The Federal Communications Commission is seeking to study whether it needs better guidelines to protect people from cellphone radiation, a question it hasn’t posed in 15 years.

During that period, mobile devices have become ubiquitous and far more powerful. Today, there are more cellphones than people in the United States. But there has been no definitive study on whether the explosive growth is bad for our health.

Before the FCC can even examine the question, however, the agency must get permission from its five commissioners.

The FCC, which sets limits on radio frequency emissions for devices, played down the significance of the action, saying current rules appear adequate and that the proposal is part of a routine effort to make sure its guidelines are up to date.

“We are confident that, as set, the emissions guidelines for devices pose no risk to consumers,” Tammy Sun, an FCC spokeswoman, said in a statement. The agency said it was uncertain when a vote would take place.

The debate is sure to draw heavy interest. The deep-pocketed wireless industry opposes changes to current federal rules. Health advocates have argued that the government has ignored safety concerns raised by some scientists.

Studies have been split on the matter. Some have indicated that cellphone use poses no risk to humans.

Others have suggested possible harm. In May 2011, a panel of health experts organized by the World Health Organization concluded that the devices are “possibly carcinogenic.”

The WHO panel said particular concern is the use of cellphones by children, who spend more time than ever with the devices pressed against their ears or in their pockets. Their skulls are thinner than those of adults and absorb radio frequencies at higher rates.

A separate February 2011 study by researchers at the National Institutes of Health found that 50 minutes of cellphone use altered activity in the part of the brain closest to where the device antennas were located.

“This review is long overdue and it is impossible to imagine how the FCC will be able to retain its current standards which allow 20 times more radiation to reach the head than the body as a whole [and] do not account for risks to children’s developing brains and smaller bodies,” said Renee Sharp, a senior scientist for the Environmental Working Group.

The FCC's proposed inquiry specifically addresses health considerations for children.

The wireless industry said it welcomes an initial inquiry of radiation limits, saying it is confident that the FCC will find no changes need to be made.

The cellphone industry, which garners about $170 billion a year in revenue, has been fiercely protective of its reputation.

The wireless trade group known as CTIA has sued San Francisco over an ordinance that would require retailers to disclose radiation standards to consumers. It has fought similar measures in Maine and Oregon.

John Walls, a spokesman for CTIA, said the concerns over cellphones have been exaggerated.

“Expert agencies and scientific advisory groups around the world have concluded that cellphones operating within government standards post no health effects and are safe for normal use,” he said.