It is considered rare for a Senate committee to hold a hearing on issues related to legislation after the legislation has been approved by the committee. Last May the committee approved the bill creating the fund to be financed by companies targeted by asbestos injury litigation and their insurers.

The committee sources said there is no chance the bill reported out by the committee to the full Senate in June will see floor action this year. But Sen. Specter said he has been promised by Senate Majority Leader William Frist, R-Tenn., that floor action will be held early next year.

Sen. Specter, the bill's primary supporter, has been having difficulty lining up support for his bill from both conservative Republicans and liberal Democrats on his own committee.

The latest hearing is being called because a study in September by an economic consulting firm said the proposed fund would be inundated with claims and become insolvent within three years.

The study by the Bates White consulting firm found the proposed fund would face claims of between $301 billion and $561 billion, as people with lung and other cancers, who historically had not been compensated by asbestos lawsuits, filed claims seeking money from the fund.

A staff official of the American Insurance Association confirmed that the hearing is being held but wouldn't comment beyond saying, "The widely differing conclusions as to the potential cost of settling claims under this legislation has revealed only that projecting settlement costs is an inexact science." The spokesman declined further comment.

Under the legislation, claims would be paid through $140 billion contributed over 27.5 years by defendants and insurers as well as money from existing asbestos trust funds.

The study was unveiled at a "brown bag lunch" convened several months ago by Sen. Judd Gregg, R-N.H.

The insurance industry is divided by the proposal, with a number of large insurers joining large defendants such as Dupont, General Electric and Exxon Mobil in opposing the bill.