Christina O'Haver, The Union Democrat

Mother Lode farmers could soon join business owners, school districts and other government agencies in spending tens of thousands of dollars to comply with state regulations that aim to reduce diesel-fuel emissions.

The California Air Resources Board is considering imposing the "In-Use Off-Road Mobile Agricultural Equipment Regulation" to wrap up a series of diesel-emission regulations.

The regulations have gradually been implemented since the board adopted the Diesel Risk Reduction Plan in 2000. The plan was created to comply with federal standards after a scientific review panel declared diesel emissions a toxic contaminant, according to board spokeswoman Karen Caesar.

The Air Resources Board presented the potential regulation to the Tuolumne County Farm Bureau at a meeting earlier this month, as part of a series of public workshops being held throughout the state early this year. About 40 people attended and provided feedback, according to Tuolumne County Agricultural Commissioner Vicki Helmar.

"Generally speaking, what these rules do is they require people to replace their older engines with cleaner engines," Helmar said. "The problem is, these engines could be very, very expensive and (the board) usually provides a timeline."

District supervisors Karl Rodefer and Sherri Brennan, who is a rancher, expressed concerns for Mother Lode farmers.

"I think the requirements are so stringent that they will have … very far-reaching impacts on our agricultural industry and all industries that utilize both motorized and stationary diesel engines," Brennan said.

Rodefer, who attended the meeting, said it would not only require farmers and ranchers to upgrade and purchase new equipment to avoid heavy fines, but it would devalue older vehicles.

He said many ranchers have equipment that is decades old but used too infrequently to cause significant pollution.

Meeting attendees argued similar points, saying the residents in the Sierra foothills do not need the same regulations as in more highly-polluted areas like the Central Valley, Helmar said.

She also said Tuolumne County's air quality has been improving, according to federal ozone standards.

This feedback could possibly contribute to geographic and low-use equipment exemptions in the regulation, Helmar said.

The Air Resources Board plans to complete two rounds of public workshops before proposing the regulation in September. The board is scheduled to hear the proposal in December and decide whether to adopt it.

"This is just starting now," she said. "We're going to have plenty of time to provide our input."

Small businesses and schools have already been feeling the effects of a related regulation that requires privately and federally owned vehicles and buses and privately or publicly owned school buses to either be retrofitted or completely replaced.

Adopted in December 2008, the regulation has varying deadlines depending on a vehicle's type and age, the entity operating, how many other vehicles are in its fleet and other characteristics.

Motorhomes for non-commercial, private use are exempt.

Local school districts were told to make most of their buses compliant by the beginning of this year.

Summerville Union High School District spent $90,000 out-of-pocket to retrofit four buses and replace two that were too old to upgrade, according to Chief Business Official Tonya Midget.

The district would have spent more if it had not qualified for a grant, Midget said. She said new buses cost about $160,000 each.

Calaveras Unified School District received a grant to fund the replacement of five buses, amounting to $125,000 in out-of-pocket costs, according to Superintendent Mark Campbell.

Campbell said the district also retrofitted nine buses without help from the grant. He was not sure how much the retrofitting cost.

Businesses relying on diesel trucks have also taken a hit.

K-V Trucking - a Sonora-based business that hauls sand, gravel and agricultural products - will have to retrofit its small fleet of three trucks, co-owner Vince Esposito said.

Esposito estimated it will cost about $17,000 per truck. One truck must be upgraded by 2014 and the other two by 2016, he said.

"Nobody can afford to do it in today's economy, but they don't seem to be giving us any choice," Esposito said.