SANTA ANA — The owner of an asphalt paving company pleaded guilty Wednesday to illegally transporting and disposing of four tons of asbestos in the largest asbestos dumping case in the nation.

Henry W. Sprague III, 45, owner of Olympic Asphalt in Garden Grove, pleaded guilty after the trial judge told Sprague that he would most likely face a sentence of a year or less in County Jail, instead of a possible four years and four months in state prison, according to the prosecutor.

Although pleased with the guilty plea, Deputy Dist. Atty. Gerald Gordon Johnston said he will "stress to the court our desire for a stiffer penalty" than a year in County Jail for the dumping of the cancer-causing mineral.

Court documents said the potential health impact of the illegal dumping, which was done on a street in Long Beach Harbor, "could have been devastating" to the public.

Sprague pleaded guilty to two counts of unlawful dumping of hazardous materials and one count of unlawful transportation of hazardous materials. He is scheduled to be sentenced by Superior Court Judge John M. Watson on May 1.

Sprague, contacted at his business Wednesday, said he had no comment. His attorney, Paul Meyer, said he "is comfortable with the settlement" because it allows his client to present evidence of mitigating circumstances at the sentencing.

Paul Andrew Garner, 53, of Hemet, a Sprague employee and co-defendant in the case, faces trial on two felony counts of illegally transporting and disposing of hazardous waste.

According to Johnston, Sprague's company allegedly dumped four tons of nearly pure asbestos at 9th Street and Harbor Avenue in Long Beach. The street is owned by the Port of Long Beach. The asbestos was packaged in about 150 paper bags.

Authorities say the incident is the largest illegal dumping of asbestos prosecuted in U.S. history. Once commonly used to insulate homes and other buildings and as a filler for asphalt, asbestos was found to cause cancer in the 1970s and is now strictly regulated by the federal government.

Those businesses that use asbestos can pay to dispose of it in hazardous-waste landfills or other landfills that accept such waste.

The case, according to court records, started with an anonymous tip June 13 to the Garden Grove Police Department. The tipster claimed that Sprague had rented a dumpster into which were thrown large bags of asbestos that had been stored at the Garden Grove company.