1,2,4-Trichlorobenzene
1,2,4-TCB·Affects liver, kidneys
An industrial solvent and dye carrier with limited modern use. Found in groundwater near chemical plants, textile mills, and former waste disposal sites.
1,2,4-TCB
EPA limit
0.07 mg/L (MCL)
Most at risk
Households near chemical plants, textile mills, or former industrial disposal sites
Found in
City water · Well water · Industrial areas
AquaOx filters
YesActivated coconut shell carbon
What it does to you
Health effects
1,2,4-TCB affects the liver and the kidneys. Animal studies show liver enlargement and porphyria-related effects, along with adrenal gland changes at chronic doses. The EPA has not classified the compound for carcinogenicity because of limited data.
The compound is moderately volatile, so it can off-gas from water during hot showers and contribute to inhalation exposure. It is lipophilic and bioaccumulates in fatty tissue with chronic intake.
The MCL of 70 ppb is set with a safety factor below the lowest observed adverse effect level in animal liver and kidney studies.
Where it comes from
How it gets into your water
1,2,4-TCB was used historically as a dye carrier in textile manufacturing, a solvent for waxes and resins, and a chemical intermediate. Use has declined as safer alternatives became available, but legacy contamination remains.
Groundwater detections cluster near former textile mills, chemical plants, and pesticide formulators. The compound is denser than water and persists in subsurface plumes for decades. Improper waste disposal at industrial sites accounts for most current contamination.
Chemical plants
Solvent and intermediate manufacturing
Textile mills
Legacy dye-carrier contamination
Contaminated wells
Plumes near industrial disposal sites
Pesticide formulators
Carrier in older formulations
Find out for yourself
Is it in your water?
1,2,4-TCB is on the EPA's regulated contaminant list, so utilities test for it and report results on the Consumer Confidence Report. Detections in treated city water are uncommon.
Private well owners near chemical manufacturing areas, former textile mills, or known Superfund sites should request a VOC panel that specifically includes 1,2,4-TCB and the dichlorobenzene family. State drinking-water programs maintain maps of known contamination sites.
The fix
How AquaOx filters it
Activated carbon is the standard treatment for chlorinated aromatic solvents. The Centaur catalytic carbon and coconut shell carbon stages in The AquaOx adsorb 1,2,4-TCB efficiently 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 to add a second-stage polish on drinking and cooking water.