The insulation was used in millions of homes and businesses nationwide. Testing of Zonolite brand insulation, along with Grace internal documents, "reveals that even minimal handling by workers or residents" exposes them to danger from asbestos, Dr. Hugh Sloan, an assistant U.S. surgeon general, wrote in a memo last week. His memo was a request for help from other federal health experts, the Seattle Post-Intelligencer reported Monday.

Only two officials of Grace, based in Columbia, Md., could comment on the memorandum and both were out of town Monday, company receptionists said. Recent studies show even casual handling of the insulation can expose workers or homeowners to 150 times the asbestos level considered safe under federal regulations, Sloan wrote in a memo to Linda Rosenstock, director of the National Institute of Occupational Safety and Health.

Vermiculite from Grace's mine at Libby, Mont., was sold for use in garden products, fireproofing, cement mixtures and more than a dozen other consumer products. The bulk of the ore was heated until it expanded like popcorn, then marketed as Zonolite insulation.

Asbestos, linked to lung cancer and other diseases, is a natural contaminant of vermiculite ore. The Post-Intelligencer report involved vermiculite specifically from the Libby mine, which Grace operated from 1963 to 1990. Estimates of homes containing Zonolite insulation range from 2.5 million to 16 million nationwide, the newspaper said.

The New York Times reported last month that the Environmental Protection Agency was investigating why officials ignored for 18 years a study that showed Grace was using ore laden with asbestos in insulation and other building products.

The Post-Intelligencer said it had obtained internal documents showing Grace officials were aware of health risks from asbestos in insulation in the 1970s. "We believe that a decision to affix asbestos warning labels to our products would result in substantial sales losses," executive vice president E.S. Wood wrote on May 24, 1977, the newspaper reported. "The risk of liability to customers is heightened by the decision not to label our products." Federal investigators are conducting medical tests in the Libby area following reports that hundreds of vermiculite miners and their relatives have died or are dying from asbestos-related diseases. Several lawsuits have been filed on behalf of workers and their families.

On Friday, Grace issued a statement acknowledging that some products made in the 1970s and '80s contained "minute quantities of naturally occurring asbestos." The statement did not mention insulation.

Melanie A. Stone, MPH

Epidemiologist

Scientific Evidence, Inc.