WASHINGTON - The Environmental Protection Agency subpoenaed energy giant Halliburton Tuesday, seeking a description of the chemical components used in a drilling technique called hydraulic fracturing.

The EPA said it issued the subpoena after Texas-based Halliburton refused to voluntarily disclose the chemicals used in the controversial drilling practice, also known as “fracking.” Halliburton was the only one of nine major energy companies that refused the EPA’s request.

The agency said the information is important to its study of fracking, in which crews inject millions of gallons of water, mixed with sand and chemicals underground to force open channels in sand and rock formations so oil and natural gas will flow.

The EPA is studying whether the practice affects drinking water and public health.

A Halliburton spokeswoman said the company was disappointed by the EPA’s action.

“Halliburton welcomes any federal court’s examination of our good-faith efforts with the EPA to date,” said spokeswoman Teresa Wong.

Wong said the agency’s request, made in September, was overly broad and could require the company to prepare about 50,000 spreadsheets.

“We have met with the agency and had several additional discussions with EPA personnel in order to help narrow the focus of their unreasonable demands so that we could provide the agency what it needs to complete its study of hydraulic fracturing,” Wong said. Halliburton turned over nearly 5,000 pages of documents last week, she said.