Improper storage and waste disposal; leaking underground fuel storage tanks; manufacture of pesticides, solvents; pretroleum refining; cigarette smoke.

0.005 mg/l MCL

Can be absorbed through skin and is associated with leukemia; causes cancer in rats and is a known carcinogen. Microorganisms slowly biodegrade it in soil and water.

Improper storage and waste disposal; no natural sources; manufacture of chlorofluoromethane; grain fumigants; fire extinguishers; cleaning agents.

0.005 mg/l MCL

Known to cause cancer in lab animals; also damages liver, kidneys, and visual problems; confirmed carcinogen; exhibits extreme toxicity to mammals.

Improper storage and waste disposal; dry cleaning solvent; metal degreasers; adhesives; fumigants; paint varnish; gasoline additive.

0.005 mg/l MCL

Affects lab animals causing cancerous tumors in stomach, circulatory system, lungs and mammary glands; likely human carcinogen.

Improper storage and waste disposal; no natural sources.

0.007 mg/l MCL

In lab animals causes liver and kidney damage; may be carcinogenic but very little evidence.

Improper storage and waste disposal; no natural sources.

0.20 mg/l MCL

Known to irritate eyes and mucous membranes; in lab animals causes liver, nervous and circulatory system damage with similar problems in humans.

Improper storage and waste disposal; no natural sources.

0.075 mg/l MCL

Known to cause liver and kidney damage in lab animals; accumulates in human fatty tissues; limited evidence it is carcinogenic.

Improper waste disposal; solvents; transformed in drinking water from other chlorinated hydrocarbons; no natural sources.

0.07 mg/l MCL

Causes damage to liver, nervous and circulatory systems.

Agricultural runoff when used as soil fumigant and industrial waste discharge; industrial solvents and cleaning agents; soil fumigants; no natural sources.

0.005 mg/l MCL

In animal studies found to cause cancer, and liver and kidney damage; also causes symptoms like anemia, headache, and irritation of mucous membranes; possible human carcinogen.

Dichloromethane

0.005 mg/l MCL

Ethylbenzene

Leaking gasoline tanks or improper waste disposal; styrene production.

0.7 mg/l MCL

In lab animals causes damage to kidneys, liver and nervous system.

Monochlorobenzene

Improper waste disposal of solvent; mostly found in air; very little found in drinking water supplies; no natural sources.

0.1 mg/l MCL

Causes damage to liver, kidneys, and nervous system but insufficient data to classify as carcinogen.

o-dichlorobenzene

Improper waste disposal; no natural sources.

0.6 mg/l MCL

Causes damage to liver, kidneys, and blood cells, and nervous and circulatory systems.

Manufacture of plastics, synthetic rubbers, resins, insulators; sweet oriental gum plant; occasionally found in surface, ground, and drinking water supplies but uncommon; not very soluble in water.

0.1 mg/l MCL

Inhalation affects the nervous system and can cause abortion and birth defects; known to cause cancer in lab animals; a likely human carcinogen.

Industrial metal; dry cleaning solvents; manufacture of fluorocarbons; no natural sources.

0.005 mg/l MCL

Can cause damage to liver, kidneys, and central nervous system; causes cancer in lab animals; likely human carcinogen.

Leaking fuel storage tanks or improper waste disposal; found naturally in petroleum; solvent for point, oil, and resin manufacture.

1 mg/l MCL

Causes damage to liver, kidneys, and nervous and circulatory systems; may cause irritation of eyes, skin, and respiratory tract; bioaccumulates in some animals.

Improper waste disposal; can be transformed in drinking water from other chlorinated hydrocarbons; no natural sources.

0.1 mg/l MCL

Has anesthetic effects and causes damage to liver, and nervous and circulatory systems.

Improper storage and waste disposal; no natural sources.

0.005 mg/l MCL

Causes cancerous tumors in liver and lungs of lab mice; likely human carcinogen.

Improper storage or waste disposal; manufacture of plastics and synthetic rubber; no natural sources.

0.002 mg/l MCL

Known to cause cancer in lab animals and associated with cancer in humans; a known carcinogen; irritates skin and eyes.

Leaking underground fuel storage tanks; found naturally in petroleum; can be found in wood.

10 mg/l MCL

Causes damage to liver, kidneys, and nervous system.

In small quantities may be formed during chlorination process of drinking water treatment but not often found in finished water.

0.07 mg/l MCL

Causes liver and kidney damage, irritates eyes and mucous membranes and skin inflammation.

Can be long lived in the environment and is not degraded by biological organisms; has been found in treated and raw waters; no natural sources.

0.005 mg/l MCL

Causes damage to liver and kidneys and is irritating to eyes and mucous membranes.