CHEYENNE, Wyo. – 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.