Back in the early 1990s, illegally dumped tires piled up by the millions across northern Utah.

Those waste piles are shrinking, thanks to the state’s tire-recycling program, funded by a $1 fee on every new tire sold. But a legislative audit released Wednesday found the program’s goals are not being fully realized.

Turns out, Utah motorists are generating far more waste tires than are collected for recycling— despite unused capacity among the four firms authorized to process the old rubber.

Meanwhile, the state’s tire fund has ballooned during the past decade from practically nothing to $4.6 million, indicating that it takes in more money than it spends on cleanups and subsidies that promote recycling.

“We are concerned by the gap between the number of waste tires generated and the number that are recycled,” audit supervisor Matthias Boone told the Legislative Audit Subcommittee on Wednesday.

A consequence of this gap is the accumulation of old tires in places like Lee Kay Ponds west of Salt Lake City. This wetland area, popular with birders who enjoy observing avian life that congregates there in winter, was among four cleanups authorized last year.

Department of Environmental Quality Executive Director Alan Matheson highlighted the Lee Kay cleanup, which removed nearly 4,000 tires, in this year’s “State of the Environment” report.

The audit recommends DEQ’s tire program expand the ways its money can be used. A bill sponsored by Sen. Scott Sandall, R-Tremonton, proposes allowing small counties to recoup the full cost of cleanups, up from the 60 percent currently available.

“The fund could support this legislation [SB46]," Boone said, “and help rural counties with their cleanup efforts.”

Utah is among six states that subsidize tire recycling, but it is the only one that doesn’t track waste tires through a manifest system. Boone recommended DEQ study the feasibility of such a system and maintain a list of all Utah sites where old tires are dumped.

Tires continue turning up in gulches, on shorelines and in vacant lots, Boone said. Cities report that large quantities are dumped overnight or abandoned on leased properties.

These piles bring environmental and public health risks. Tires, which don’t biodegrade or compact, are combustible and leach chemical residues into water and soils. They also harbor disease-carrying rodents and mosquitoes.

Despite the program’s shortcomings, it has led to the recycling of at least 47 million tires since its inception in 1990, as well as the collection of 2.2 million from abandoned stockpiles, according to DEQ’s waste management division.

Last year, the tire fund spent $3 million to support cleanups and the sale of 46,000 tons of products derived from waste tires, typically crumb rubber used on athletic fields and fuel chunks burned in cement kilns.

The two cement producers reported to auditors they would burn coal instead of rubber if not for the incentives provided by the fund. But the audit discovered many holes that tires fall through, preventing them from reaching recyclers.

Of the 25 landfill operators surveyed by auditors, 10 reported burying tires with other waste in violation of state law; eight said they could not afford to transport tires to recyclers; and five reported being unaware of the program’s incentives. Two acknowledged accepting old tires by the truckload, Boone said, far in excess of a four-tire limit on the number landfills can accept at one time from one person.

Matheson appeared before the audit subcommittee Wednesday to endorse the audit’s recommendations.

“We appreciate this audit,” he told lawmakers. “It’s important to get fresh eyes on it.”

He noted, however, that regulations sometimes carry unintended consequences that undermine their purpose.

“That four-tire limit, for example,” he said, “creates an incentive to not bring in their tires, toss it in the gully.”