affected system, which may reflect legacy contamination from older agricultural or industrial sites rather than active farming. The pattern strongly suggests that toxaphene contamination is tied to past agricultural use, not current activity. That also means it can be difficult to predict where it will show up next, since contamination depends on decades-old land use history.

The good news is that toxaphene can be effectively removed from drinking water. Granular activated carbon (GAC) filtration is one of the most reliable methods — it works by attracting and trapping organic chemicals like toxaphene as water passes through. Reverse osmosis (RO) systems are even more effective, removing up to 99% of a wide range of contaminants including pesticides and their breakdown products. If you live in Florida or another state on this list, a whole-home or under-sink RO system is worth considering. Echo Water's reverse osmosis systems are designed specifically to address the kinds of legacy chemical contamination that standard filters miss. The first step is always knowing what's in your water — check your annual Consumer Confidence Report (CCR), which your water utility is required to provide. If toxaphene shows up, don't wait. Filtration is one of the most direct actions you can take to protect your family from a chemical the government stopped allowing decades ago, but hasn't fully cleaned up yet.

Regulatory Standards for Toxaphene

Cities With the Highest Toxaphene Levels

States Most Affected by Toxaphene

Frequently Asked Questions

Related Contaminant Guides