Industrial chemicals
Industrial chemicals in tap water, often called VOCs or volatile organic compounds, come from fuel leaks, dry cleaners, degreasers, factories and old farm fumigants. A home water test checks 55 of them, and each has its own Science and Health line, such as 0.15 ppb for benzene. A carbon filter certified for VOC reduction is the household fix for nearly all of them.
Science and Health line for 1,2,3-TCP, the strictest here
0.0007 ppb
A home water test checks 55 of these chemicals, from fuel to dry-cleaning solvents. Each keeps its own Science and Health line.
Industrial chemicals: what is it, and where does it come from?
Volatile organic compounds are carbon-based chemicals that evaporate easily.
The ones a water test checks are industrial: the benzene, toluene and xylenes in fuel, the chlorinated solvents that dry cleaners and metal shops used for decades, the fumigants once used on farm soil, and a handful of refrigerants and plastics chemicals.
They reach drinking water when they leak or leach into the ground and then into the wells or rivers a utility draws from. Groundwater supplies are the usual place to find them, and a well near an old fuel station, dry cleaner or orchard is the classic case.
Industrial chemicals: why does it matter?
Several of these chemicals cause cancer.
EPA lists a higher cancer risk from long-term exposure to benzene, TCE, PCE, carbon tetrachloride, 1,2-dichloroethane and dichloromethane, and vinyl chloride is a known cause of liver cancer. Others harm the liver, kidneys or nervous system at high levels over years.
Because the cancer-causing ones carry health goals set at one extra case per million people over a lifetime, their Science and Health lines sit well below the legal limits. That gap is the reason we grade to the health research rather than to the law.
EPA lists an increased risk of cancer from long-term exposure above the legal limit for benzene, trichloroethylene, tetrachloroethylene, carbon tetrachloride, 1,2-dichloroethane, dichloromethane, 1,2-dichloropropane, ethylene dibromide and DBCP, and names vinyl chloride's source as leaching from PVC pipe and plastics factories.
US EPA, National Primary Drinking Water Regulations (organic chemicals)
California's public health goal for 1,2,3-trichloropropane is 0.0007 ppb, among the lowest health goals for any drinking-water chemical, set on cancer in animal studies.
California State Water Resources Control Board, MCLs/DLRs/PHGs table (updated September 2025)
EPA calls granular activated carbon a proven technology with high removal of many volatile organic compounds, including TCE and PCE.
In peer-reviewed bench tests, low-pressure reverse osmosis rejected only a small share of small chlorinated solvents such as dichloromethane and 1,2-dichloroethane, while activated carbon removed them effectively.
Low-pressure reverse osmosis rejection of volatile halogenated organics, Membranes 11(1):33, 2021
Fuel chemicals: benzene, toluene, xylenes and MTBE
Fuel chemicals reach groundwater from leaking fuel tanks, refineries and spills. A home water test checks the ones below. Benzene is the one that matters most: it causes leukemia, and its Science and Health line is a small fraction of the legal limit.
Where they come from. Leaking underground fuel tanks, refineries and fuel spills.
The fix. A carbon filter certified for VOC reduction under NSF/ANSI 53, the certification for health-related filter claims. Check that the listing names the chemical. Reverse osmosis on its own is weak on these small molecules.
| Substance | Science and Health line | Why it matters |
|---|---|---|
| Benzene | 0.15 ppb | A known cause of leukemia; long-term exposure also causes anemia. |
| Toluene | 150 ppb | Long-term exposure at high levels harms the nervous system, kidneys or liver. |
| Ethylbenzene | 300 ppb | Long-term exposure at high levels harms the liver or kidneys. |
| Xylenes, meta and para Lab reports may say: m,p Xylene, m,p-Xylene | 1,750 ppb | Long-term exposure at high levels damages the nervous system. |
| Xylene, ortho Lab reports may say: o Xylene, o-Xylene | 1,750 ppb | Long-term exposure at high levels damages the nervous system. |
| MTBE Lab reports may say: Methyl Tertiary Butyl Ether, Methyl tert-butyl ether | 13 ppb | A gasoline additive that gives water a taste and smell even below its health line. |
| Naphthalene | 17 ppb | California lists it as a cause of cancer; its drinking-water line comes from animal studies. |
| 1,2,4-Trimethylbenzene Lab reports may say: 1,2,4 Trimethylbenzene | 330 ppb | Its line comes from effects seen in animal studies. |
| 1,3,5-Trimethylbenzene Lab reports may say: 1,3,5 Trimethylbenzene | 330 ppb | Its line comes from effects seen in animal studies. |
| Isopropylbenzene (cumene) Lab reports may say: Isopropylbenzene, Cumene | 770 ppb | Its line comes from kidney effects in animal studies. |
| n-Propylbenzene Lab reports may say: n Propylbenzene | 260 ppb | Its line borrows from a related chemical's kidney effects in animal studies. |
| n-Butylbenzene Lab reports may say: n Butylbenzene | 260 ppb | Its line borrows from a related chemical's kidney effects in animal studies. |
| sec-Butylbenzene Lab reports may say: sec Butylbenzene | 260 ppb | Its line borrows from a related chemical's kidney effects in animal studies. |
| tert-Butylbenzene Lab reports may say: tert Butylbenzene | 260 ppb | Its line borrows from a related chemical's kidney effects in animal studies. |
| p-Isopropyltoluene (p-cymene) Lab reports may say: p Isopropyltoluene, p-Cymene | None set | No agency sets a drinking-water line for it. |
Chlorinated solvents and degreasers, one by one
Chlorinated solvents come from dry cleaners, metal degreasing and factories, and they sink into groundwater. Several cause cancer, which is why the Science and Health lines for TCE, PCE and vinyl chloride sit well below the legal limits.
Where they come from. Dry cleaners, metal degreasing sites and factories.
The fix. A carbon filter certified for VOC reduction under NSF/ANSI 53, the certification for health-related filter claims. Check that the listing names the chemical. Reverse osmosis on its own is weak on these small molecules.
| Substance | Science and Health line | Why it matters |
|---|---|---|
| TCE (trichloroethylene) Lab reports may say: Trichloroethylene, TCEFull page: Chlorinated solvents (TCE, PCE) | 1.7 ppb | Long-term exposure causes liver problems and raises cancer risk. |
| PCE (tetrachloroethylene) Lab reports may say: Tetrachloroethylene, Perchloroethylene, PCE, PercFull page: Chlorinated solvents (TCE, PCE) | 0.06 ppb | Long-term exposure causes liver problems and raises cancer risk. |
| 1,1-Dichloroethene Lab reports may say: 1,1 Dichloroethylene, 1,1-Dichloroethylene, Vinylidene chlorideFull page: Chlorinated solvents (TCE, PCE) | 6 ppb | Long-term exposure at high levels causes liver problems. |
| cis-1,2-Dichloroethene Lab reports may say: cis 1,2 Dichloroethylene, cis-1,2-Dichloroethylene | 6 ppb | Long-term exposure at high levels causes liver problems. |
| Vinyl chloride Lab reports may say: Vinyl Chloride, Chloroethene | 0.05 ppb | A known cause of liver cancer. PVC pipe and plastics factories. |
| 1,1,1-Trichloroethane Lab reports may say: 1,1,1 Trichloroethane, Methyl chloroform | 200 ppb | Long-term exposure at high levels harms the liver, nervous system or circulation. |
| 1,1,2-Trichloroethane Lab reports may say: 1,1,2 Trichloroethane | 0.3 ppb | Long-term exposure at high levels harms the liver, kidneys or immune system. |
| 1,1-Dichloroethane Lab reports may say: 1,1 Dichloroethane | 3 ppb | A solvent; its line is California's public health goal. |
| 1,2-Dichloroethane Lab reports may say: 1,2 Dichloroethane, Ethylene dichloride | 0.4 ppb | Long-term exposure raises cancer risk. |
| 1,1,1,2-Tetrachloroethane Lab reports may say: 1,1,1,2 Tetrachloroethane | 70 ppb | EPA considers it a possible cause of cancer. |
| 1,1,2,2-Tetrachloroethane Lab reports may say: 1,1,2,2 Tetrachloroethane | 0.1 ppb | EPA considers it a likely cause of cancer. |
| Carbon tetrachloride Lab reports may say: Carbon Tetrachloride | 0.1 ppb | Long-term exposure causes liver problems and raises cancer risk. Chemical plants and other industry. |
| Dichloromethane (methylene chloride) Lab reports may say: Dichloromethane, Methylene chloride | 4 ppb | Long-term exposure causes liver problems and raises cancer risk. Drug and chemical factories. |
| Chloroethane Lab reports may say: Ethyl chloride | None set | No agency sets a drinking-water line for it. |
| Chloromethane Lab reports may say: Methyl chloride | 28 ppb | No agency sets a drinking-water line for it. |
Chlorobenzenes and related industrial chemicals
Chlorobenzenes come from chemical, pesticide and textile factories. Their Science and Health lines run from 5 ppb for 1,4-dichlorobenzene to 600 ppb for 1,2-dichlorobenzene, most of them far above the solvents in the group above.
Where they come from. Industrial chemical, agricultural chemical and textile factories.
The fix. A carbon filter certified for VOC reduction under NSF/ANSI 53, the certification for health-related filter claims. Check that the listing names the chemical. Reverse osmosis on its own is weak on these small molecules.
| Substance | Science and Health line | Why it matters |
|---|---|---|
| Chlorobenzene Lab reports may say: Monochlorobenzene | 70 ppb | Long-term exposure at high levels harms the liver or kidneys. |
| 1,2-Dichlorobenzene Lab reports may say: 1,2 Dichlorobenzene, o-Dichlorobenzene | 600 ppb | Long-term exposure at high levels harms the liver, kidneys or circulation. |
| 1,3-Dichlorobenzene Lab reports may say: 1,3 Dichlorobenzene, m-Dichlorobenzene | 600 ppb | Its line comes from liver effects in animal studies. |
| 1,4-Dichlorobenzene Lab reports may say: 1,4 Dichlorobenzene, p-Dichlorobenzene | 5 ppb | Long-term exposure at high levels causes anemia and harms the liver, kidneys or spleen. |
| 1,2,4-Trichlorobenzene Lab reports may say: 1,2,4 Trichlorobenzene | 5 ppb | Long-term exposure at high levels changes the adrenal glands. |
| 1,2,3-Trichlorobenzene Lab reports may say: 1,2,3 Trichlorobenzene | None set | No agency sets a drinking-water line for it. |
| Hexachlorobutadiene | 0.6 ppb | EPA considers it a likely cause of cancer, but no agency sets a drinking-water line for it. |
| Bromobenzene | 60 ppb | Its line comes from liver effects in animal studies. |
| 2-Chlorotoluene Lab reports may say: Chlorotoluene 2, o-Chlorotoluene | 100 ppb | Its line comes from effects seen in animal studies. |
| 4-Chlorotoluene Lab reports may say: Chlorotoluene 4, p-Chlorotoluene | 100 ppb | Its line comes from effects seen in animal studies. |
Soil fumigants: DBCP, EDB and 1,2,3-TCP
Soil fumigants were used on farm and orchard soil to kill pests, and they can leach into groundwater. They include the strictest Science and Health lines on the whole test, down to 0.0007 ppb for 1,2,3-trichloropropane, because their health goals are set for cancer risk.
Where they come from. Soil fumigants used on farms and orchards, plus refineries and industrial waste.
The fix. A carbon filter certified for VOC reduction under NSF/ANSI 53, the certification for health-related filter claims. Check that the listing names the chemical. Reverse osmosis on its own is weak on these small molecules.
| Substance | Science and Health line | Why it matters |
|---|---|---|
| 1,2,3-Trichloropropane (TCP) Lab reports may say: 1,2,3 Trichloropropane, 1,2,3-TCP, TCP | 0.0007 ppb | Causes cancer in animal studies at many sites, which is why its line is so low. |
| DBCP (dibromochloropropane) Lab reports may say: Dibromochloropropane, 1,2-Dibromo-3-chloropropane, DBCP | 0.003 ppb | Long-term exposure causes reproductive problems and raises cancer risk. |
| EDB (ethylene dibromide) Lab reports may say: Ethylene dibromide, 1,2-Dibromoethane, EDB | 0.01 ppb | Long-term exposure harms the liver, stomach, reproductive system or kidneys and raises cancer risk. Refineries, and its past use as a soil fumigant. |
| 1,2-Dichloropropane Lab reports may say: 1,2 Dichloropropane | 0.5 ppb | Long-term exposure raises cancer risk. |
| cis-1,3-Dichloropropene Lab reports may say: cis 1,3 Dichloropropene | 0.2 ppb | Causes bladder tumors in animal studies. |
| trans-1,3-Dichloropropene Lab reports may say: trans 1,3 Dichloropropene | 0.2 ppb | Causes bladder tumors in animal studies. |
| Bromomethane (methyl bromide) Lab reports may say: Bromomethane, Methyl bromide | 10 ppb | A fumigant; its line is EPA's lifetime health advisory. |
| 1,3-Dichloropropane Lab reports may say: 1,3 Dichloropropane | 100 ppb | No agency sets a drinking-water line for it. |
| 2,2-Dichloropropane Lab reports may say: 2,2 Dichloropropane | None set | No agency sets a drinking-water line for it. |
| 1,1-Dichloropropene Lab reports may say: 1,1 Dichloropropene | None set | No agency sets a drinking-water line for it. |
Refrigerants, styrene and other industrial chemicals
The last group is a mix: two older refrigerants, styrene from plastics, and a few chemicals that show up on the same lab method. Styrene carries the lowest Science and Health line of these, 0.5 ppb.
Where they come from. Industrial and commercial releases, and landfills.
The fix. A carbon filter certified for VOC reduction under NSF/ANSI 53, the certification for health-related filter claims. Check that the listing names the chemical. Reverse osmosis on its own is weak on these small molecules.
| Substance | Science and Health line | Why it matters |
|---|---|---|
| Styrene | 0.5 ppb | Long-term exposure at high levels harms the liver, kidneys or circulation. Rubber and plastics factories, and landfills. |
| Dichlorodifluoromethane (Freon 12) Lab reports may say: Dichlorodifluoromethane, Freon 12, CFC-12 | 1,000 ppb | An older refrigerant; its line comes from effects seen in animal studies. |
| Trichlorofluoromethane (Freon 11) Lab reports may say: Trichlorofluoromethane, Freon 11, CFC-11 | 150 ppb | An older refrigerant; its line is California's legal limit. |
| Bromochloromethane | 90 ppb | Its line is EPA's lifetime health advisory. |
| Dibromomethane Lab reports may say: Methylene bromide | None set | No agency sets a drinking-water line for it. |
What helps against Industrial chemicals?
The approaches below are the ones people use for Industrial chemicals at home. Each entry says what it does and what it cannot do, and not every one helps.
Direct fixes
Carbon filter certified for VOC reduction (NSF/ANSI 53)
Activated carbon adsorbs these chemicals, and it is the household fix for nearly every row on this page. An under-sink carbon block covers drinking and cooking water.
Check that the listing names the chemical you need removed, and replace the cartridge on schedule: a spent carbon filter stops working without any change you can see or taste.
Bigger retrofits
Whole-house carbon (point-of-entry)
Treats every tap, which matters for chemicals that evaporate from hot water in the shower.
A bigger install with its own maintenance; size it to your water use and the chemical found.
Common questions about Industrial chemicals
Where do solvents and fuel chemicals in tap water come from?
From leaks and spills into the ground: fuel tanks, dry cleaners, metal degreasing shops, factories, landfills and fumigated farm soil. They then reach the groundwater a utility or a private well draws from. They are not added in treatment.
Does a regular carbon pitcher remove VOCs?
Only if it is certified for VOC reduction, and only for the chemicals its listing names. Carbon is the right technology for this group, but certification is claim by claim, so check the listing before you rely on it.
Why are the lines for some of these chemicals so low?
Because their health goals are set for cancer risk, at one extra case per million people over a lifetime. That is why the Science and Health line for 1,2,3-trichloropropane is 0.0007 ppb, below what labs can measure, so any confirmed detection is flagged.
Sources cited for Industrial chemicals
Every number on this Industrial chemicals page traces to one of the 7 sources below: 1 peer-reviewed, 5 government or regulatory.
Peer-reviewed
Government & regulatory
- US EPA, National Primary Drinking Water Regulations (organic chemicals)
- California State Water Resources Control Board, MCLs/DLRs/PHGs table (updated September 2025)
- US EPA, 2018 Edition of the Drinking Water Standards and Health Advisories Tables (EPA 822-F-18-001)
- California State Water Resources Control Board, Notification and Response Levels overview (June 2026)
- US EPA, Overview of Drinking Water Treatment Technologies
Institutional & standards