Operators of harbor craft in California (other than fishing boats, which are exempt) have until December 2024 to have all their boats operated with Tier 4 engines outfitted with diesel particulate filters (DPFs), attachments designed to burn particulate matter (soot) before it exits into the atmosphere. The problem is that such DPFs do not exist and cannot be developed by that target date.
California sees itself as a climate leader, and because of its economy’s size, its climate and emissions regulations affect many other states. Other states also copy its climate regulations. The Trump administration had barred California from adopting vehicle emissions rules that conflicted with the federal government’s authority (established in 1975) to set Corporate Average Fuel Economy (CAFE) requirements, but the Biden administration reversed that ban. Under Biden, the Environmental Protection Agency has encouraged California to set stricter-than-federal emission rules and has also encouraged other states to follow California’s rules, essentially surrendering federal pre-emption to the states on this matter.
In its harbor craft DPF rule, the California Air Resources Board (CARB) is allowing climate ideology to trump common sense. Its refusal to discuss any slowdown or mitigation of its rule has now resulted in a conflict with the U.S. Coast Guard, which announced in a February 21 letter that it would not accept or enforce the CARB DPF rule for commercial harbor craft. The technology does not exist for Tier 4 marine engines, and the timeline is insufficient for them to be developed and properly tested by the relevant agencies.
DPFs work by recirculating hot exhaust gases to incinerate soot particles trapped in a filter. They can eliminate up to 99 percent of those particles. DPFs have to operate at high temperatures for full efficiency; soot can build up in the system, requiring periodic burnoffs called regeneration.
CARB began requiring DPFs for trucks in 2007. Early models were made with metallic cores and caused several spectacular truck fires, resulting in multiple lawsuits by truckers and trucking organizations seeking the repeal of the DPF requirement. Later models substituted ceramic cores, which CARB claims are safer, although internal CARB documents still reveal an unacceptable level of safety risk. But apparently CARB learned nothing from its truck DPF experience.
CARB’s stubborn intransigence makes no sense even in terms of its stated goals of reducing emissions. If its harmful DPF regulation is allowed to stand, California harbor operators will simply cease operations and either go out of business or shift their assets to other ports out of state. This will result in severe supply-chain disruptions to California port operations and cost increases to consumers. The irony is that if that happens, it will cause a drastic increase in truck traffic to make up for shortfalls in ship traffic—in other words, a big jump in emissions.
That’s why California Gov. Gavin Newsom needs to listen to marine operators and waive or suspend CARB’s disastrous DPF rule and/or extend its timetable. Allowing the states to get too far ahead of federal regulators creates harmful confusion. Pushing commercial harbor craft off California waters will threaten many livelihoods, hurt consumers, benefit no one and do nothing to actually reduce emissions or advance climate goals.