FERNDALE - If it's in the garbage, then it's also getting on the paved grounds at Recycling and Disposal Services, a transfer station off Slater Road.

Garbage truck tires roll on pet waste and baby diapers scattered in the trash on the "tipping floor," where the trucks dump their loads. That, in turn, ends up spreading fecal coliform, a state-regulated pollutant, over the pavement.

Even the tires are a source of pollution. As are brake pads, chain-link fences and galvanized roofs, all of which release zinc. When it rains, the heavy metal goes into the stormwater with the bacteria. Zinc is lethally toxic to small organisms and fish.

So it may not be surprising that 17 samples at RDS from 2003 to 2006 exceeded accepted levels of lead, copper, zinc, acid, oil and other measures of unhealthy water. A Puget Sound environmental group took notice and threatened to sue.

As an indication of how much the transfer station has improved, it hosted a tour on Wednesday, March 20, by RE Sources for Sustainable Communities, which counts stormwater pollution among its environmental causes.

"RDS is a clean transfer station. It's not a dump," said Lee First, a RE Sources pollution prevention specialist and the tour guide on that stormy morning.

In what First called "a perfect day to see stormwater," about two dozen people from governments, businesses and even a young family on a field trip saw how the solid-waste facility fixed its water-pollution problem.

RDS receives garbage from households outside Bellingham and sends 75,000 tons of trash every year to a landfill in Eastern Washington. Ten to 15 percent of that waste is recyclable, and one building at RDS is devoted to a "pick line," where employees sort metal, wood, wire and cardboard out of the mounds of refuse left by the garbage trucks.

With its commitment to recycling, RDS promotes itself as environmentally friendly. The stormwater upgrades are part of the same philosophy.

"We have to be environmentally harmonious because that's what we do," RDS owner Larry McCarter said. "We're in charge of taking people's waste and being responsible."

Stormwater is the No. 1 cause of urban water pollution, according to the state Department of Ecology, the agency that oversees the permits.

At 61 pages, a stormwater permit isn't something to frame and hang on the office wall like a business license. The permit is complicated, and some businesses don't make stormwater management a priority, said David Westerlund, a consultant with Whatcom Environmental Services. In the previous decade, RDS wasn't keeping up with the latest methods for reducing stormwater pollution. It also failed to file some reports.

Puget Soundkeeper Alliance threatened to sue RDS in 2009 for stormwater violations. The transfer station drains into Silver Creek, which is on a state list of polluted water bodies.

"We didn't really realize the impacts we were having," McCarter said.

The company has invested about $70,000 so far in equipment and ongoing maintenance to upgrade its stormwater controls, RDS General Manager Pete Edwards said.

The easiest and cheapest solution is often "upstream," or closer to the source, Westerlund said. RDS hired him after receiving the legal threat.

RDS stopped parking heavy equipment outdoors, where oil leaks could spread in the rain. It hired a street sweeper to clean the pavement four nights a week. It installed catch-basin filters made of a material that absorbs zinc. The company purchased a vacuum truck to keep the filters clear.

Absorbent pads are dropped into catch basins and pipes to capture oil and grease. Near the end of the stormwater line is a sand filter, and Edwards adds crushed oyster shells to it because they absorb metals and reduce acidity.

Edwards was especially impressed by the grasses planted at the end of the drainage area, where the water samples are taken. He called them "magic." They are the final defense in a long line of controls that have made RDS stormwater compliant.

Reach Ralph Schwartz at 360-715-2289 or ralph.schwartz@bellinghamherald.com. Read his politics blog at blogs.bellinghamherald.com/politics or follow him on Twitter at @bhamheraldpolitics.