WASHINGTON (AP) _ Citing concerns by police about potentially cancerous side effects from using traffic radar guns, a senator is urging federal regulatory agencies to investigate whether current safety standards for microwave radiation are adequate.

''We owe it to the dedicated men and women who patrol our streets day and night to aggressively ensure their health and safety,'' Sen. Joseph Lieberman, D-Conn., said Monday as he conducted a hearing into concerns about police radars.

Police officers say they believe radiation from the guns is to blame for cancers found in officers who used them over many years. The officers complained that the government isn't doing enough to warn troopers or to investigate the medical effects.

''Hand-held police radar guns should be restricted or banned,'' said Thomas Malcolm, a police officer in Windsor Locks, Conn., who blames his testicular cancer on using a radar gun for 15 years.

Faced with increasing reports alleging a link between use of radar guns and cancer, Connecticut recently passed a law banning use of hand-held radar guns and requiring that fixed units be mounted outside police cars. Police groups have urged other cities and states to take steps to minimize officers' exposure.

At a hearing before a Senate governmental affairs subcommittee, an official of the federal Centers for Disease Control said that more research is needed but that so far no evidence supports the police officers' claims.

''At present, the experimental and epidemiological evidence do not suggest that the levels of radiation emitted by traffic radar devices can be hazardous,'' said Bryan D. Hardin, Washington director of the National Institute for Occupational Safety and Health, part of the CDC.

But another researcher said there is cause for concern.

Dr. W. Ross Adey, a medical researcher, said industry standards for safe exposure levels are inadequate. He said microwave emissions of the sort emitted by radar guns ''may carry a significant biological and biomedical risk.''

Adey, associate chief of staff for research and development at Pettis Memorial Veterans Medical Center at Loma Linda, Calif., said the standards ''have become a refuge for special interests'' wanting to minimize the potential effects.

Lieberman urged the Food and Drug Administration and the Environmental Protection Agency to ''take a vigorous look'' at the standards. He said the FDA has issued only a recommendation that the radar devices be kept away from the body.

Police unions and concerned officers contend that prolonged exposure to microwave emissions from radar guns inside police cruisers cause various types of cancers, including rare eye and testicle cancers.

They say many officers who used hand-held radar guns routinely placed the guns between their legs while turned on but not in use.

Gary Phillip Poynter, an Ohio state police trooper and head of research for the National Fraternal Order of Police, said he has found 164 police officers with cancer that may be attributable to the radar guns.

Industry officials disputed the link.

''The current allegations of harmful effects to operators of police radar guns have no support other than that which can most accurately be termed coincidence,'' said John Kusek, senior vice president of Kustom Signals Inc., a Lenexa, Kan., manufacturer of radar guns.