A Travelers' representative in New Haven, Conn., Marlene Ibsen, said the insurer had not seen legal papers yet and couldn't comment.

The complaint in Los Angeles County Superior Court alleges, among other things, that the insurer and the Los Angeles-based Southern California Insurance Adjusters were negligent in their handling of a toxic mold claim by failing to warn the couple of the danger, and have backed away from promises to fully reimburse the couple.

It charges breach of contract, bad faith, emotional damage, and conduct involving "malice, fraud and oppression."

According to the complaint, after a water leak from a Jacuzzi spread dangerous mold throughout his 8,000-square-foot Cold Water Canyon home, the mold sickened Mr. McMahon and his wife, while Muffin "died from mold-related illness."

In California, where more than 2,000 mold damage claims at the end of last year made the state second only to Texas, Mr. McMahon is not the first notable to lodge a claim. Filing a previous action was Erin Brockovich, the paralegal whose legal crusades against corporate polluters were dramatized in the Oscar-winning movie starring Julia Roberts.

Janine Gibford, personal lines advocate for the Association of California Insurance Companies in Sacramento, said the McMahon suit could accelerate mold issues in California. "Every time you get star power behind an issue, it does pick up speed," she noted.

As to Mr. McMahon and his mold claims, "I don't know whether he'll be the new poster boy or not," she said. "Anything is possible."

An American Insurance Association representative, Nicole Mahrt, said the McMahon suit "just raises the profile of the [mold] issue and makes it more important to develop standards and sound science on this." She noted that California had approved a measure to develop mold abatement standards, which still hasn't been funded.

The suit, filed by attorney Allan Browne, also names several contractors as defendants.