MTBE

Middleborough Water Supply

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	11	0	ND
2015	ND	10	0	ND
2016	ND	9	0	ND
2017	0.1000 ppb	11	1	ND - 1.10 ppb
2018	ND	10	0	ND
2019	ND	9	0	ND

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	Result
2014-02-12	ND
2014-02-12	ND
2014-02-12	ND
2014-02-12	ND
2014-02-12	ND
2014-02-12	ND
2014-02-12	ND
2014-02-12	ND
2014-05-09	ND
2014-05-30	ND
2014-06-23	ND
2015-01-20	ND
2015-03-11	ND
2015-03-11	ND
2015-03-11	ND
2015-03-11	ND
2015-03-11	ND
2015-03-11	ND
2015-03-23	ND
2015-04-27	ND
2015-04-27	ND
2016-03-08	ND
2016-03-08	ND
2016-03-09	ND
2016-03-10	ND
2016-03-10	ND
2016-03-10	ND
2016-03-11	ND
2016-03-21	ND
2016-07-28	ND
2017-02-14	ND
2017-02-14	ND
2017-02-14	ND
2017-02-14	ND
2017-02-14	ND
2017-02-14	1.10 ppb
2017-02-15	ND
2017-02-27	ND
2017-05-09	ND
2017-05-09	ND
2017-05-09	ND
2018-02-08	ND
2018-02-08	ND
2018-02-08	ND
2018-02-08	ND
2018-02-08	ND
2018-02-08	ND
2018-02-08	ND
2018-02-08	ND
2018-05-10	ND
2018-05-10	ND
2019-02-13	ND
2019-02-13	ND
2019-02-13	ND
2019-02-13	ND
2019-02-13	ND
2019-02-13	ND
2019-04-16	ND
2019-04-16	ND
2019-10-22	ND