Marge Mollers heaved recycling bins out of knee-deep mounds of snow early Thursday morning, her breath freezing in the subzero air and a layer of frost blanketing her hair.

The job of a Minneapolis recycling worker is especially tough in this Minnesota winter, but it's a far cry from previous years under the multi-sort system of hauling several bins of glass and other recycling to the truck, then dumping them into different compartments.

Under the new single-sort system, fewer workers are being injured lifting bins, falling or getting cut by glass, recycling is up and the city is saving money.

"It's been a great success," said Dave Herberholz, the city's director of solid waste.

Last winter, a dozen recycling workers were injured on the job, compared with just one so far this season. The city has saved more than $250,000 on workers' compensation since implementing the system, and workers say their jobs are easier and safer — though employees agree there are still improvements to be made.

"We're probably not where we'd like to be at," general foreman Sheldon Swensen said at an employee safety meeting Thursday, though he said he thinks they're moving in the right direction.

The program had a long rollout, with the new bins first distributed in November 2012 and all of them in place by July 2013.

Under the new system, workers roll a single cart back to the truck and hook it up to a mechanized arm that dumps out its contents.

That's been a huge improvement from the multi-sort system where workers "had their hands full" carrying bags from curbsides and alleys back to the truck, Herberholz said. Slips and strains — and the resulting knee and shoulder injuries — were common.

They carried the bags to the truck, which had an attached trailer and compartments for each item, and dumped them in by hand.

The truck had space on top for cardboard, making that part of the job one of the most difficult and dangerous. Workers had to toss the cardboard up about 9 feet to the roof, then climb a ladder on the side of the truck and secure the load with a tarp.

"For us short folks, that was a drag," said Mollers, 53, who's been in her job since 1997. One man was injured falling off a truck when a rope snapped as he was attaching the tarp.

With multi-sort recycling, the truck's glass bins filled up quickly, so workers broke bottles to make more space.

Cliff Johnson, 53, said he once broke a champagne bottle and a piece of glass flew back and landed in his arm.

"Now you don't have to worry about any of that stuff," he said.

Volume is up

City data on single-sort recycling, from the number of worker injuries to the total recycling rate, won't be complete until this summer.

Workers said they've noticed a big increase in volume, and so far, the numbers back them up.

With the new single-sort system, Minneapolis' recycling rate in 2013 was 23.3 percent — up from 17.4 percent in 2012, according to Herberholz.

Because the city distributed the last single-sort bins in July, the figures for 2013 include some multi-sort recycling.

"We're looking for it to spike again," he said.

The system isn't perfect, though. One concern is contamination from non-recyclable items — food sometimes ends up on paper and makes it unrecyclable, and Styrofoam and plastic bags that end up in bins have to be taken out.

Tom McMurtrie, solid waste coordinator for the city of Ann Arbor, Mich., said plastic bag recycling has been an issue for the city since its single-sort system was implemented in 2010.

"People feel if they put it in their recycle bin, it'll get recycled, even if it isn't recyclable," he said. "It just makes them feel good, so they put that plastic bag in there."

When plastic bags end up at the sorting site, they catch in the machine and it has to be shut down while workers fish them out.

"It's a … downside," he said.

Working in the winter

At Thursday's early-morning safety meeting, about 20 recycling employees talked about preventing wintertime injuries.

A foreman, Harold Wright, led a discussion about staying safe in the cold.

"You have a higher risk of cold if …?" he asked, waiting for someone to fill in the blank.

"… You work here," a worker joked from the back of the room.

Swensen encouraged workers to wear ice cleats on their routes. Some workers at the meeting asked for more sanding in alleyways.

Mollers said this winter has been particularly difficult, and she can't imagine what it would be like if the multi-sort system were still in place.

But even with the change, she said, winter presents challenges. Climbing over snow banks to get to bins is still a process of "playing mountain goat," she said.

On her Thursday morning route with her husband, Jon, Mollers left official warning notes telling homeowners to shovel out bins buried in snow.

When they came to particularly narrow alleys, the couple navigated with the truck in reverse, edging their way past rows of garages.

"It's still a challenge depending on how they plow," Marge Mollers said.

Some risks for workers remain year-round.

The single-sort trucks compact items in the same way that garbage trucks do. Johnson said workers have to remember to turn their faces away from the truck as a spinning blade moves through, because bits of glass sometimes fly out. Earlier in the week, Mollers said, she found glass in her hair.

And though winter weather is tough, Johnson said, warmer seasons present their own challenges.

"I don't mind the cold and the snow, but the pouring rain …" he said, and shook his head.

Emma Nelson is a University of Minnesota student reporter on assignment for the Star Tribune.