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Tire recycling facility CH2E is seen on June 17, 2021 in Hudson. CH2E, located about 30 miles northeast of Denver, owns and operates the largest waste tire monofill in North America. (Olivia Sun, The Colorado Sun)

The nation’s biggest tire dump, 30 miles northeast of Denver, caught fire last July and burned millions of tires in a plume that blocked out the sun for firefighters. The blaze was caused by the owners’ tire-shredding equipment. 

A subsequent state inspection found CH2E’s Tire Mountain near Hudson had for two years ignored state law requiring two tires to be recycled for every one accepted at so-called tire “monofills.” 

The state also found the owners had stiffed them on required tire disposal fees for three quarters of 2020.

Fire roads between the tire piles were blocked. Tires were stacked higher than permitted. Tires were dumped in weeds outside of permitted trenches. Weeds grew everywhere, creating more fire hazards.

The state health department in May responded to these violations with a fine totaling $8,704. Officials also ordered the owners to not do any of it again before the dump and its nearly 27 million tires must close for good in 2024. 

State hazardous waste officials explain the low fine by saying they have a 15-page compliance order requiring significant changes in operations by the Tire Mountain owner, CH2E, and that the company has already carried many of them out. 

Snapp said regulators are limited by hazardous waste inspection rules. “We can only assess a penalty for the violations that occurred within that one day that we inspect the site, and it’s a maximum of $10,000 per penalty per day,” he said. 

A huge plume of black smoke billowed from the monofill near Hudson, previously known as Tire Mountain, when tires caught fire on July 22, 2020. (Platteville-Gilcrest Fire Protection District)

Most important, said David Snapp, manager for the state’s solid waste and materials management program, is that the consent decree is “enforceable. So it’s quick, it’s faster, otherwise, we would have to develop our case, file a complaint in court, and that’s just very bulky and time consuming. And it costs the state a lot of money.” 

CH2E has not returned multiple calls for comment since last July’s tire fire. 

Colorado has historically had some of the worst tire dump problems in the nation. In addition to the monofill near Hudson, state officials frequently inspect and negotiate enforcement with a slowly-emptying tire pit south of Fountain, and a facility near Sterling. 

The Rattlesnake Solar Farm sits on 175 acres just east of CH2E the largest waste tire monofill in North America, previously known as Tire Mountain located in Hudson, Colorado. (Carl Payne, special to the Colorado Sun)

State legislators periodically set new waste-tire fees and closing dates for the tire facilities, then move dates down the road when the economics of tire recycling change again — usually for the worse. The current state law from 2018 says monofills must stop burying incoming tires by 2024. The same law says in the meantime, monofills must recycle and reuse two tires for every tire put in the ground. 

Legislators also revived a disposal fee that buyers pay when they change out their car tires. Licensed tire dumpers also pay the fee to monofills when they drop off tires. The collected money goes into a user fund the state pays out to those recycling old tires — most often to cement kilns burning tires for fuel, or landfills using shredded tires as daily garbage cover. 

During the shortened 2020 pandemic-influenced legislature, though, lawmakers swept the user fund away to fill other budget holes. Snapp said he thinks the fund, now accumulating again, will start to attract recyclers this year. Regulators will propose an increase in the payments to end users, currently $50 a ton, to draw even more interest, he said. 

Sterling’s facility has often gotten waivers from state regulators on the 2-for-1 rule because it doesn’t have a cement kiln or other tire-recycling entrepreneurs nearby. 

The tire monofill south of Florence has drawn down millions of buried tires by shipping them to nearby cement plants, and is running out of material it can safely take out of the ground, Snapp said. Some of that monofill’s original tire pits went 50 feet deep, and the scrapped tires will likely have to stay there, Snapp said. 

The Hudson facility in the past had thinned out its tires, spread among 64 “cells,” for cement-plant fuel. But those users disappeared, and it costs too much to ship tires in bulk to the cement plants near Florence. CH2E advertises multiple uses for shredded tires on its web site, but started falling behind the 2-to-1 ratio a few years ago. 

The fire on July 22 raged for a day and burned millions of tires spread among a handful of the cells. The state put off its scheduled annual inspection until November in order to let the company clean up from the fire, Snapp said. 

When inspectors finally went to Hudson, they found required fire roads around the cells blocked by piles of dirt used to put out the fire, as well as extensive weeds. Tires were piled outside of the cells, against state rules, and stacked higher than regulations allow. 

When the state asked to look at paperwork, regulators found a new set of violations. The new tire law taking effect at the beginning of 2018 allowed the state to grant waivers on the 2-to-1 recycling ratio for that year alone, and CH2E got one. It did not get one for 2019 or 2020, according to the state, but nonetheless kept taking in more tires than it recycled. 

The company had also stopped passing on tire disposal fees paid by dumpers, for the first three quarters of 2020. CH2E caught up on those payments by the time it agreed to the consent order in May, Snapp said. 

The tire cells that burned are full of melted rubber, ash, and the steel belting left behind. They’re covered in dirt and sand, Snapp said. Large disposal facilities like Tire Mountain are designed according to state regulation to prevent leaking of any chemicals into groundwater. State tests have not detected any hazards from the burned cells, Snapp said. 

Now when CH2E or subcontractors operate shredders, which heat up from the heavy work, they will have to cover nearby cells to avoid fires spreading, Snapp added. 

The consent decree reiterates state law saying CH2E will stop accepting newly-disposed tires in 2024, and cover remaining piles according to state rules. However, the company could keep some cells open to pluck out tires if it has viable recycling options for those tires. Snapp said he thinks more area landfills will begin using shredded tires for “daily cover” again if they can benefit from the user fund. 

Regulators point to one more concession they feel was important to get from CH2E. As part of the decree, the company must amend its property title with Weld County to let a future buyer beware what’s underground. 

“To in perpetuity notify any potential purchaser of the property that the land has been used as a landfill,” the consent decree says.

Michael Booth

Michael Booth is a Colorado Sun reporter covering health, health policy and the environment. Email: Twitter: @MBoothDenver