The Environmental Protection Agency (EPA) tried to play nice when it came to fracking, but Halliburton wasn’t up for it. Now, the company has been subpoenaed.

The EPA has subpoenaed Halliburton for the secret formula for the liquid chemical cocktail it pumps into underground rock structures so natural gas can be accessed through a process known as hydraulic fracturing or fracking. Health concerns have been steadily growing about fracking, and most of the concerns deal with water contamination.

Earlier this year, the EPA asked nine companies to tell them what goes into their chemical mixtures for fracking, and the Wall Street Journal reports that all of the companies complied except Halliburton. It's not exactly a surprise that Halliburton is playing hardball on the fracking issue. The company is the namesake of the “Halliburton loophole,” which exempts natural gas companies from having to disclose their fracking mixtures because of proprietary concerns. Former vice president and former Halliburton CEO Dick Cheney is said to have been instrumental in implementing the loophole.

CBS News is also quoting members of the Halliburton public relations team as saying the EPA’s request was “unreasonable,” and that the agency required the company to disclose more than 50,000 pages of information in a short period of time. “We are disappointed by the EPA's decision today," Halliburton spokesperson Teresa Wong said in a statement. "Halliburton has been working in good faith in an effort to respond to EPA's September 2010 request for information on our hydraulic fracturing operations over a five-year period.”

This clash comes at an interesting time. President Obama has been endorsing more natural gas use in the days following the Democratic party’s dismal performance in the midterm elections. And while fracking has been underway in Pennsylvania, there are still restrictions on the practice in New York. During the election season, fracking was a key sticking point for those who ran for governor there. Now Governor-elect Andrew Cuomo will likely be keeping an eye on the Halliburton situation in neighboring Pennsylvania. Expect many other interests to do the same.

Also on MNN: Is hydraulic fracturing safe? An in-depth explainer

EPA subpoenas Halliburton over fracking
Oil services giant is the only company not to comply with the EPA's request for the ingredients of the company's secret fracking formula.