"The most optimistic thing to be said is that we're maybe halfway through the whole thing, and we may be only 20 percent of the way," Carroll told a group of analysts and executives at a seminar held by Tillinghast-Towers Perrin and the Claims Resolution Management Corp. in New York.

At least five major corporate defendants have spent more than $1 billion on asbestos-related claims, and asbestos litigation has infiltrated about 85 percent of the nation's business sectors, Carroll said.

Companies ranging from oilfield services giant Halliburton Co. to media conglomerate Viacom Inc. and paper products maker Georgia-Pacific Corp. are fighting a wave of asbestos-related lawsuits.

While asbestos use was most widespread during the 1960s and 1970s, the number of claims filed annually has jumped sharply from 10,000 to 20,000 per year in the early 1990s to three or four times that amount in recent years.

Over 6,000 U.S. firms, along with many of their subsidiaries, are included on RAND's preliminary list of asbestos defendants. Various studies estimate the insurance industry, now struggling under the weight of asbestos-related claims resolution, could pay out $65 billion or more.

MIRACLE TURNED CURSE

A naturally-occurring mineral that was once dubbed a "miracle" for its strength and fire-resistant properties, asbestos was widely used for construction and manufacturing until scientists determined that inhaling its fibers could lead to respiratory diseases and various types of cancer including mesothelioma.

Still, more than 3,500 products sold in the United States contained asbestos at the time of a 1989 study by the Environmental Protection Agency. And the mineral is still legal today, with no effective requirements for warning labels, Tillinghast consulting actuary Michael Angelina said.

Asbestos-related diseases can take as much as half a century to materialize following exposure, which means victims exposed during America's heaviest period of asbestos usage may still develop related symptoms.

Because of this threat of exposure to a victim's health, "the propensity to sue has clearly increased for the nonmalignants," Angelina said. Plaintiffs' attorneys are seeking new clients using ads in Sunday papers, screenings at workers' unions, and Internet sites.

But the fact that asbestos-related claim filings has doubled expectations does not mean the costs of settling those claims will also double, Angelina said.

RAND's preliminary results showed nearly three-quarters of the asbestos-related claims pending in 2001 covered litigants who show no symptoms, while the frequency of filings for more serious asbestos-related injuries has remained relatively steady.