By Mark Ackerman

DENVER (CBS4) – From 2011 to 2014, the Colorado Department of Public Health and Environment handed out more than $2 million in grants to help school districts and municipalities install athletic fields and playgrounds made from recycled tires, commonly referred to as “crumb rubber.”

LINK: List of communities that have received CDPHE funding for crumb rubber fields

PHOTO GALLERY: Crumb Rubber Fields

Colorado has one of the largest “tire pile” problems in the country. To help eliminate waste tires, the CDPHE tire recycling grants were implemented to incentivize the use of recycled tires in the form of play surfaces.Crumb rubber fields in the metro area

Starting in 2014, a series of news reports questioned the safety of crumb rubber athletic fields focusing on possible links between crumb rubber and cancer. In February, government scientists from the Environmental Protection Agency and Centers for Disease Control and Prevention launched a new study to try and determine if crumb rubber poses a health risk.

Also in 2014, Colorado lawmakers passed House Bill 14-1352 The Waste Tire End Users Fund, which effectively morphed the grant program into a rebate program. However, since the new bill took effect only three rebates have been approved for a total of $8,560.

When CBS4 asked the CDPHE if it was promoting a “safe product,” CDPHE said it did not have a “crumb rubber” expert on staff and declined an on-camera interview request, deferring to the ongoing study being conducted by the EPA & CDC.

Mark Ackerman is a Special Projects Producer at CBS4. Follow him on Twitter @ackermanmark