18 June 1998

The negotiations between a number of truck engine manufacturers and the U.S Environmental Protection Agency (EPA) on the alleged use of emission-cheating "defeat devices" have now gone public with the announcement that the EPA has sued Mack Trucks Inc. for tampering with pollution control systems on diesel engines used in its trucks. Mack has filed its own suit against EPA, challenging the allegations.

In the suit against Mack, EPA charged the company with selling diesel engines equipped with devices that defeat the engines' emission control systems. EPA said Mack designed computer software so that the diesel engines essentially ran in a non-compliance mode at highway speeds, but that higher emissions levels would not show up in controlled federal tests. EPA's suit asks the court to order Mack to recall and fix engines currently in operation and to take other steps to offset the alleged additional air pollution.

Mack's suit requests federal court protection and declaration that the company has not violated the Clean Air Act. Mack's complaint said the company's engines have passed federal emissions tests, have consistently been certified by EPA, and that the injection timing system now targeted by EPA, has been known to the agency for several years. Mack also said that its engines are not altered in any way after testing and they operate on the road in the same fashion as they do during the federal test. Mack has asked the court to declare that its injection timing system does not constitute an illegal "defeat device", to prohibit EPA from revoking its current certificates of conformity or denying those certificates for the 1999 model year, as well as preventing the agency from seeking or assessing any penalties against Mack.

Source: Diesel Progress