HARRISBURG, Pa. -- Citing potentially unsafe drinking water, Pennsylvania is calling on companies drilling in the Marcellus Shale natural gas formation to stop taking wastewater to 15 treatment plants by May 19.
The Department of Environmental Protection took the major step Tuesday, citing elevated levels of bromide in rivers in western Pennsylvania where gas drilling has rapidly grown in the past three years.
Bromide, a salt, is present in drilling wastewater that is partially treated by sewer authorities and discharged into rivers that supply drinking water.
It reacts with chlorine disinfectants used by drinking water systems and creates trihalomethanes. That chemical can be harmful to people who drink water with elevated levels of trihalomethanes for many years.
In addition to gas drilling, other industrial sources are also a major factor in the high salt levels that lead to trihalomethanes in drinking water.