GENERAL MILLS/HENKEL CORP.
On this page:
- What Is Being Done to Clean Up the Site?
- What Is the Current Site Status?
- EPA’s Involvement at the Site
- Activity and Use Limitations
- Sampling and Monitoring
- Enforcement Information
- Operable Units (opens new page)
- Cleanup Progress (opens new page)
The General Mills/Henkel Corporation site is located on East Hennepin Avenue in Minneapolis, Minnesota. General Mills used the area as a food research facility beginning in 1930, and from 1947 to 1977, also used the site for chemical research. Waste disposal operations between 1947 and 1962 contaminated soil and groundwater with hazardous chemicals. The property was purchased by the Henkel Corporation in 1977 and has since been resold. Soil and groundwater cleanup has occurred at the site, and additional work to address the vapor intrusion pathway is nearing completion. Groundwater monitoring continues at the site.
What Is Being Done to Clean Up the Site?
The site is being addressed by a PRP under Minnesota Pollution Control Agency (MPCA) oversight. The site is part of EPA's Enforcement Deferral Pilot Agreement with MPCA. MPCA is the primary agency overseeing cleanup at the site.
MPCA has conducted several five-year reviews of the site’s remedy. These reviews ensure that the remedies put in place protect public health and the environment, and function as intended by site decision documents. The most recent review, conducted by MPCA in 2014, concluded that response actions at the site are in accordance with the remedy selected and that the groundwater and soil remedies were protective. However, the review concluded that the air (vapor intrusion) pathway was protective in the short-term, but that to ensure long-term protection, the ongoing source of the contamination should be addressed. The review also made additional recommendations regarding improvements to land use controls and groundwater monitoring.
What Is the Current Site Status?
The site’s long-term remedy included groundwater pumping to prevent further migration of contaminants and to improve groundwater quality. The groundwater pumping system began operating in 1985 and shut down in 2010. Currently, General Mills, under the oversight of the Minnesota Pollution Control Agency (MPCA), is nearing completion of a program to sample vapor beneath homes near the site and install ventilation systems where needed. MPCA is also continuing to evaluate the status of groundwater cleanup at the site. Groundwater monitoring is ongoing.
EPA’s Involvement at the Site
This site is part of EPA's Enforcement Deferral Pilot Project. MPCA is the lead agency overseeing cleanup and enforcement for the site. General Mills first performed soil and groundwater sampling during the 1980s with oversight by the MPCA. A Consent Order between General Mills and the MPCA, including a Response Action Plan, was signed in 1984. The selected cleanup action consisted of groundwater pumping to prevent further migration of contaminants and to improve water quality in the aquifer. The groundwater pumping system began operating in 1985.
In 2001, General Mills performed additional soil assessment near the former absorption pit. MPCA concluded that surface soils (zero to four feet) did not present a risk. The groundwater pumping system continued operating until 2010, when MPCA approved a trial shut-down to test whether groundwater cleanup levels could be maintained without pumping.
In 2012, General Mills conducted soil gas sampling at the site and in the surrounding neighborhood which confirmed the presence of TCE in soil gas at levels that could cause vapor intrusion risk. With the oversight of MPCA, General Mills undertook additional investigations and installed vapor mitigation systems where needed. In 2014, MPCA’s Consent Order with General Mills was modified to require the ongoing actions for vapor intrusion.
Activity and Use Limitations
At this site, activity and use limitations that EPA calls institutional controls are in place. Institutional controls play an important role in site remedies because they reduce exposure to contamination by limiting land or resource use. They also guide human behavior. For instance, zoning restrictions prevent land uses – such as residential uses – that are not consistent with the level of cleanup.
For more background, see Institutional Controls.
Groundwater is contaminated with volatile organic compounds (VOCs), primarily trichloroethylene (TCE). Soil was also previously contaminated with VOCs.
Sampling and Monitoring
The site is part of EPAs Enforcement Deferral Pilot Agreement with the Minnesota Pollution Control Agency (MPCA) and MPCA is the primary agency overseeing cleanup at the site.
During cleanup, a site can be divided into a number of distinct areas depending on its complexity. These areas, called operable units (OUs), may address geographic areas, specific problems, or areas where a specific action is required. Examples of typical operable units include construction of a groundwater pump and treatment system or construction of a cap over a landfill.