– Minnesota’s indoor skating rinks have a big problem looming under their ice.

Roughly 120 arenas that dot the state and are as cherished as parks in the cities and towns that own them still rely on the chemical Freon to chill their frozen floors.

Once a ubiquitous, inexpensive refrigerant, Freon has for years been known to pose a danger to the Earth’s ozone layer. The Environmental Protection Agency has said that by 2020, the chemical, also known as refrigerant R-22, can no longer be produced or imported.

That’s keeping local rink operators like Zac Dockter in Cottage Grove up at night with two worries: What if my old rinks start seeping Freon? And how is my city going to front $2 million to retrofit the rink from Freon to something more environmentally sound, like ammonia?

U.S. Sen. Amy Klobuchar, D-Minn., has urged EPA officials to be more transparent over how they will shrink the Freon supply — and when exactly it will be taken off the market — so rink owners can ­prepare.

“Not every EPA employee may be thinking about ice rinks,” Klobuchar said. “I think they have to treat it with a sense of urgency. They may not realize how much it would mean for an ice rink in a local community to have to sink a million dollars in without much notice.”

Already the cost of Freon is spiking. Once a buck or two a pound, Freon now runs between $11 and $16 a pound. Beneath Dockter’s two 1970s-era rinks run more than 6,500 pounds of the stuff.

“You’re sweating every day,” said Dockter, director of the Cottage Grove’s Parks and Recreation department. “You think, ‘Oh my gosh, if I get a leak on a Friday night, I could lose hundreds of thousands of dollars. It’s a scary thought. … You’re in fear of keeping your liquid gold.”

If a catastrophic leak occurred and Docktor’s 6,500 pounds of Freon seeped out into the atmosphere, it could punch a hole in the ozone for more than a decade and prove a budget-buster for the city. The chlorofluorocarbon mix is colorless, odorless, nonflammable and noncorrosive, but still has been found to eat away at the protective ozone.

450,000 pounds of Freon

All of the 120 rinks in Minnesota that still use Freon — about 450,000 pounds total — will need to convert in the next five or six years. About a third will require a wholesale upgrade that could cost up to $2 million each.

Nearly all ice rinks in Minnesota are owned and operated by local governments, potentially burdening them with costly improvements.

“We want to keep arenas accessible to people all over the state,” said John Evans of Golden Valley, a hockey advocate and member of the Minnesota Amateur Sports Commission. “Because of the economics and because the towns are subsidizing access, there isn’t money for capital improvements. Then a federal mandate comes and they have to change the refrigerant. … We just want to make sure there is local access for Minnesotans.”

Politicians are trying to help.

Minnesota lawmakers are probing ways to give small communities matching funds using state bond money to upgrade ice arenas. Gov. Mark Dayton’s office said the governor — a former college hockey player — has not yet taken a position on using state money for that purpose.

“The communities can’t just cut this on their own, you know,” said Sen. Jim Metzen, DFL-South St. Paul, who is leading the effort this year. “It’s the right thing to do. They have to jackhammer the floors up and redo them. I think it’s a good use of money.”

The EPA says it supports “smooth transitions” and has a long-standing policy in ozone protection regulations that allows rinks to use old equipment until reaching the end of “usual” life.

“Servicing and repair with R-22 can continue, and the rules allow recovered, recycled or reclaimed R-22 to be used in existing equipment for as long as it is available,” a spokeswoman said.

Sizing up potential damage

Scott Ward of Stevens Engineers figured out the hypothetical environmental costs if all the 450,000 pounds of Freon in Minnesota rinks seeped out into the ozone: A leak that size would be the equivalent of emissions from more than 63,000 vehicles or the CO2 emissions from 34 million gallons of gasoline. It would require 250 acres of forest land to counter its effects.

At the Plymouth Ice Center, rink manager Bill Abel lost about 100 pounds of Freon last year in what he called a typical, slow leak that cost him about $700 to repair with the higher refrigerant prices. Abel intends to convert the two Plymouth rinks still using Freon to an environmentally friendly ammonia system at a cost of $1 million.

Where does he plan to get the money? “That’s a good question,” Abel said. He’s hoping the city or state helps out.

Freon works by changing from a gas to a liquid to a vapor. Ice stays frozen because the chemical pulls heat away from the floor and absorbs it, changing from liquid to vapor as it does the job. Then it goes back through the refrigeration cycle, expels the heat to cool down, turns back into a gas, and is ready to start pulling heat out of the rink floor again.

Craig Flor, president of the Minnesota Ice Arena Manager’s Association, said every industry that uses refrigeration knows about the pending rule changes, it’s just that ice arenas are more affected than, say, grocery or convenience stores. “Most people don’t have a 40-year-old refrigerator anymore,” he said.