On May 26th, 2012 the Iowa City Landfill caught fire due to unknown causes. Shredded tire rubber is used at the landfill as a layer to filter leachate from the landfill. This material caught fire in one of the 7-acre cells. On Tuesday, May 29, 2012 the Iowa Department of Natural Resourses (IDNR) called the EPA Duty Officer to request advice on response actions. On Thursday, May 31, 2012, the Unified Command and local officials requested EPA technical assistance with air monitoring at the sites. EPA mobilized its first reponder and members of the Superfund Technical Assessment and Response Team (START) to assist with air monitoring.