A federal appeals court Wednesday ordered the Transportation Security Administration to explain why it hasn't complied with the court's year-old decision demanding the agency hold public hearings concerning the rules and regulations pertaining to the so-called nude body scanners installed in U.S. airport security checkpoints.

The U.S. Circuit Court of Appeals for the District of Columbia Circuit's brief order came in response to the third request by the Electronic Privacy Information Center for the court to enforce its order.

A year ago, the circuit court, in a lawsuit brought by EPIC, set aside a constitutional challenge trying to stop the government from using intrusive body scanners across U.S. airports. But the decision on July 15, 2011 also ordered TSA "to act promptly" and hold public hearings and publicly adopt rules and regulations about the scanners' use, which it has not done.

The public comments and the agency's answers to them are reviewable by a court – which opens up a new avenue for a legal challenge to the 2009 agency decision to deploy the scanners. Critics maintain the scanners, which use radiation to peer through clothes, are threats to Americans' privacy and health, which the TSA denies.

The three-judge appellate court, which is one stop from the Supreme Court, said that the Transportation Security Administration breached federal law in 2009 when it formally adopted the Advanced Imaging Technology scanners as the "primary" method of screening. The judges — while allowing the scanners to be used — said the TSA violated the Administrative Procedures Act for failing to have a 90-day public comment period, and ordered the agency to undertake one.

The appellate court has twice denied motions from EPIC to order the TSA to get going.

But on Wednesday, the three-judge circuit court panel ordered (.pdf) the TSA to respond by August 30. Last month, TSA spokeswoman Lorie Dankers told Wired that hearings – and the agency's response to those hearings – aren't expected until "next year."

Marc Rotenberg, EPIC's executive director, said in an e-mail the "court's order indicates that we have meritorious arguments."

Under the Administrative Procedures Act, agency decisions like the TSA's move toward body scanners must go through what is often termed a "notice and comment" period if their new rules would substantially affect the rights of the public — in this case, air passengers. The Environmental Protection Agency often undertakes "notice and comment" periods for proposed pollution regulations.

But the court did not penalize the TSA for its shortcomings. The TSA argued to the court that a public comment period would thwart the government's ability to respond to "ever-evolving threats."

Day's after the court's decision last year, however, the TSA began moving toward displaying to screener technicians broad, generic outlines of passengers instead of taking virtual nude shots.

Concerns about the machines include the graphicness of the images, the potential health risks and the scanners' effectiveness.

Jim Harper, the director of information policy studies at the Cato Institute, has started a White House petition to force the TSA to promptly follow the law. By government policy, if the petition gets 25,000 signatures, the President Barack Obama administration is obligated to publicly respond. The petition needs another 9,000 signatures as of publication.