PASADENA, CA --- The ports of Long Beach and Los Angeles are continuing to enforce their clean truck programs while a federal court considers the legality of the programs' requirements. 

The clean truck programs, aimed at reducing air pollution from harbor trucks by more than 80 percent within five years, progressively ban trucks that don't meet 2007 emission standards by 2012. To finance the $2 billion truck replacement program, the ports in October began charging a fee on loaded containers. In January, the ports also began collecting a separate cargo fee. 

Port attorneys this month appeared before the Ninth Circuit Court of Appeals in Pasadena to defend the programs against challenges from national trucking and retail groups, the Daily Breeze newspaper reported. Opponents argued that the programs violate federal law. 

Arguments primarily focused on issues related to the programs' safety and security measures, along with requirements that trucking companies sign concession agreements in order to operate in city-regulated marine terminals, the Daily Breeze reported. A panel of three judges listened to about 30 minutes of testimony on March 4 and agreed to issue a decision within a month. 

"The court could rule either way after today's vigorous arguments, but we hope the outcome reflects support for a sustainable clean trucks plan that protects public health and the environment," Jessica Lass of the Natural Resources Defense Council told the Daily Breeze

Opponents of the L.A. Port plan were particularly critical of provisions requiring that concession trucking companies incrementally hire employee drivers beginning this year. This requirement was added to shift vehicle purchase and maintenance costs from contract drivers to the trucking companies. The Long Beach Port has an alternative plan, which offers subsidies to contract drivers to cover up to 80 percent of new truck costs. 

After the judges render their decision, an appeal is expected -- regardless of which way the judges lean. Experts say the case could very well end up before the U.S. Supreme Court.