Hexachlorocyclopentadiene (HCCPD)
HCCPD·Affects kidneys, lungs
A chemical intermediate used to make organochlorine pesticides and flame retardants. Found in groundwater near former pesticide manufacturers and chemical waste sites.
HCCPD
EPA limit
0.05 mg/L (MCL)
Most at risk
Households near former pesticide manufacturing plants, flame retardant producers, or chemical waste sites
Found in
Well water · Industrial areas
AquaOx filters
YesActivated coconut shell carbon
What it does to you
Health effects
HCCPD primarily affects the kidneys and the lungs (when inhaled as vapor). Animal studies show kidney tubule damage and respiratory irritation. The compound has a pungent, acrid odor that humans can detect at extremely low concentrations, sometimes below toxicological thresholds.
The EPA has not classified HCCPD for carcinogenicity due to limited data, but the compound is acutely toxic by all routes of exposure. Like other chlorinated VOCs, it is volatile and contributes to inhalation exposure during showering and dishwashing.
The MCL of 50 ppb is set with a safety factor below the lowest observed effect level in animal kidney studies.
Where it comes from
How it gets into your water
HCCPD is rarely a finished commercial product. It is a chemical intermediate used to manufacture organochlorine pesticides such as chlordane, heptachlor, endrin, dieldrin, and aldrin (all now banned), and to produce chlorinated flame retardants.
Groundwater contamination comes almost exclusively from former pesticide manufacturing plants and chemical waste disposal sites. The most famous case was the 1977 spill in Louisville, Kentucky, which contaminated the city's wastewater treatment system. Modern detections cluster near historic Superfund sites associated with pesticide production.
Pesticide manufacturing
Intermediate for chlordane, heptachlor, and other banned pesticides
Flame retardant plants
Production of chlorinated flame retardants
Contaminated wells
Plumes near former manufacturing sites
Chemical waste sites
Historic disposal of process residues
Find out for yourself
Is it in your water?
HCCPD is EPA-regulated, so utilities must test for it and report results on the Consumer Confidence Report. Detections in finished city water are uncommon outside of areas with a history of pesticide manufacturing.
Private well owners near former pesticide plants or chemical waste sites should request a full VOC panel that specifically includes HCCPD. The compound has a strong odor that can sometimes alert residents before laboratory confirmation, but odor is not a reliable indicator of safe versus unsafe concentrations.
The fix
How AquaOx filters it
Activated carbon is the standard treatment for chlorinated VOCs including HCCPD. The Centaur catalytic carbon and coconut shell carbon stages in The AquaOx adsorb the compound efficiently as water passes through.
For homes near former pesticide manufacturing sites or known contamination plumes, we recommend pairing The AquaOx whole-home system with the under-sink RO at the kitchen tap to add a second-stage polish on drinking and cooking water.