The regulations require all TRU engines on the road in California, about 40,000 at any given time, even those travelling from outside the state, to have emission control technology no older than seven years. This can be achieved by the addition of new emission control mechanisms or the purchase of a new engine.

Concern had been raised that the late-in-coming waiver would not be granted and therefore the regulations would not be enforceable.

Once fully implemented in 2020, the regulation will eliminate 2,000 tons of diesel particulate matter emitted into California’s air. Recent research has shown that those who work around diesel engines endure the brunt of the health impacts from this exhaust.

Adopted in February 2004, these regulations are part of the California Air Resources Board (ARB) strategy to reduce particulate matter from diesel engines. Diesel particulate matter was listed as a toxic air contaminant in 1998 triggering a requirement to reduce public exposure. Toxic air contaminant classification are compounds found to cause or contribute to deaths or serious illness, or pose a present or potential hazard to human health. Diesel PM constitutes 70% of the airborne carcinogens in California’s air.