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EPA in Iowa

Monsanto Company/Bayer CropScience LP Facility, Muscatine, Iowa - Fact Sheet, July 2020

Public Comment Period for Draft RCRA Corrective Action Permit


EPA Region 7 invites the public to review and comment on the draft Resource Conservation and Recovery Act (RCRA) Corrective Action Permit for the Monsanto Company/Bayer CropScience LP facility, located at 2500 Wiggens Road in Muscatine, Iowa. The 45-day public comment period runs from July 15, 2020, to Aug. 28, 2020. The permit requires corrective measures to maintain a plume of groundwater contamination within the facility property boundary.


The facility property includes approximately 585 acres. Approximately 160 of those acres are developed for the manufacture and formulation of herbicides for agricultural use; manufacture of chemical intermediates for herbicide production; and packaging of herbicides and seed treatment chemicals. Past operations have resulted in the release of chemicals to the environment, resulting in contamination of groundwater.


The primary contaminants detected in groundwater are monochlorobenzene and diallate.  Every 10 years, an expanded analysis is done for 40 CFR section 264 Appendix IX (Appendix IX) analytes to determine if additional chemicals need to be monitored.


The permit requires the following corrective action: pump groundwater at a rate sufficient to maintain the contamination beneath the facility property; operate a focused pump and treatment system in the area of highest contamination; and monitor contaminant concentrations to evaluate progress towards attaining cleanup goals. The cleanup goal for monochlorobenzene is 100 micrograms per liter and for diallate is 98 micrograms per liter. As proposed in the permit, the groundwater program will continue until the cleanup goals are met and maintained for three consecutive years.


The initial permit renewal application was submitted to EPA by Monsanto Company, the owner and operator of the permitted facility. Subsequently, Monsanto Company submitted a Class 1 permit modification request that requires prior approval from the Administrator of EPA Region 7, with a revised Part A application that notified EPA of a change in the owner and operator of the facility from Monsanto Company to Bayer CropScience LP. The owner/operator change is planned to occur on or around Aug. 1, 2020, during the public comment period for the permit reissuance. With the draft permit, EPA approves the owner/operator change and includes both names, Monsanto Company and Bayer CropScience LP, in the permit with anticipation that the notified change will occur by the time the permit is reissued. When the permit is reissued, it will be issued to the then owner/operator of the facility.

In the Corrective Measures Performance Evaluation Report, dated July 31, 2018, the permittee provided data to support a request that the required monitoring frequency for four of the 16 monitoring wells sampled as part of the groundwater monitoring program be reduced from semiannual to annual. EPA has reviewed the request and grants the reduction in frequency to annual for Wells SP-76, SP-77, SP-79, and SP-80, as it will not impact the protectiveness of the corrective action program.

Two chemicals, triallate and alachlor, have been detected and are associated with the facility.  These chemicals have not been recently analyzed and are not in the expanded list of analytes to be analyzed once every 10 years (i.e., Appendix IX list). In the permit, EPA is requesting an initial sampling and analysis for triallate and alachlor and the addition of these two chemicals to the Appendix IX list analyzed every 10 years.

The permittee notified EPA that Production Well 1 was replaced by Production Well 14 and appropriate permit actions were taken regarding this replacement. As such, the permit was modified to replace the requirements that applied to Production Well 1 with those for Production Well 14.


The permit also imposes other restrictions and requirements on the facility property to be protective of human health and the environment. Residential use is prohibited. Any significant change in the facility use that could impact the protectiveness of the corrective action program requires evaluation for such impact and notice to EPA. Future construction over the groundwater contamination must address the potential for vapors moving up from the groundwater into occupied structures (i.e., into the human breathing space). The permit requires that physical controls, such as a fence and locks, be maintained to secure wells. A procedure must be adhered to during construction projects to protect against exposure to contamination, notify EPA if contamination is encountered, and manage materials and soil appropriately. Red-stained soil was encountered when sampling under a continually used tank, the source of which could not be identified at the time. The permit requires this soil to be removed or remediated when the tank is removed.


The public is encouraged to review and comment on the draft RCRA Corrective Action Permit for the Monsanto Company/Bayer CropScience LP facility. The permit and other supporting documents are contained in the Administrative Record and are available at the locations listed below during normal business hours. For the operating status and hours of each location where the records are kept, please call the relevant number provided below. If the Administrative Record is not physically available (e.g., due to COVID-19) an index and/or electronic copy can be provided upon request by contacting Ben Washburn (see below).

Musser Public Library  
408 East 2nd Street
Muscatine, IA 52761

Iowa Department of Natural Resources
502 East 9th Street
Des Moines, IA 50319

EPA Region 7 Records Center
11201 Renner Boulevard
Lenexa, KS 66219

Guidelines for Commenting:
  • Explain your views.
  • Tell us if you support or disagree with the permit conditions. Please be specific.
  • Provide alternatives if you disagree with permit conditions.
  • Submit comments by Aug. 28, 2020.

A formal Public Hearing has not been scheduled, but will be held if there is sufficient public interest. Requests for a Public Hearing must be made in writing to Mary Grisolano at the address listed below for receipt by Aug. 28, 2020.  The request should state the nature of issues to be raised at the hearing. EPA will evaluate any request and hold a formal hearing if it finds that a hearing will contribute to the decision-making process by clarifying significant issues affecting the cleanup remedy.

EPA will issue a final RCRA Corrective Action Permit to Monsanto Company/Bayer CropScience LP, only after the public comment period ends and all comments are reviewed. EPA may modify the permit based on any new information and comments from the public.


You may submit written comments or written requests for a public hearing to:

Mary Grisolano
EPA Region 7 (LCRD/ROAG)
11201 Renner Boulevard
Lenexa, KS 66219

If you have any questions or want to receive a copy of the Administrative Record or further information, please contact:

Ben Washburn
Community Involvement Coordinator
U.S. EPA Region 7 (ORA/OPA)
11201 Renner Boulevard
Lenexa, KS 66219