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EWG Statement, 03/10/2008

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NATIONAL SUMMARY

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CONTAMINANTS DATABASE

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Status: Unregulated - EPA has not established a maximum legal limit in tapwater for this contaminant.

Chloromethane is a by-product of water disinfection and an EPA top priority for testing and study in tap water based on toxicity concerns. It is also an industrial chemical used in manufacture of silicone, rubber, pesticides, and more; was formerly used as refrigerant, now banned; is an industry and municipal wastewater pollutant; and is produced naturally in small quantities. Potential health impacts associated with Chloromethane include cancer, cardiovascular or blood toxicity, developmental toxicity, gastrointestinal or liver toxicity, kidney toxicity, neurotoxicity, reproductive toxicity, respiratory toxicity, and skin sensitivity.

Sources of Chloromethane:

	Industry
	Water Treatment and Distribution Byproducts (pipes and fixtures, treatment chemicals and byproducts)
	Naturally Occurring (naturally present but increased for lands denuded by sprawl, agriculture, or industrial development)

An Environmental Working Group analysis of Chloromethane tests reported by 25,761 public water suppliers in 38 states shows that between 1998 and 2003, 6.3 million people in 977 communities drank water contaminated with Chloromethane. In 3 of these communities, tap water was contaminated at levels above health-based thresholds. Chloromethane remains unregulated in tap water, without a maximum legal limit.

Exposure Summary

6,262,579 People drinking water contaminated with Chloromethane 977 Communities served water contaminated with Chloromethane 511 People drinking water contaminated with Chloromethane over health based limits 3 Communities served water with Chloromethane above health based limits

Table. Chloromethane Exposure by State

511 Americans in 1 states were served tap water contaminated with Chloromethane at levels above health-based limits between 1998 and 2003.

State	Water suppliers with Chloromethane contamination		Water suppliers reporting Chloromethane above health-based limits
	Systems	Population	Systems	Population
Texas	421	1,158,851	3	511
Tennessee	83	1,091,940	0	0
California	18	825,416	0	0
Nebraska	5	567,591	0	0
Indiana	23	407,127	0	0
Alabama	45	372,083	0	0
Florida	4	289,584	0	0
North Carolina	77	274,489	0	0
Wisconsin	41	227,250	0	0
Delaware	7	211,829	0	0
Illinois	58	125,293	0	0
Iowa	3	121,912	0	0
New Jersey	7	108,974	0	0
Washington	12	98,059	0	0
Arkansas	41	92,129	0	0
Pennsylvania	11	69,245	0	0
Ohio	16	38,663	0	0
Alaska	14	37,611	0	0
Nevada	5	27,829	0	0
Maine	14	25,211	0	0
Idaho	6	22,670	0	0
New Hampshire	12	19,903	0	0
New Mexico	12	18,451	0	0
Utah	3	9,597	0	0
Minnesota	4	5,385	0	0
Colorado	8	5,042	0	0
Oklahoma	13	5,034	0	0
New York	6	4,264	0	0
Arizona	1	450	0	0
South Carolina	3	259	0	0
South Dakota	1	188	0	0
Montana	2	160	0	0
Virginia	1	90	0	0
Total	977	6,262,579	3	511

Table. The most polluted communities

511 Americans in 3 communities were served tap water contaminated with Chloromethane above health based limits between 1998 and 2003

Ranked by highest average Chloromethane level

Rank	System	Population Served	Positive test results of total reported tests	Average Level (Range)
1	Riley Road Estates Ws HOUSTON, TX	1	1 of 1	81 ppb (81 to 81 ppb)
2	Garden Acres Subdivision Water System Dallas, TX	96	2 of 3	45.97 ppb (0 to 135 ppb)
3	Watson Lake Water System Huntsville, TX	414	1 of 2	31 ppb (0 to 62 ppb)

Health based limits for Chloromethane

Health Limit	Limit Value	Limit Description
Children's health-based limit for 1-day exposure	9000 ppb	Concentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic health effects for up to one day of exposure. The One-Day health-based limit (or Health Advisory, HA) is typically set to protect a 10-kg child consuming 1 liter of water per day. Source: U.S. Environmental Protection Agency.
Children's health-based limit for 10-day exposure	400 ppb	Concentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic effects for up to ten days of exposure. The Ten-Day health-based limit (or Health Advisory, HA) is typically set to protect a 10-kg child consuming 1 liter of water per day. Source: U.S. Environmental Protection Agency.
Lifetime health-based limit, non-cancer risk	30 ppb	Concentration of a chemical in drinking water that is not expected to cause any adverse, noncarcinogenic health effects for a lifetime of exposure. The Lifetime health-based limit (or Health Advisory, HA) is based on exposure for a a 70-kg adult consuming 2 liters of water per day. Source: U.S. Environmental Protection Agency.
Drinking Water Equivalent Level	100 ppb	A lifetime exposure concentration protective of adverse, noncarcinogenic health effects, that assumes all of the exposure to a contaminant is from drinking water. Source: U.S. Environmental Protection Agency.

Testing Summary for Chloromethane

Water suppliers report an average of 0.7 Chloromethane tests per year. 13,990 water suppliers failed to report any Chloromethane tests at all.

Are tests routinely required for Chloromethane by federal law? No Water suppliers reporting tests for Chloromethane (1998-2003): 25,761 of 39,751 Average testing rate for water supplier reporting tests (1998-2003): 0.7 per year

Chloromethane Violations

Because Chloromethane is unregulated in tap water, no violations are recorded in EPA's violations database, the Safe Drinking Water Information System. Under the federal tap water law, water suppliers are not required to routinely test for Chloromethane, and any level is legal in tap water.