ROCKFORD — The Illinois Environmental Protection Agency oversaw the removal of more than 4,600 tons of used tires this summer from a former commercial used tire processing business that had been operating in violation of environmental regulations for more than a decade.

The cleanup at S.T.A.R. Used Tire Disposal, 217 Peoples Ave., began June 11 and ended Aug. 3 and cost more than $1.8 million, making it the largest and most expensive used tire cleanup in Illinois history, the state EPA said Tuesday.

“Stockpiles of used tires, like the millions of pounds that were at the S.T.A.R. site, present a true environmental threat and public health hazard due to the risk of fire and as a breeding ground for mosquitoes and other pests,” Illinois EPA Director Alec Messina said in a written statement.

The site’s operator and property owners have been the subject of multiple enforcement actions initiated by the Illinois EPA. The facility operated in violation of the Environmental Protection Act and Illinois Pollution Control Board regulations for more than a decade.

The state EPA invoked its administrative power to hire a Peoria contractor to remove the tires after legal actions to force the owners and operator to remove the tires were unsuccessful. The agency will seek the Illinois Attorney General’s help to sue the operator and property owners to recoup its costs for the cleanup, said Illinois EPA spokesperson Kim Biggs.

Property owners allowed a contractor to access the site so the state’s forced removal action could be completed. Whole tires, truck tire treads and used tire shreds were stored outside and in a building and in semitrailers on the property. Before the tires were removed, the property contained the largest significant waste tire stockpile remaining in Illinois, the state EPA said.

Employees at S.T.A.R. Used Tire Disposal would often use blowtorches to cut old metal wheels on the property, but doing so in proximity to such a large volume of old rubber tires “was potentially very dangerous,” said Timothy Morris, fire prevention coordinator with the Rockford Fire Department. The Fire Department worked with the business owner, Thomas Taylor, to move tires that were stored outside away from electrical power lines and into orderly stacks to allow firefighters better access in the event of a fire.

Biggs said S.T.A.R. Used Tire Disposal had not been operating since approximately 2011. However, Taylor wishes to resume tire processing and disposal work and would need to obtain a “hot work permit” from the Fire Department do so, Morris said. The department would limit how many tires the business can accept and how many it must dispose of per year and ensure that proper safety measures are in place before issuing the permit, Morris said.