Benzene
C₆H₆·Affects liver, reproductive
A gasoline-derived industrial solvent and IARC Group 1 known human carcinogen. The most-feared VOC in groundwater, linked to leukemia at chronic exposure.
C₆H₆
EPA limit
0.005 mg/L (MCL)
Most at risk
Households on private wells near gas stations, refineries, or industrial corridors
Found in
City water · Well water · Industrial areas
AquaOx filters
YesActivated coconut shell carbon
What it does to you
Health effects
Benzene is classified by the International Agency for Research on Cancer as a Group 1 known human carcinogen, the highest category. Chronic exposure causes acute myeloid leukemia (AML) and is associated with other blood and bone-marrow cancers including non-Hodgkin lymphoma and aplastic anemia. The toxicity targets blood-forming tissue: benzene is metabolized in the liver to compounds that damage bone marrow stem cells.
Short of cancer, sustained benzene exposure suppresses red and white blood cell counts and weakens the immune system. Acute exposure at high concentrations causes dizziness, headaches, and central nervous system effects.
The EPA set the maximum contaminant level goal at zero because no exposure to a known carcinogen is considered safe. The enforceable MCL of 5 ppb reflects what current treatment technology can reliably achieve, not a "safe" threshold.
Where it comes from
How it gets into your water
Benzene enters drinking water primarily through petroleum contamination. Leaking underground storage tanks at gas stations are the single largest source nationwide; the EPA estimates hundreds of thousands of historical and active leak sites in the United States. Benzene is one of the BTEX compounds (benzene, toluene, ethylbenzene, xylenes) that make up roughly 1 to 2 percent of gasoline by volume.
Other pathways include refinery and petrochemical discharge, industrial solvent use, and oil-spill cleanup zones. Benzene is also present in cigarette smoke and forms during combustion, so urban stormwater runoff carries trace amounts into surface water.
Once in groundwater, benzene moves quickly and degrades slowly under typical aquifer conditions, so a leak can affect wells over a wide area for years.
Gas stations
Leaking underground storage tanks
Refineries & petrochemical
Process discharge and spills
Contaminated wells
Common in industrial corridors
Fuel spills
Pipeline and transport accidents
Find out for yourself
Is it in your water?
Public water utilities are required to test for benzene and report results in the annual Consumer Confidence Report. Most municipal systems report non-detect, but utilities drawing on contaminated aquifers occasionally show measurable levels.
Private well owners face the bigger risk. If your well is within a few thousand feet of a current or former gas station, fuel terminal, refinery, or industrial site, request a VOC panel that includes benzene. State environmental agencies maintain databases of known leaking underground storage tank (LUST) sites you can check by address.
The fix
How AquaOx filters it
Activated carbon is the EPA's recommended best-available technology for filtering benzene from drinking water. The Centaur catalytic carbon and coconut shell activated carbon stages in The AquaOx adsorb benzene as water flows through, with independent testing showing reductions above 95 percent across the BTEX family.
For households on known contaminated wells, we recommend pairing The AquaOx with the under-sink RO at the kitchen tap for a second-stage barrier on drinking and cooking water.