Former U.S. Department of Agriculture Grain Storage Sites

The Problem

Carbon tetrachloride was used in the past as a fumigant to control insects in the grain storage bins used in the CCC grain storage program. Use of the chemical eventually contaminated soil and groundwater at some of the USDA grain storage locations.

Contaminants of Concern

The main contaminant of concern at the USDA grain storage areas is carbon tetrachloride, a known possible human carcinogen. Its use has now been banned and only continues to be used in some industrial applications. When carbon tetrachloride breaks down, it can form other contaminants of concern such as chloroform. Chloroform can easily evaporate and accumulate as a gas. Long-term exposure to chloroform may cause adverse health effects.

What’s Been Done

USDA identified 83 former grain storage sites for potential carbon tetrachloride contamination in Missouri. Beginning in 1999, EPA and the department conducted limited site assessments at these sites to determine presence of contamination and risk of exposure to individuals or populations. These assessments were then used to prioritize investigation and cleanup of the sites found to be contaminated.

Based on the initial screening, 21 of the 83 sites were determined to require no further action. Additional investigation will occur at 57 sites to determine a need for further action. Five sites are preparing for cleanup.

What’s Left

USDA is working to fully characterize sites where contamination has been detected at levels posing a risk to human health or the environment. The first step includes obtaining property access from private landowners at or near the former grain storage sites to complete each investigation and determine the need for additional action.

USDA is in the process of preparing feasibility studies to select remedial alternatives at sites that have been fully characterized and a remedial action has been determined to be necessary to protect human health and the environment. 

USDA is evaluating the remaining former grain storage sites for potential carbon tetrachloride contamination.

Description

In the 1940s, the CCC was created within the USDA to stabilize, support and protect farm income and prices, while distributing and maintaining adequate supplies of agricultural products in the United States. As part of this objective, the CCC started large-scale grain bin construction projects throughout the U.S. in the late 1940s for storing surplus grain. By the early 1970s, CCC ended this grain storage program and sold all existing grain storage bins and equipment. 

The Problem 

During storage, the grain was fumigated to control destructive insects. The most commonly used fumigant was an 80/20 mixture of carbon tetrachloride and carbon disulfide. Soil and groundwater contaminated with carbon tetrachloride has been discovered around some of these grain storage areas.

The U.S. Environmental Protection Agency determined carbon tetrachloride is a probable human carcinogen. Exposure to the contaminants may occur through ingesting contaminated groundwater or inhaling contaminants through vapor intrusion in structures from contaminated soil or groundwater.

Environmental Restoration

There are 83 former grain bin sites identified in Missouri, of which 62 are active or pending additional investigation. The USDA is in the process of investigating and characterizing five sites, and evaluating the remaining 57 former grain storage sites for potential carbon tetrachloride contamination.

Cleanup work being conducted at the site is being performed by the Farm Service Agency (FSA) of the USDA, on behalf of the CCC. The department is providing oversight for these site investigations under an intergovernmental agreement. The agreement between the department and FSA was signed Jan. 3, 2006.

USDA began its investigation on Sept. 30, 2010, looking at five sites for carbon tetrachloride contamination. These sites are located in or near the towns of Savannah, Albany, Montgomery City, Forest City and Nevada. Phase I investigation objectives at these five sites include:

• Update the previous department inventory and status of private wells in the area of the former grain bin sites and sample the identified wells.
• Investigate for the presence of carbon tetrachloride contamination in the soil, as a possible source of contaminated groundwater present beneath the former grain bin sites.
• Gather initial information on the site-specific geology at the former grain bin sites.
• Establish initial groundwater monitoring points to investigate the patterns of groundwater movement affecting possible contaminant migration near the former grain bin sites.

The Phase II investigation objective is to fully define the amount and location of carbon tetrachloride contamination beneath the former grain bin sites and the extent of any off-site contamination for cleanup purposes.

The status of investigations at the five initial sites include: 

• Phase I and Phase II investigations have been completed and a pilot study is ongoing at the Albany site 
• Phase I investigation has been performed at the Montgomery City site
• Phase I and Phase II investigations have been performed at the Savannah site
• Phase I investigation is ongoing at the Nevada site
• Phase I investigation has been paused due to lack of access to the Forest City site

What’s Left

The USDA is continuing work to complete screenings at the remaining 57 former grain bin locations to determine if further site investigation and remediation are required. The USDA is currently in the process of continuing site characterization, and preparing feasibility studies for the five originally selected sites.

*EPA was unable to screen some sites due to lack of access to property or because they were unable to locate the site.

*Records indicate the Montgomery City #2 site is co-located with the Montgomery City site. Both sites are being addressed under the single entry for Montgomery City.