Pass through the Salinas Valley on a fall afternoon, and you’ll see signs of a healthy ag economy: harvest crews traversing lettuce fields, fumigators prepping with tarps, and refrigerated produce rigs barreling down the roads. 


Despite some 5,000 trucks operating in the region on any given day, the air quality is generally good, thanks in large part to Monterey Bay breezes. And the refrigerated trailers that haul perishables don’t tend to idle overnight. 


Local truckers are working to comply with 2008 diesel rules issued by the California Air Resources Board, requiring fleets to update their oldest diesel engines on a phased schedule. By 2023 the oldest on the road will be from 2010. 


They also face a separate set of rules requiring similar updates for their “reefer” trailers every seven years. With a public comment deadline approaching Oct. 19, the ag industry is fighting to make sure haulers, rather than growers, are responsible for reefer compliance. 


Sonny Tut, owner of Destiny Transportation in Watsonville, says he’s seen the ARB tighten its rules over the 35 years he’s been in business, but this requirement to scrap his entire fleet is the most significant change. “This is the worst; this is the most expensive,” he says. 


As truckers start updating their fleets to new tractors, which cost in the low six figures, some are opting out entirely. 


“We employ guys that are ex owner-operators,” says Jeff Cordova, vice president of Brent Redmond Transportation in Hollister. “Truck operators sell their equipment, and come to us as drivers.” 


Though businesses say the rules are particularly onerous, Richard Stedman, director of the Monterey Bay Unified Air Pollution Control District, says newer and more efficient engines save on fuel costs.


“I think we’ll look back and say this was the logical thing to do,” he says. “Unfortunately, it’s being driven by air-quality concerns. It should be driven by economic concerns.”


The public health case for updating old fleets is strong. Short-term, diesel particulates exacerbate asthma and other respiratory conditions, while long-term it’s been linked to pulmonary disease and cancer.


The air district recently finished replacing a dozen old irrigation pump engines on eight farms. Growers paid about $2,000 for the $12,000 engines, thanks to air district grants and a deal from manufacturer Caterpillar. 


“We’ll reduce in the order of tons of nitrous oxides with the replacement of these pumps,” Stedman says.