We already know that a lot of people don't like fracking. They don't want it being done near their homes, and they want better regulation on the process.

Part of the problem has been that there is so much secrecy about the chemicals that oil and gas companies are putting into the earth when they start drilling underground—and that that secrecy is built into the law.

But a coalition of environmental groups is pressing for investigations into whether fracking operations have violated the already-weak Safe Water Drinking Act by injecting diesel fuel into the ground.

From an EWG press release on the call for an investigation:

In February, the House Energy and Commerce Committee disclosed as part of an investigation into hydraulic fracturing that energy companies Halliburton and B.J. Services had used diesel in hydraulic fracturing operations in at least 15 states in 2005, 2006 and 2007. However the companies did not reveal to the committee precisely where these injections occurred.

Yet those two companies, EWG continues, had signed a non-binding memorandum of agreement with the EPA in 2003 saying they would not inject diesel fuel directly into underground drinking water sources during the fracking process.

Colorado landowner Janine Fitzgerald said, "As someone who lives with oil and gas operations in my backyard, I am imploring the EPA to find out whether or not any hydraulic fracturing companies have violated the Safe Drinking Water Act by using diesel fuel, and take action accordingly."

Things could change, if bills that would amend the Safe Drinking Water Act are passed by Congress to allow the EPA to regulate the hydraulic fracturing process and to require disclosure of the chemicals used in the process.

Visit EWG to read the letters that have been sent to the EPA, the fracking companies in question, and to Chairmen Henry A. Waxman and Edward J. Markey.