Standing in his front yard in Wilmington, Jose Ulloa can’t get a sentence out without coughing. Heavy-duty trucks, headed to and from the Port of Los Angeles, pass in front of his home all day, their engines roaring and their exhaust spewing into the air.

Ulloa, who was diagnosed with asthma a few years ago, suffers frequent breathing problems and was hospitalized after one attack. The truck traffic is likely a trigger, since health officials say diesel exhaust is known to cause asthma attacks and other respiratory problems, including lung cancer.

The parade of big rigs in his neighborhood started four years ago, after a series of traffic pattern changes altered their route.

Imelda, his wife, sweeps the yard and cleans the home nonstop, but black dust still collects on every surface of their home within hours.

“If you blow your nose, black dust will come out,” she said. “It’s a terrible life living here.”

In Oakland, Mashhoor Alammari, who runs a small fleet of drayage trucks that haul cargo to and from the port, wants to do his part to help clean the air of dangerous diesel exhaust.

His company, The Crew Transportation, Inc., bought two new zero-emission big rigs at a cost of more than $900,000. But the trucks, powered by hydrogen fuel cells, are expensive to operate and there are few if any fueling stations along their routes. The new trucks have been sitting in the parking lot most of the time since he bought them.

“I don’t want to put myself into a financial hole,” he said.

The experiences of the Wilmington family and the Oakland truck company illustrate the frustrations and obstacles that Californians face as state officials pursue an aggressive and controversial mandate to clean the air by phasing out diesel-powered big rigs and other trucks.

California’s mandate, approved by the Air Resources Board last year, is the first in the world to ban new diesel trucks and require a switch to zero-emission vehicles, which are powered by electricity or hydrogen.

Companies face varying deadlines for ending their use of diesel, which for decades has been an efficient powerhouse fueling the economy and transport of goods. Starting in 2036, no new fossil-fueled medium-duty and heavy-duty trucks can be sold in California, and by 2042, large companies must convert their trucks to zero-emission models.

The trucking industry says the regulation is unreasonable and will wreak havoc on the economy, making it difficult to make long-haul shipments. The California Trucking Association and a collective of 17 states, including Nebraska, Alabama and New Mexico, have sued the state, alleging the rule oversteps state power.

From big rigs to garbage trucks and delivery vans, the rules will dramatically change the 1.8 million commercial trucks driven on California’s roads over the next two decades. Sales already are accelerating even though no deadlines have kicked in yet. Last year, one out of every six trucks sold in the state — more than 18,000 — were zero emissions.

California’s mandate is in flux because the state still needs a waiver from the U.S. Environmental Protection Agency before it can start enforcing them. President-elect Donald Trump has criticized California’s electric car mandates and in the past tried to revoke the state’s authority to set its own vehicle standards.

One deadline already has passed: All new drayage trucks, which are used to haul containers from ports, were supposed to be zero emissions by last October. But that deadline is not yet being enforced.

Truck companies like Alammari’s that took a risk to be early adopters of clean trucks are now in limbo, swallowing high operating costs and competing with cheaper diesel-only companies in an already struggling industry.

In the meantime, California’s most vulnerable residents who live near roads with heavy diesel truck traffic may have to wait longer for a solution.

The dangers of diesel

Diesel trucks are among the state’s biggest sources of microscopic particles of soot, which can damage lungs and trigger asthma attacks and heart attacks. They also play an outsized role in California’s smog: While they make up just 6% of all vehicles on California’s roads, they are responsible for 72% of nitrogen oxides, a key ingredient of smog, emitted by on-road vehicles, according to the air board.

In addition, health officials declared diesel exhaust, which contains dozens of toxic gases, a human carcinogen several decades ago because of studies linking it to lung cancer.

In the Los Angeles basin, diesel exhaust is responsible for more than two-thirds of the cancer risk posed by air pollution, according to a risk analysis by the South Coast Air Quality Management District.

The biggest dangers from diesels are in communities near high-traffic corridors. People near the ports of Los Angeles and Long Beach, downtown Los Angeles and parts of the Inland Empire are at risk of 350 to 500 cancer cases per million people because of diesel fumes, according to the analysis. That risk has dropped substantially in recent years as trucks get cleaner.

California’s clean truck rule is expected through 2050 to save $26.5 billion in statewide health costs and save fleet owners $48 billion through reduced fuel and maintenance costs, according to the air board.

“The health benefits from eliminating the pollution (from diesel trucks) far exceed any cost the industry will bear,” said Adrian Martinez, an attorney for environmental group Earthjustice. “Trucking lobbyists and other folks are super loud and they’re going to focus on the difficulties of the transition. But millions of Californians affected by pollution from the freight industry is not acceptable.”

Lots of obstacles for emissions-free trucking

But a lack of fast, reliable charging stations and the vehicles’ limited ranges makes it difficult, even impossible, for trucks to transport goods long distances.

Electric heavy-duty trucks have ranges up to 250 miles, while hydrogen-powered ones can drive about 500 miles on a full tank. They can use the same public fast chargers as cars, but that’s impractical because they take up too much space and charging can take up to six hours. For hydrogen, only 22 fueling stations for large trucks are operating or in development statewide, according to the California Energy Commission.

Battery-powered trucks also are heavy, which means they can carry less cargo. As a result, companies have to charge more, which shippers aren’t usually willing to pay.

The industry also points to the substantial investment that is needed to expand the electric grid’s capacity to eventually charge thousands of battery-powered trucks.

“No one’s opposed” to cleaner air, said Matt Schrap head of the Harbor Trucking Association, which represents drayage truck companies. “It is about practical application and implementation of these rules. We have nowhere near enough infrastructure.”

The air board’s mandate “is the epitome of ready, fire, aim,” he said.

Air board officials stress that truck companies have time and flexible options to comply, and the state is working to help them understand and comply with the complex rules.

“People are worried, I get it. But (the deadline) is not tomorrow,” said Bruce Tuter, who oversees compliance and outreach at the air board. “Charging times, charging speeds, all of that needs to start building up where it gets quicker to charge a truck and where it’s more accessible to charge when you’re traveling long distances.”

Alammari, the truck company owner from Oakland, said he bought his two hydrogen trucks because he had interest from a shipping company that wanted to work with zero-emission vehicles. The profits Alammari would have made working with that company would have justified the added costs of operating a hydrogen fuel cell truck, he said.

At the last minute, however, the company chose to work with someone else. Without any customers willing to pay more to ship with his hydrogen trucks, he can’t use them. He’s doing his best to transition his entire fleet to zero-emission vehicles. He had even ordered three more.

But even with help from state grants, Alammari said it’s not enough to help him operate the zero-emission vehicles or buy more of them. He pays substantially more for insuring them, and it costs twice as much to fully fuel them with hydrogen compared to a diesel, he said.

Without companies willing to ship goods with zero-emission vehicles, early adopters of the technology, like his company, The Crew Transportation, Inc., are at a disadvantage until the mandate makes everyone comply.

“If I don’t get customers to use these trucks, The Crew Transportation is not going to move forward to get the three remaining hydrogen trucks we ordered,” he said.

Air board officials created the most stringent deadlines for drayage trucks partly because they travel near the most vulnerable communities — the low-income communities of color around the ports. They also tend to make shorter trips compared to other heavy-duty trucks, and ports are equipped with some fueling and charging stations, air board officials said.

Some companies that operate drayage trucks near disadvantaged communities may qualify for state grants of up to $336,000 toward the cost of a new hydrogen or electric truck. Under the regulation, they are able to keep their diesel trucks until they reach 800,000 miles or 18 years, whichever is earlier.

But, based on how many miles are already on his trucks, Alammari expects them to be unusable by 2028 under the mandate. As he sees it, the future of the company he’s worked so hard to build is at risk.

In the Los Angeles area, Sandra Espinioza, a truck driver for IMC Logistics, drives seven miles between Lomita and Torrance several times a day before powering up at the WattEV charging station in Long Beach. It’s a short and easy work route that makes it easy for a battery-powered truck.

“They’re really quiet, and a really smooth drive,” she said. “You don’t smell the fumes. When it’s (charged) 100%, you’re gonna be able to go through your day.”

Most of the state’s truck fleets are considered “high priority” — federal fleets, such as the post office, and companies with at least one vehicle in California and $50 million or more in gross annual revenue or 50 or more vehicles.

These large operators have two ways to comply. Most are choosing a phase-in option. Under that option, smaller vehicles, such as UPS or Amazon delivery vans and box trucks, must be 100% zero emissions by 2035. But long-distance, heavy-duty trucks get more time to comply: 10% must be zero emissions by 2030 and 100% by 2042.

This story was originally published by CalMatters and distributed through a partnership with The Associated Press.