Peoples Gas

What it means: Benzo(a)pyrene (BaP) is a polycyclic aromatic hydrocarbon (PAH) formed during incomplete combustion of organic material. It enters drinking water primarily through leaching from coal tar linings in older water storage tanks and distribution pipes, as well as from contaminated soil and industrial runoff. It is one of the most studied PAHs due to its potent carcinogenicity.

Health effects: Benzo(a)pyrene is classified by EPA as a probable human carcinogen (Group B2) and is a well-established animal carcinogen. Long-term exposure is associated with increased cancer risk, particularly for reproductive organ cancers. It is also linked to immune system effects and developmental toxicity in animal studies.

Limit: 0.0002 mg/L (0.2 ppb)

What it means: Dalapon is an organochlorine herbicide used to control grassy weeds in sugarcane, corn, and other crops, as well as along roadsides and waterways. It remains in agricultural use in the United States. It reaches water primarily through agricultural runoff and leaching.

Health effects: Long-term exposure to dalapon is associated with liver and kidney effects in animal studies. EPA has not classified it as a human carcinogen based on available data. The general population is the primary concern for chronic low-level exposure through drinking water.

Limit: 0.2 mg/L (200 ppb)

What it means: Di(2-ethylhexyl) adipate (DEHA) is a synthetic plasticizer used to make PVC and other plastics flexible. It enters drinking water through discharge from chemical factories and leaching from PVC plastic materials including some water distribution components. It is one of the less commonly detected regulated organic contaminants in US public water systems.

Health effects: Chronic exposure to DEHA is associated with reproductive effects and decreased body weight in animal studies. EPA classifies it as a possible human carcinogen (Group C). Long-term exposure above the MCL is the primary concern; the general population is at risk, with potential for greater sensitivity in developing fetuses and reproductive-age adults.

Limit: 0.4 mg/L (400 ppb)

What it means: Di(2-ethylhexyl) phthalate (DEHP) is the most widely used plasticizer in PVC products including pipes, flooring, medical tubing, and food packaging. It enters drinking water through discharge from rubber and chemical factories and leaching from PVC water distribution materials. It is one of the more commonly detected phthalates in US drinking water.

Health effects: Chronic exposure to DEHP is associated with reproductive and developmental toxicity — it acts as an endocrine disruptor and can interfere with hormone signaling. EPA classifies it as a probable human carcinogen (Group B2) based on animal liver tumor data. Developing fetuses, infants, and reproductive-age adults are most susceptible to its hormonal effects.

Limit: 0.006 mg/L (6 ppb)

What it means: Dinoseb is a dinitrophenol herbicide and pesticide formerly used on crops including soybeans, cereals, and vegetables. Its US pesticide registrations were voluntarily canceled in 1986 after it was found to cause severe reproductive and developmental toxicity. It persists in soil and can leach into groundwater from historically treated agricultural fields.

Health effects: Dinoseb uncouples oxidative phosphorylation, disrupting cellular energy production. Chronic exposure causes reproductive toxicity: impaired sperm production in males and developmental harm, including birth defects, in developing fetuses. EPA has not established a formal carcinogenicity classification. Reproductive-age adults and pregnant women face the greatest risk.

Limit: 0.007 mg/L (7 ppb)

What it means: Endrin was a cyclodiene organochlorine insecticide and rodenticide used primarily on field crops such as cotton, grains, and sugarcane. It was banned in the United States in 1991. Endrin is highly persistent in soil and binds strongly to sediment, meaning legacy contamination in groundwater and surface water can persist decades after use.

Health effects: Endrin is acutely toxic to the nervous system and can cause seizures, headache, dizziness, and liver damage at high doses. Chronic low-level exposure is associated with liver and nervous system effects. EPA classifies it as a possible human carcinogen (Group C). Children and the elderly are most vulnerable to acute neurological effects.

Limit: 0.002 mg/L (2 ppb)

What it means: Hexachlorobenzene (HCB) is a chlorinated aromatic compound formerly used as a fungicide on grain seeds and as an industrial chemical. All pesticide uses were canceled in the United States by 1984. It is also produced as a byproduct in the manufacture of certain chlorinated solvents and pesticides. HCB is highly persistent and bioaccumulates in fatty tissue and sediment.

Health effects: Chronic exposure to hexachlorobenzene is associated with liver damage, skin lesions, and neurological effects. EPA classifies it as a probable human carcinogen (Group B2). It can be transferred to infants through breast milk. Reproductive and developmental toxicity have been observed in animal studies.

Limit: 0.001 mg/L (1 ppb)

What it means: Hexachlorocyclopentadiene (HCCP) is a chlorinated cyclic compound used as a chemical intermediate in the manufacture of pesticides, flame retardants, and resins. It is not used directly as a pesticide. It enters drinking water through discharge from chemical manufacturing facilities. It is reactive and degrades relatively quickly in the environment.

Health effects: Chronic exposure to hexachlorocyclopentadiene is associated with kidney and stomach damage in animal studies. EPA has not classified it as a human carcinogen based on available data. Short-term high-level exposure may cause irritation of mucous membranes. Long-term exposure above the MCL is the primary concern for public water system violations.

Limit: 0.05 mg/L (50 ppb)