The Helena Chemical Company (HCC) facility located in Mission, Texas, was used for pesticide formulation from 1950 to 1972. The facility is located in a primarily residential neighborhood and currently incorporates five structures within the property boundary (Attachment 2). Soil samples collected in 1980 from the HCC site and surrounding areas indicated elevated concentrations of various pesticides. A lawsuit was filed on behalf of the EPA against the two former owners of the facility, HCC and the Tex-Ag Company. As a result of the lawsuit, the former owners entered into a Consent Decree to remediate the contaminated properties. In 1982 the most highly contaminated soils on the HCC facility site were excavated to a depth of six inches below ground surface (bgs) and buried on site within a soil repository. The repository was capped by a six-inch layer of caliche that was overlain by a one-inch layer of asphalt. In 1983 a Federal District Judge in Brownsville, Texas, ruled that all cleanup activities specified in the Consent Decree had been carried out (Shaw 2004). The Texas Commission on Environmental Quality (TCEQ) remediated residential areas adjacent to the Site in August, 2003.
During the TCEQ remediation of the residential areas, they observed the weakness and failures of the cap. They contacted EPA’s Site Assessment Team to request a new Preliminary Assessment / Site Investigation (PA/SI) to be conducted at the site for Hazard Ranking System (HRS) analysis. The HRS analysis resulted with the Site not qualifying for inclusion on the National Priorities List (NPL). The Site was referred for consideration for a potential Removal Action due to the deteriorating cap.
In late September 2006, the U.S. Environmental Protection Agency (EPA) began the removal clean up at the Helena Chemical Company facility (site) in Mission, Texas. The removal action involves digging up the contaminated soil within the on-site facility property underneath a deteriorating asphalt cap.
On November 21, 2006 a 1,000 gallon underground storage tank (UST) was unexpectedly found in excavation Area #1 during the removal of contaminated soil near the corner of W. Sixth St. and Holland Ave. The tank was found to approximately 3 to 4 feet below ground surface. During excavation activities EPA contractors immediately noticed a strong petroleum odor and proceeded to conduct a ‘head space’ test with an air monitoring device for volatile organic compounds (VOCs). Elevated levels of VOCs were detected has high as 25 ppm. Upon further investigation, it was observed that the tank contains holes and appears to have saturated the soil underneath it. EPA contractors have safely removed the tank and have secured it on site for further clean up and disposal.
Excavation of contaminated soils continued in excavation areas #1 through #3. A depth of approximately 1 to 5 feet have been removed from each 25 foot square grid. Maps can be found online in the 'documents' section of this web site. The maps are labeled 'Primary and Secondary Excavation Maps.' As of November 22, 2006 the excavation of Area #1 through Area #3 is 100% complete, Area #4 is 4% complete, and Area #5 is 5% complete.
To date, EPA has excavated and stockpiled approximately 1,800 cubic yards of soil for further analysis and waste characterization. To date, EPA has removed approximately 300 cubic yards of contaminated soil for off site transportation and disposal. Approximately, 19% of Area #1, 9% of Area #3, and 4% of Area #4 have been confirmed by soil analysis to be below Texas Risk Reduction Program levels for commercial / industrial levels for all contaminants of concern.
Excavated soils are being stockpiled on Site for further analysis and waste characterization. A plastic sheathing is being used to cover all stockpiles and excavated holes on Site to minimize offsite migration of odors, dust, and the potential for contaminated storm water runoff. A frac tank has been mobilized on Site and will be used for containment and water quality sampling of any potentially contaminated storm water.
A network of air monitoring and air sampling devices have been deployed during evening and night hours in the neighboring community around the Site to ensure air quality standards are met. All data will be made available to the public immediately after a through laboratory analysis is completed. Air monitoring and sampling is also being conducted at excavation and stockpile areas on Site to ensure air quality standards are met.
To date, a total of 575 air samples of dust and vapors, 25 soil samples, and 2 water samples have been sent to an independent EPA approved laboratory for analysis since mobilization on site September 29, 2006. All pesticide levels on site and in the community have been below action levels of concern.
An EPA community office trailer is available on Site. A map which will have updated daily information on particulate air monitoring data is being posted next to the entrance of the office trailer for the public to stop by and view. This information will also be available in hard copy and electronic format. The office is open to allow community members an opportunity to speak with an EPA representative in person about any questions or concerns they may have about ongoing Site activities. This office has up to date and current information available in both English and Spanish.
Review soil analysis for waste profiling and characterization.
Approve transportation and disposal facilities proposals for the offsite disposal of contaminated soils. Based upon sampling results, contaminated soil will be properly disposed of in accordance with Federal and state guidelines.
Transportation and disposal of contaminated soil from Site.
Continue excavation of contaminated soil underneath asphalt cap.
Continue to conduct air monitoring and sampling on Site and in the community.
Continue off site transportation and disposal of contaminated soil.
Health and safety concerns have been raised about dust that may be potential contaminated migrating offsite during the clean up process.
An extensive network of air monitoring and air sampling safe guards are being utilize on Site and within the neighboring community. All scientific data will be quickly analyzed and made public for city and community leaders to review and discuss with the EPA. Dust control techniques are being used during soil excavation to reduce and / or eliminate offsite migration of dust.
EPA is committed to the public health and safety of its workers and the neighboring community. Results of the air monitoring and air sampling have indicated that the dust control measures taken are effective.
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