SACRAMENTO, CA --- The California Air Resources Board fined Humboldt Transit Authority $24,000 this month for failure to inspect its diesel truck fleet for smoke emissions during 2007 and 2008.

An ARB investigation concluded that the Humboldt Transit Authority -- consisting of Arcata/Mad River Transit System, Eureka Transit Service and Humboldt/Redwood Transit System -- failed to meet the transit fleet vehicle requirements and didn't inspect all the vehicles in its heavy-duty diesel fleet.

"Diesel emissions are the most common toxic air contaminant in California and are a threat to public health," said ARB Chairman Mary D. Nichols. "Transit authorities must ensure vehicles are properly inspected to provide clean air for passengers and the surrounding region."

The law requires owners of California-registered truck and bus fleets to regularly inspect their vehicles to ensure that their engine emissions meet state air quality standards.

As part of the settlement, Humboldt Transit Authority is required to:

• Guarantee employees responsible for conducting the inspections attend a California community college training class on diesel emissions compliance testing and provide certificates of completion within one year

• Provide documentation to ARB that the inspections are being carried out for the next four years

• Ensure all its on-road heavy-duty diesel engines have their software updated with the latest low-NOx (oxides of nitrogen emissions) programming

• Instruct vehicle operators to comply with the state's idling regulations

• Comply with requirements of the fleet rule for transit agencies

• Ensure that all on-road diesel engines are up to federal emissions standards for the vehicle model year and are properly labeled with an emissions control certification label.