Citing the weak economy, with many trucks sitting idle during this recession, the trucking industry asked the California Air Resources Board to delay the law since the cost to replace or retrofit a fleet is bank-breaking.
State research shows emissions are already 20 percent lower.
"It makes no sense to saddle the trucking industry with regulations that absolutely assures the collapse of thousands of taxpaying businesses," said Richard Lee with Tim A. Manley Trucking.
The industry also questions whether the board's science that shows 9,400 premature deaths could be prevented with these tougher rules is valid, since one of the researchers lied about his credentials.
The public health community says that may be troubling, but should not underplay the impact pollution has on Californians.
"Lung cancer is the main cancer to have been linked to these diesel emissions," said Peggy Reynolds, American Cancer Society.
The trucking industry's plea wasn't enough to detour the first phase.
"What we are not going to do is back away or back down from the need to make progress on reducing the single most serious cause of health-harming air pollutants in this state," said Mary Nichols, California Air Resources Board chairwoman.
The Board, though, will re-do the science over the next few weeks and may consider giving the trucking industry more flexibility with the bad economy in mind before the second wave of big-rigs must comply.
The delay could also cost the state some big bucks. If the state fails to reach air quality standards mandated by the Environmental Protection Agency by 2014, it could lose billions of dollars in federal highway funding.