1,1,1-Trichloroethane
1,1,1-TCA·Affects brain, liver
An industrial degreasing solvent phased out under the Montreal Protocol for depleting the ozone layer. Still found in groundwater near former industrial sites and old waste disposal areas.
1,1,1-TCA
EPA limit
0.2 mg/L (MCL)
Most at risk
Households near old industrial sites, machine shops, or former hazardous waste areas
Found in
City water · Well water · Industrial areas
AquaOx filters
YesActivated coconut shell carbon
What it does to you
Health effects
1,1,1-TCA primarily affects the central nervous system and the liver. Acute high-dose exposure causes dizziness, loss of coordination, and at very high levels cardiac arrhythmias. Chronic low-dose exposure has been linked to mild liver effects in animal studies.
Unlike most of its chlorinated cousins, 1,1,1-TCA is not classified as a probable human carcinogen by the EPA. Its toxicity profile is considered lower than TCE or PCE, which is why the MCL is set relatively high at 200 ppb.
The compound is volatile, meaning it can off-gas from water during showers and dishwashing, contributing to inhalation exposure on top of ingestion.
Where it comes from
How it gets into your water
1,1,1-TCA was one of the most widely used industrial solvents in the 20th century, primarily for cold metal degreasing, electronics cleaning, and as a propellant. Production was phased out in the United States by 1996 under the Montreal Protocol because of its ozone-depleting potential.
Despite the phase-out, decades of industrial use left a legacy of soil and groundwater contamination. The compound migrates slowly through soil and persists in aquifers for years. Most modern detections trace back to leaking underground storage tanks, old machine shops, electronics manufacturers, and improperly closed industrial waste sites.
Metal degreasing
Legacy contamination at old machine shops and factories
Electronics plants
Cleaning solvent for circuit boards before phase-out
Contaminated wells
Plumes from former industrial waste sites
Underground tanks
Leaks from old solvent storage
Find out for yourself
Is it in your water?
1,1,1-TCA is an EPA-regulated contaminant, so all community water systems test for it and report results in their annual Consumer Confidence Report. Detections in treated city water are rare.
Private well owners in industrial corridors, near old manufacturing sites, or within range of former Superfund areas should request a VOC panel that includes 1,1,1-TCA, TCE, and PCE. State drinking-water programs and EPA EnviroFacts both maintain public maps of known contamination sites.
The fix
How AquaOx filters it
Activated carbon is the standard treatment for chlorinated solvents including 1,1,1-TCA. The Centaur catalytic carbon and coconut shell carbon stages in The AquaOx adsorb the compound as water passes through.
For homes on a known industrial plume, we recommend pairing The AquaOx whole-home system with the under-sink RO at the kitchen tap for a second-stage polish on drinking and cooking water.