The former owner of an asbestos testing laboratory was sentenced Thursday to 26 months in federal prison for his role in one of the largest asbestos scams in U.S. history.

Timothy Carroll was 38 when he pleaded guilty in September 2000 to conspiring with a large asbestos-removal firm to falsify air test results to hide the fact that the removal firm was not cleaning properly.

Carroll admitted he falsified air sample results and destroyed documents that revealed the illegal relationship between Analytical Laboratories of Albany, which Carroll owned, and AAR Contractors Inc. of Latham. Charges included mail fraud, federal Clean Air Act violations and filing false income tax returns.

Four of Carroll's employees also pleaded guilty in 2000 to similar charges. His company was sold in 1999.

Carroll, who is currently free but must report to prison Jan. 16, also received two years of supervised release after prison and 200 hours of community service.

According to court officials, Carroll apologized for his role in the scam during the short hearing in U.S. District Court in Albany. He was sentenced by Judge Lawrence Kahn.

A year-long investigation in 1999 culminated in the arrest of 12 people. In 2004, Alex Salvagno of Loudonville was sentenced to 25 years in prison. His father, Raul Salvagno, received 19 years -- the stiffest penalties handed down for environmental crimes, according to the U.S. attorney. The two ran AAR Contractors.

The Salvagnos were found guilty of racketeering and conspiracy to violate environmental laws for rushing asbestos-abatement jobs at 1,555 buildings, most of them in the Capital Region, over a 10-year period.

During the five-month trial, former employees testified the Salvagnos ordered them to crudely rip asbestos from buildings and falsify up to 75,000 laboratory samples. By working without even minimal safety precautions, the Salvagnos saved on labor costs. The scheme worked for so long because of the Salvagno-Carroll connection.

When the U.S. Environmental Protection Agency began investigating, agents discovered everything from asbestos fibers to chunks of asbestos left behind at job sites where AAR Contractors had performed work. In one case, investigators found asbestos dust on a box of lollipops given out at a bank, according to prosecutors.