BALTIMORE — A Maryland doctor filed an $800 million lawsuit against a cell phone maker and a telecommunications company, claiming years of using the wireless devices caused his brain cancer.

Chris Newman, 41, brought the suit against Motorola Inc. and Verizon Communications on Tuesday in Baltimore City Circuit Court.

The Food and Drug Administration has said there is no evidence that radiation from cellular telephones poses a health risk. However, the FDA has also said there is no proof that cell phones are risk-free.

The malignant tumor was discovered in March 1998 behind Newman's right ear. Newman's attorney, Joanne Suder, said her client, a neurologist, used wireless phones at least several times a day between 1992 and 1998.

"Because of the nature of his work he had to be in touch with patients on a minute-to-minute basis," Suder said.

The suit seeks $100 million in compensatory damages and $700 million in punitive damages. Motorola was named as the maker of the phone Newman used and Verizon was formed after service provider Bell Atlantic merged with GTE this year.

Concerns that cellular phones may cause cancer or other health problems have grown over the past few years. In June, the FDA announced a partnership with the phone industry under which about $1 million in studies on the issue would be conducted.

A trade group for the wireless industry introduced a policy last month requiring cell phone makers to disclose information on radiation levels produced by their phones.

More than 90 million American now have cell phones; most began using them in the past five years.

Norman Sandler, a spokesman for Motorola, based in Schaumburg, Ill., said company officials had not seen the lawsuit and could not comment. However, similar lawsuits over the past few years have been withdrawn by the plaintiffs or dismissed by the courts, Sandler said.

"We have maintained for years that such assertions are groundless," Sandler said.