MTBE
Emerald Lake
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.
24
Samples
0
Samples exceeding legal limit (MCL)
0
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2014 | 0.160 ppb | 5 | 1 | ND - 0.800 ppb |
| 2015 | 0.233 ppb | 3 | 1 | ND - 0.700 ppb |
| 2016 | ND | 3 | 0 | ND |
| 2017 | 0.300 ppb | 4 | 2 | ND - 0.700 ppb |
| 2018 | 0.278 ppb | 6 | 3 | ND - 0.610 ppb |
| 2019 | 0.227 ppb | 3 | 1 | ND - 0.680 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 |
|---|---|---|
| 2014-07-16 | 133667.02 | ND |
| 2014-10-15 | 136900.03 | ND |
| 2014-10-15 | 136900.05 | 0.800 ppb |
| 2014-10-15 | 136900.02 | ND |
| 2014-10-15 | 136900.01 | ND |
| 2015-10-19 | 149265.01 | ND |
| 2015-10-19 | 149265.02 | ND |
| 2015-10-19 | 149265.03 | 0.700 ppb |
| 2016-12-13 | 163860.01 | ND |
| 2016-12-13 | 163860.02 | ND |
| 2016-12-13 | 163860.03 | ND |
| 2017-02-21 | 165820.01 | 0.700 ppb |
| 2017-10-02 | 174061.01 | ND |
| 2017-10-02 | 174061.02 | ND |
| 2017-11-09 | 175754.01 | 0.500 ppb |
| 2018-02-22 | 179061.03 | 0.500 ppb |
| 2018-04-03 | 180124.03 | 0.610 ppb |
| 2018-08-07 | 185103.03 | 0.560 ppb |
| 2018-10-15 | 187909.01 | ND |
| 2018-10-15 | 187909.02 | ND |
| 2018-10-15 | 187909.03 | ND |
| 2019-10-11 | 201688.01 | ND |
| 2019-10-11 | 201688.02 | ND |
| 2019-10-11 | 201688.03 | 0.680 ppb |