MTBE

Angola Pump District

MTBE was used as gasoline oxygenation additive to boost the octane number. In 2005, MTBE was replaced by ethanol as a gasoline additive. MTBE causes cancers in rats.

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Samples

Samples exceeding legal limit (MCL)

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2014	ND	5	0	ND
2015	ND	3	0	ND
2016	0.243 ppb	7	2	ND - 1.13 ppb
2017	0.653 ppb	6	4	ND - 1.53 ppb
2018	0.346 ppb	5	2	ND - 1.02 ppb
2019	0.530 ppb	9	4	ND - 1.28 ppb

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 13 ppb

The EWG Health Guideline of 13 ppb for MTBE was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.

ppb = parts per billion

All test results

Date	Lab ID	Result
2014-01-30	S438310	ND
2014-04-30	S479081	ND
2014-07-16	L5163369-1	ND
2014-09-24	S481386	ND
2014-09-24	S479246	ND
2015-08-26	S602018	ND
2015-09-22	S602047	ND
2015-09-22	S602046	ND
2016-07-20	S614692	1.13 ppb
2016-07-20	S614689	ND
2016-07-20	S614690	ND
2016-07-20	S614691	ND
2016-09-23	S670411	ND
2016-09-23	S670389	0.570 ppb
2016-10-19	S614695	ND
2017-01-24	S670503	0.560 ppb
2017-04-25	S730782	ND
2017-07-25	S679347	1.53 ppb
2017-09-21	S730869	0.650 ppb
2017-09-21	S730837	ND
2017-10-23	S769406	1.18 ppb
2018-01-23	S730855	ND
2018-07-26	S811985	1.02 ppb
2018-09-21	S812493	ND
2018-09-21	S812489	ND
2018-11-09	S812579	0.710 ppb
2019-01-17	S770888	1.23 ppb
2019-04-29	S847991	1.28 ppb
2019-07-24	S770597	ND
2019-07-24	S770595	ND
2019-07-24	S770592	ND
2019-07-24	S770588	1.21 ppb
2019-09-19	S864741	ND
2019-09-19	S864737	ND
2019-10-03	S919889	1.05 ppb