CHEYENNE, Wyo. (AP) - New groundwater testing in Wyoming shows lower levels of the carcinogen benzene than what the U.S. Environmental Protection Agency reported when it linked contaminants in two water wells to hydraulic fracturing, but only one well was tested this time.
Benzene is a hydrocarbon commonly associated with oil and gas development. Last year's testing by the EPA showed benzene at almost 50 times the recommended EPA limit. The new data released Wednesday by the U.S. Geological Survey show benzene at 3 percent of the recommended EPA limit.
This year's tests and the previous tests aren't an apples-to-apples comparison, however. Researchers this time around decided they couldn't get enough water for a reliable sample from one of the wells the EPA drilled to test for pollution near the rural community of Pavillion.
That low-flowing well had the very high benzene level. In the other well - the one researchers relied on for this year's testing - any amount of benzene in the groundwater tested was too small to be detected last year.
In that sense, the results for benzene this year are in line with last year's.
The results from this year's testing generally are "consistent with ground water monitoring data previously released," EPA spokeswoman Alisha Johnson said by email.
Environmental groups and Encana Corp., the Calgary-based petroleum company that operates the Pavillion gas field, declined to comment on the meaning behind the data released Wednesday, saying they needed more time to analyze the material.
Wyoming Gov. Matt Mead also said the state would need more time to review the data gathered in collaboration with the USGS, Wyoming, the EPA and two American Indian tribes.
"I feel that the process used to acquire this data was an improvement on the process used for the draft EPA report last December," Mead said in a news release.
One person each representing Wyoming, the EPA and the two tribes had the opportunity to view the data in advance and agreed not to discuss any of that information, according to Mead spokesman Renny MacKay.
The USGS released tables the amounts of dozens of chemicals without offering any analysis.
Benzene is not among the chemicals the EPA pointed to last year in making the link to hydraulic fracturing, commonly known as fracking. The process involved blasting millions of gallons of water mixed with sand and chemicals down well holes to crack open formations and improve the flow of oil and gas.
Wyoming officials and the petroleum industry criticized the draft EPA study released in December, characterizing its findings as flimsy. State officials were further incensed the EPA did not consult with them about the testing it was doing on their turf.
Last winter, Wyoming officials and the EPA mended fences and announced they would collaborate with the USGS and tribes on the new testing, which occurred over two days in late April.
Meanwhile, some Pavillion-area homeowners continue to complain about well water that became befouled by chemicals after gas drilling picked up in their neighborhood about seven years ago.
One environmentalist representing the affected residents wished for more official analysis to go with the reams of new data.
"A better interpretation of the data would have been beneficial for the impacted residents and the public," Deb Thomas, with the Powder River Basin Resource Council, said by email.
Encana spokesman Doug Hock said the fact that one of the wells didn't produce enough water to use for the new testing casts doubt on the previous testing.
"EPA's wells are improperly constructed," he said by email.
Encana will comment on the results after it had more time to review them, he said.
A full peer review of the sampling and findings to date will occur later.