(CN) - The D.C. Circuit dismissed a trucking association's claim that the government has given California too much leeway to set emissions standards that exceed federal limits.
The American Trucking Associations disputed a 2004 rule establishing new standards for "non-road" engines, a category that includes refrigeration units for trucks transporting frozen or perishable goods.
The standards sought to reduce diesel particle emissions 75 percent by 2010, and were phased in by model year. The rule applied to engines based in and operating out of California.
The Environmental Protection Agency approved the standards in 2005. A congressional waiver allows California, due to "compelling and extraordinary conditions," to implement emissions standards that are stricter than federal limits.
Truckers claimed that the EPA inadequately explained the "extraordinary" conditions in California justifying the rule and that the agency did not consider the full costs of implementation.
The trucking association also claimed that the California rule amounted to a national regulation, as many trucks pass through California and will be subject to the rule.
The federal appeals court in Washington, D.C., rejected this argument as "weak," because the rule applies only in California.
Geographic and climatic conditions unique to the state, combined with high population and vehicle use, have led to "well-known" pollution problems there, the ruling states.
The EPA also adequately considered the costs of the rule, estimated at $2,000 to $5,000 per unit, the court determined.
The agency's conclusion that the rule complied with federal law "was reasonable and reasonably explained," Judge Brett Kavanaugh wrote.
The D.C. Circuit denied the truckers' petition for review.
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