Waste Management has added six compressed natural gas refuse trucks to its fleet in Chico, Calif., as the refuse hauler continued to aggressively pursue its sustainability goals.

Earlier this month, Waste Management of North Valley rolled out the six medium-duty, dedicated CNG trucks that reduce particulate matter by 90 percent and greenhouse gas emissions by 25 percent, according to the company.

"We see an average annual reduction of 22 metric tons of greenhouse gases and 8,000 gallons of diesel with the CNG trucks," said Ryan West, district manager. "We are proud to be the first and only waste and recycling collection company in the area to operate the CNG trucks, which helps keep the air in our community clean."

Waste Management's Chico fleet is made up of Class 7 trucks with ASL refuse bodies and powered by Cummins ISLG CNG engines that generate 320 horsepower. The hauler operates 14 trucks, including the six CNG trucks.

The new trucks will use the PG&E fueling station in Chico.

The company has also implemented route optimization software that reduces driving time by several thousand hours each year. In addition, the truck engines are programmed to shut down automatically after idling for five minutes to save fuel and further reduce emissions.

The nation's largest refuse hauler began adding natural gas vehicles in the early 1990s and in four years ending in 2011 increased fuel efficiency and reduced emissions by 20 percent.