Radio listeners in 15 states in recent weeks have heard a broadcast appeal from former House Majority Leader Dick Armey (R-Texas) asking them to help scuttle a bill designed to contain asbestos litigation.

“Hi, I’m Dick Armey and I’m fighting for lower taxes as chairman of the group FreedomWorks,” Armey says in the radio ads. He then tells listeners that the bill backed by Sen. Arlen Specter (R-Pa.) would levy $140 billion in new taxes to create a federal trust fund for asbestos-related disease victims.

Calling the bill an “outrageous idea,” Armey encourages listeners to contact their Senators and urge them to stop it.

But at no time in the ad — made in his capacity as co-chairman of FreedomWorks, a conservative grass-roots network — does Armey disclose that he is also working as a lobbyist for Equitas, a British insurer that has lobbied to thwart the asbestos trust fund legislation.

Armey’s work on behalf of Equitas comes at a time when FreedomWorks — the successor to the groups formerly known as Citizens for a Sound Economy and Empower America — has made opposing the asbestos legislation a top priority. In addition to paying for a radio and print ad campaign, the group is also tapping its networks of activists to help, a move it claims is generating hundreds of calls and thousands of e-mails to Senate offices.

FreedomWorks, whose platform is devoted to promoting conservative economic principles, is organized as a 501(c)(4), a tax-exempt status that does not require the group to list its donors.

Chris Kinnan, a spokesman for the group, declined to say whether Equitas has contributed.

“It’s pretty clear what our mission is,” he said. “So the groups who support us support that, too.”

In a statement, Armey said his work on the issue is consistent with his longstanding views on the subject.

“Throughout my entire political career I have favored tort reform to fix our broken legal system, and the asbestos litigation crisis is one of the saddest examples of the way trial lawyers have broken our court system, costing jobs and providing little relief for actual victims,” he said. “When it comes to tort reform — and the rest of the FreedomWorks’ agenda of tax reform and Social Security reform — it’s very clear where I stand and where FreedomWorks and its members stand.”

Armey did not address his work for Equitas on behalf of DLA Piper Rudnick Gray Cary, and lobbyists at the firm could not be reached for comment.

FreedomWorks spokesman Kinnan said Armey’s work for Equitas is “not even something we’re equipped to disclose.”

“To be honest, I didn’t even know he was registered” to lobby for Equitas, Kinnan said.

But some watchdogs said it was inappropriate for Armey not to disclose his dual roles.

“When corporate interests are essentially hiring grass-roots organizers at FreedomWorks, that should be revealed,” said John Stauber, executive director of the Center for Media and Democracy, a nonpartisan organization that tracks public relations campaigns. “There’s never been a requirement to report grass-roots lobbying in this country, and it allows the special interests who fund FreedomWorks to hide behind that loophole in the lobby law.”

Equitas, a British insurance company, won a key concession in the asbestos bill last week when Specter agreed to an amendment that would grant the company the same relief as American insurers in the event that they have trouble meeting their obligations to the trust fund.

In previous weeks, though, Equitas’ Washington representatives spoke out against the bill, calling it unfair.

In January testimony before the Judiciary committee, Jeffrey Robinson, a lawyer for the company, railed against the provision that the recent amendment addresses.

He also called bill’s method for determining insurance contributions into the trust fund “patently unacceptable.” And he criticized a provision in the bill that allows certain insurers, but not Equitas, to make side agreements about payments into the trust fund.

“Absent steps to address these identified failings in the Asbestos Insurers Commission,” Robinson told the committee, “this legislation will be neither effective nor fair.”

Meanwhile, Senate filings show that Armey, as a lobbyist for the firm DLA Piper, has been working on the Equitas account.

The client has been a big moneymaker for the firm. Equitas directed $920,000 of the $1.7 million it spent on outside lobbying help last year to DLA Piper.

And the company has continued to hire heavy-hitting lobbyists to work the issue. Last month it retained Quinn Gillespie and Associates, the firm co-founded by former Republican National Committee chairman and onetime Armey aide Ed Gillespie.

Kinnan said FreedomWorks’ agenda is determined in part by which issues are attracting attention in Congress. Focusing on asbestos legislation, he said, was a natural continuation of FreedomWorks’ campaign to reform the judiciary.

“Our members have been surprisingly articulate and energetic about this,” he said. “They understand the nuances of the debate, and they’ve been unusually active.”

Armey retired from the House in 2002 after serving nine terms. Last year, he joined both DLA Piper and FreedomWorks, which he co-chairs along with former White House counsel C. Boyden Gray and former Sen. Jack Kemp (R-N.Y.).