As if the historic four-year California megadrought isn’t bad enough, now state oil companies are risking polluting groundwater supplies by dumping their fracking waste into open unlined pits.

More than 900 fracking waste disposal pits dot the San Joaquin Valley, many of them in Kern County, and some of them sit directly on top of usable drinking water supplies.

In February, Kern County water officials discovered 300 unlined pits operated by oil companies without a license, and many of them sit next to farm land. Officials said none of the pits were lined and few had nets to prevent access from wildlife.

Then, Thursday, a new state-mandated study urged the waste water pits be closely monitored or stopped altogether. The new study by the Lawrence Berkeley National Laboratory said the danger of contamination was too great to be ignored.

“This is a source of contamination that needs to be managed. The water needs to be tested and treated, or the pits need to be closed.”

California also needs to better monitor and regulate where oil companies are drilling, especially when they’re near drinking water supplies, say the scientists.

LOST HILLS, CA - MARCH 23: Pump jacks are seen next to a canal in an oil field over the Monterey Shale formation where gas and oil extraction using hydraulic fracturing, or fracking, is on the verge of a boom on March 23, 2014 near Lost Hills, California. (Photo by David McNew/Getty Images)

Fracking uses high-pressure water blended with a mix of chemicals to blast open pockets of oil and natural gas that were previously inaccessible. The study’s authors worry the high-pressure water could break through and contaminate drinking water supplies.

Environmental groups are urging the governor to place a moratorium on fracking while more studies can be done to determine its effects. They say the process wastes millions of gallons of water, pollutes the environment, and threatens communities, and they’re pushing for a ban similar to the one enacted in New York.

SAN FRANCISCO, CA - MAY 30: Protestors stage a demonstration against fracking in California outside of the Hiram W. Johnson State Office Building on May 30, 2013 in San Francisco, California. (Photo by Justin Sullivan/Getty Images)

Jerry Brown’s refusal to place a ban on fracking has driven a rift between him and the state’s environmentalists who usually support the governor. The oil companies, however, are happy with Brown and maintain the process is safe and necessary to access hard to reach oil and natural gas supplies.

This study will probably do little to quell the argument between the two groups as both sides can claim some victories from the report.

The study’s authors did no research of their own, but merely analyzed data by other researchers. They found no evidence of groundwater contamination or proof that fracking causes earthquakes. The lead researcher, however, was quick to point out that very few of the studies analyzed actually tested drinking water supplies for contamination.

Until the situation changes fracking remains legal in California.

[Photo by David McNew/Justin Sullivan/David McNew/Getty Images]