article_snippet.sent: The oil and gas industry uses injection wells to get rid of wastewater, which can have chemicals, heavy metals, salt and radioactive material.
article_snippet.sent: Massive amounts of brine taken out of the ground with the gas, said study co-author William Ellsworth of the USGS.
article_snippet.sent: But the deep injection of the wastes still is the principle culprit, study co-author William Ellsworth of the USGS said.
highlights_snippet.sent: Scientists say this is the result of injecting wastewater into the ground .
  