Officials with the California Air Resources Board proposed Oct. 1 changes to the state's off-road diesel emissions rule. The proposed changes were made by CARB staff in response to data released by the Associated General Contractors of America showing CARB's off-road rule is not needed to meet diesel emissions targets the board set in 2007.

"In seeking to change both the method and the objectives of this rule, the board's staff is acknowledging that their original rule was as flawed as it was costly," said Mike Kennedy, the association's general counsel. "They have all but rejected the notion that forcing contractors to retrofit construction equipment is a viable strategy for reducing diesel emissions."

Kennedy noted that CARB staff is now recommending a new strategy of requiring contractors and other off-road diesel equipment users to more gradually replace aging construction equipment with newer, more efficient equipment. And while contractors will still receive credits for retrofitting equipment, the amended rule would not force contractors to install the cumbersome filters that do not cut emissions of nitrogen oxide and have raised significant safety and cost concerns.

Board officials also are proposing to delay the off road diesel rule for at least two years, but to set even more aggressive diesel emission targets. "Staff members are crafting targets to justify their rule, instead of crafting rules to meet their targets," Kennedy said. "For an agency where science is supposed to trump all else, the staff seems pretty flexible with its science."

Despite the evolving emission targets, Kennedy said the association and its member contractors were willing to work with the members of CARB to ensure that the final off-road diesel emissions rule protects the state's air quality while preserving what's left of the state's construction jobs.

Kennedy also suggested that any other public officials considering mandates for diesel retrofits take note of California's change of heart. "Retrofit mandates have to be very badly flawed for California's aggressive environmental regulators to say they won't work," Kennedy noted.