Rockwool Industries (Rockwool), a manufacturer of fiber insulation, operated at the site from about 1974 to 1982.  During its operation, Rockwool leased property from the City of Cameron and produced fiber insulation with several sources of metal slag.  It is believed that the facility may have used lead slag for a short period of time when it was in operation but primarily used steel slag which contains the non-toxic heavy metal iron.  Sources familiar with Rockwool’s operation believed some lead containing materials were buried on the site.  Utility workers placing subsurface power lines observed material buried on-site when they were trenching.  After Rockwool ceased operations, the city of Cameron leased the property to Midwest Hanger, a coat hanger manufacturing company, from 1992 to 2003.  In 2007, the city of Cameron sold the property to Sukup Manufacturing Co (Sukup), a grain bin manufacturer.  Sukup currently conducts distribution operations at the site.

The Rockwool site is located approximately three miles west of Cameron, Missouri, on County Road A.  The Rockwool Site is approximately 20 acres in size and contains an L-shaped metal framed building where Sukup, a grain bin manufacturer, currently conducts distribution operations.  The site lies on the margin of the Cameron urban area in a non-forested rural setting with dominantly agricultural usage.  The site is surrounded by farmland and open fields except for the Cameron Memorial Airport located south of the site.  The portion of the site where lead was found at high concentrations is located northeast of the electrical substation.

The primary contaminant of concern at this site is lead and lead compounds.  Lead and lead compounds are hazardous substances as defined by section 101(14) of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), listed at 40 CFR § 302.4, and have been detected in the groundwater and soils at the site.  EPA has documented total lead concentrations in soil at the site at levels exceeding the industrial soil screening level of 800 ppm.  Lead contaminated soils may migrate via airborne dusts, surface runoff, percolation into groundwater, construction activity, and tracked indoors by foot traffic.  Lead is classified by the EPA as a probable human carcinogen and is a cumulative toxicant.  A significant amount of lead that enters the body is stored in the bone for many years and can be considered an irreversible health effect.

In response to citizen concerns, the Missouri Department of Natural Resources (MDNR), with assistance from the EPA, conducted an environmental investigation at the former Rockwool facility in Cameron, Missouri.  Laboratory analysis of surface soil samples collected from around the concrete foundations document that a release of the hazardous substances including arsenic, cadmium, chromium, copper, lead, mercury, and zinc has occurred at the site.  Arsenic was found in soil samples collected from the site at 66 mg/kg, which exceeds the industrial screening level of 1.6 mg/kg.  Additionally, lead was found in soil samples collected from the site at 1,640 mg/kg which exceeds the industrial screening level of 800 mg/kg.  Groundwater samples collected from the Rockwool site had high levels of arsenic, cadmium, chromium, copper, lead, manganese, nickel, thallium, vanadium, and zinc when compared to drinking water standards.  Lead was measured in two groundwater samples at 2,060 ug/l and 4,340 ug/l.  The maximum contaminant level (MCL) for lead in drinking water is 15 ug/l. Copper was measured in the same two groundwater samples at 1,980 ug/l and 20,400 ug/l respectively.  The MCL for copper in drinking water is 1,300 ug/l.  Although, the drinking water exposure pathway is unlikely, the presence of high levels of metals in the groundwater show metals on-site are leachable and have the potential to migrate off-site.

The EPA has conducted two additional investigations of the site to further characterize wastes buried on-site.   First, in March 2009, the EPA and Cameron Public Works Department conducted re-excavation near the substation at the former Rockwool Industries Site.  City workers had told the EPA that they had encountered unusual material while installing a subsurface electrical line several years ago.  The EPA collected samples of the material and submitted the samples for laboratory analysis.  Sample results determined Toxicity Characteristic Leaching Procedure (TCLP) concentrations at 54.4 mg/L for lead (TCLP Limit is 5 mg/L) and 108,000 mg/kg total lead in soil (exceeding the industrial screening level of 800 mg/kg).  Additionally, arsenic concentrations in the soil were found to be 1710 mg/kg, exceeding the industrial screening level of 1.6 mg/kg.  The EPA conducted an additional investigation of the site in October 2009, in response to information provided by an individual who remembered materials were buried on the site during Rockwool’s operations. The EPA collected subsurface samples from about a one acre area located northeast of the City’s electrical substation.  Analysis of the samples indicated the presence of lead concentrations of 110,000 mg/kg and a TCLP of 195 mg/L lead.  Again, the lead concentrations exceed the industrial screening level of 800 mg/kg and the TCLP limits of 5 mg/L.