When you order a product from overseas, there’s a good chance it’s shipped through a port in southern California.

Up to 40% of the goods imported to the U.S. arrive there and pass through big distribution centers in the region.

But as the number of warehouses has grown, so has the truck traffic. Heavy-duty diesel trucks emit carbon pollution and toxic air pollutants.

“These trucks that go in and out of these communities and these warehouses cause what we call ‘diesel death zones,’” says Faraz Rizvi of the California-based Center for Community Action and Environmental Justice.

He says the pollution has dire consequences. People living near the warehouses have higher rates of asthma and cardiovascular disease.

So local groups have been pushing for change. In a recent win, the South Coast Air Quality Management District adopted a new rule. It requires warehouses to cut their pollution – for example, by using zero-emission trucks – or start paying fees. 

Some industry advocates argue that compliance will be expensive, and companies might cut jobs.

But Rizvi and others consider it an important victory.

“What we really need is for the industry to pay up and make sure that they’re investing in green technology,” he says.

Reporting credit: Stephanie Manuzak/ChavoBart Digital Media and Molly Matthews Multedo