Since he first testified before Congress a year ago, bulk e-mailer Ronald Scelson has been driven literally underground.

Scelson, who calls himself a former spammer who is now "100 percent legal," told a Senate panel yesterday he moved his operations from his house in a New Orleans suburb to an old, unused nuclear fallout bunker that he leased from the federal government.

But Scelson said the move had nothing to do with a five-month-old anti-spam law that the Senate Commerce, Science and Transportation Committee is evaluating. Instead, he said his testimony last year led to harassment and threats from anti-spam vigilantes.

Now, he said in an interview, he continues to send out between 20 million and 30 million commercial e-mails every day that comply with the CAN-SPAM law enacted late last year to curb unwanted messages.

While that is down from roughly 120 million a day Scelson sent out a year ago, several witnesses told the senators that spam overall not only continues unabated, but has grown since the law took effect.

Shinya Akamine, chief executive of Postini Inc., a spam-filtering company that handles 1.5 billion pieces of e-mail a week for businesses, said spam has grown from about 78 percent of all e-mail traffic to 83 percent this year. Other industry estimates place the figure in the 60 percent range, but rising.

Nonetheless, Akamine and other industry and law enforcement officials praised the new law and said it needs time to work.

"CAN-SPAM was the right bill at the right time for all the right reasons," said Ted Leonsis, vice chairman of America Online. "We look forward to measuring its success with more time."

Among its provisions, the law makes it a crime to falsify the originating address of a piece of e-mail, requires labeling for pornography, and mandates that bulk mailers honor requests to be removed from mailing lists.

Timothy J. Muris, chairman of the Federal Trade Commission, said his agency has pursued 62 cases, many of which began before the new law took effect. Asked by committee Chairman John McCain (R-Ariz.) why more cases weren't brought against the businesses that use spammers to market their products, as the new law allows, Muris said the FTC also has filed cases against those businesses.

Jana D. Monroe, assistant director of the FBI's cyber crime division, said the new law allows criminal prosecution of spammers because it makes their activity a crime rather than forcing the government to go after them as facilitators of fraud.

Monroe said the agency is relying on expertise from the Direct Marketing Association -- which represents bulk marketing firms whose messages often are drowned out by illegal spam or trapped by spam filters -- to help develop cases against roughly 50 targeted spammers. No charges have yet been filed.

But James Guest, president of Consumers Union, said the law has proved ineffective and needs to be changed. He said it places too much burden on users to "opt-out" of getting e-mail, especially since many spammers are using fake opt-out mechanisms to get past spam filters.

Guest said that Congress has given consumers rights to give a blanket no to solicitors at their door, to junk faxes and to telemarketing calls at their homes. They should have the same right to be free of commercial e-mail if they don't ask for it, Guest said.

The CAN-SPAM act directs the FTC to examine a do-not-spam list that would operate in similar fashion to the popular do-not-call list for telemarketers.

Muris said a staff report is awaiting review by the full commission. In the past, Muris expressed skepticism about the idea, and industry strongly opposes it.

But Consumers Union supports giving it strong consideration, according to Chris Murray, the group's legislative analyst.

So does Scelson, who said there would be ways to encrypt the list to prevent the names from falling into the hands of spammers.

He complained that Internet providers such as AOL are blocking his mail even though he claims to be complying with the new law. Most Internet providers impose their own service restrictions that go beyond the law.

As the hearing closed, McCain apologized to Scelson for being forced to uproot his business because of his previous testimony.

Sen. Conrad Burns (R-Mont.), one of CAN-SPAM's chief sponsors, suggested that Scelson's expertise might make him a candidate for employment at either the FBI or AOL.

Leonsis rejected the idea: "We're fully staffed for right now," he said.

Ronald Scelson of Louisiana, a self-proclaimed former spammer, told a Senate panel he is "100 percent legal" but moved his business because of reaction to his testimony last year.