The chairman of the House Science, Space, and Technology Committee responded with suspicion to new clean air standards proposed by the EPA, saying they appear to be based on “secret data.”

On Friday, the EPA announced that, in response to a court order, it would recommend that the annual health standard for harmful fine particle pollution be within a range of 13 micrograms per cubic meter to 12 micrograms per cubic meter, instead of the 15 micrograms per cubic meter allowed now. The agency said that 99 percent of U.S. counties are projected to meet the proposed standards without undertaking any further actions to reduce emissions because of recent Clean Air Act rules.

“The proposed changes, which are consistent with the advice from the agency’s independent science advisors, are based on an extensive body of scientific evidence that includes thousands of studies – including many large studies which show negative health impacts at lower levels than previously understood,” the EPA said in a press release. “By proposing a range, the agency will collect input from the public as well as a number of stakeholders, including industry and public health groups, to help determine the most appropriate final standard to protect public health. It is important to note that the proposal has zero effect on the existing daily standard for fine particles or the existing daily standard for coarse particles (PM10), both of which would remain unchanged.”

“While I look forward to reviewing this proposal in more detail, I am concerned that EPA is pursuing yet another costly, job-killing regulation at a time when the American economy can least afford it,” said committee Chairman Ralph C. Hall (R-Texas). “I am also troubled that this rule appears to be based on secret data that EPA has refused to make public despite repeated requests from scientific experts and Members of Congress.”

EPA Administrator Lisa Jackson will testify before Hall’s committee on June 28.

“We are all for clean air, and according to EPA’s own data, particulate matter emissions have plummeted 55 percent in the last decade,” the congressman added. “However, in advancing this regulation, I fear the Obama Administration has failed to make the case that the existing standard is not sufficient or that the underlying science has changed. Rather, the decision appears to further demonstrate EPA’s regulate-at-all-costs mentality.”

The EPA will accept public comment for 63 days after the proposed standards are published in the Federal Register. The agency will also hold public hearings in Sacramento and Philadelphia, and will issue the final standards by December 14.