This page provides information about the cleanup activities for a residential area near a past arsenical pesticide manufacturing site (CMC Heartland Lite Yard Site). A brief history off the project is listed below, for complete details please view the CMC Heartland Lite Yard Site web page.
The CMC Heartland Lite Yard Site (CMC Site) is located in Minneapolis, Minnesota at the northwest intersection of Hiawatha Avenue and 28th Street South. Records show that Reade Manufacturing Company (Reade), an arsenical pesticide manufacturer, had leased and operated on the Site for nearly twenty-five years, from early 1938 to 1963. The Site was used for processing technical arsenic, a white powder, into sodium arsenate, a liquid that was used as a general biocide along railroad lines. Lead arsenate may also have been produced at the Site. US Borax sub-leased the land from 1963 to 1968, and manufactured, stored and shipped arsenic based pesticides for a portion of that period. Soil contamination was discovered in 1994 during reconstruction of the Hiawatha Avenue corridor.
Cleanup at the CMC Site began in the fall of 2004 and was completed in 2005. Soil was removed in a central hot spot on the site where the underlying soil was contaminated to a depth of about 25 feet and additional soil was removed from shallower depths to ensure that no contaminated soil was shallower than four (4) feet from the final surface of the CMC Site after it had been re-developed.
Approximately 62,000 cubic yards of contaminated soil and debris were excavated from the CMC Site. The soil and debris were disposed of at an industrial landfill in Minnesota, and additional soil contaminated with mercury (300 cubic yards) was disposed of at a landfill in Wisconsin.
The Agency for Toxic Substances and Disease Registry (ATSDR), in conjunction with the Minnesota Department of Health (MDH), provided two Health Consultations dated April 8, 1999 and May 17, 2001. These Health Consultations expressed a concern about the possibility of highly contaminated dust being windblown off the CMC Site during the pesticide operations, and noted that no sampling had been done in the residential area located about fifty or more meters northwest of the site.
In June 2001, the Minnesota Department of Agriculture (MDA) and the MDH conducted a limited soil investigation in the residential yards west and northwest of the CMC Site to determine if elevated levels of arsenic were present. A follow-up investigation, using EPA Data Quality Objectives, was conducted in September 2003. The results of these studies indicated that approximately 15 percent of the properties near the CMC site may have elevated levels of arsenic that could pose a health risk to children if ingested.
The MDA asked the U.S. Environmental Protection Agency (EPA) in January 2004 to review the data and address the issues in the Phillips neighborhood located northwest of the CMC Site. In 2004 EPA’s Removal Program sampled over 400 residential properties and completed excavation work at thirty (30) properties which exceeded the removal action level of 95 milligrams per kilogram, or parts per million, (ppm), of arsenic in soil. In 2005, EPA sampled surface soils at over 600 residential properties, 13 day care centers, and four (4) schools and excavated soil at 96 properties that exceeded the removal action level.
Also in 2005, EPA completed an air dispersion computer model which estimated that arsenic contamination from the former plant property could potentially have affected an area within a three-quarter mile radius of the property, which included 3,578 residential properties at that time. In 2006, EPA completed sampling at over 3500 residential properties, including all of the properties that had granted access to EPA within this area. From this sampling EPA identified 206 properties that exceeded the arsenic removal level of 95 ppm. By the end of 2008, 197 of those properties had been cleaned up. The remaining nine (9) properties had unresolved access issues and were referred to EPA’s remedial cleanup program for follow-up.
In September 2007 the EPA added the South Minneapolis Residential Soil Contamination Site to the National Priority List (NPL) of Superfund sites and completed a Remedial Investigation (RI) that included a baseline human health risk assessment. The assessment found that arsenic concentrations greater than 25 ppm could pose an unacceptable risk to residents, primarily from accidental ingestion of contaminated soil.
A Record of Decision for the site was signed on September 5, 2008 and the final cleanup plan was approved. This plan required the removal of soil from residential yards where the arsenic levels exceeded 25 ppm, which was approximately 487 properties. The EPA received funding for the cleanups through the American Reinvestment and Recovery Act and EPA’s contractors began work in August 2009 and completed the cleanups in September 2011. During this period 472 properties were excavated and restored. Some property owners did not allow access for sampling and/or cleanup or respond to request for access from EPA.
During soil cleanup activities, a foot of soil is removed from grass and play areas, while 18 inches of soil is removed within gardens and planting beds. No soil is removed from beneath buildings or paved areas. If soil samples collected at a depth of one foot show arsenic at levels above 95 ppm, workers remove additional soil until sampling shows that remaining soils do not exceed 95 ppm. The higher concentration of arsenic is acceptable at depth due to the decreased contact with the deeper soil. The yards are then filled with clean soil and the properties are restored. The contaminated soil is taken to permitted landfills in Minnesota.
EPA will conduct reviews of the site remedy and attempt to sample and cleanup homes that have not provided access or responded to requests every five (5) years. The first five year review was initiated in 2014, and in 2016, 27 properties were sampled and 11 properties were cleaned up.
Property owners are required by the City of Minneapolis Code of Ordinances Section 248.30(a)(5) to disclose to potential buyers environmental testing completed on the property by or under the direction of EPA or other governmental agencies. For properties that need cleanup but did not grant access, the city of Minneapolis has assured that rental property permits will not be issued.
To receive soil sampling results for your residential property please contact:
U. S. Environmental Protection Agency
Remedial Project Manager
Minnesota Department of Health (MDH)
Collection and Analysis of Soil Samples for Arsenic, Recommended Procedures for Homeowners-Renters-Residents (PDF: 52 KB / 1 page)
How to Reduce Accidental Intake of Contaminated Soils
Project Manager, Incident Response Unit
Greg.Hanson@state.mn.us ~ 651-201-6681
Supervisor, Incident Response Unit
Cathy.Villas-Horns@state.mn.us ~ 651-201-6697