Kanawha River Dioxin Site

Site Contact:
Deborah Lindsey


Site Location:
Putnam/Kanawha Counties
Nitro, WV 25143

The Kanawha River Site is contaminated with dioxin generated from the past production of 2,4,5-trichlorophenol. The compound was then used to make the pesticide 2,4,5-trichlorophenoxyacetic acid or 2,4,5-T. The 2,4,5-T was produced from 1948 to 1969 at Old Monsanto's Nitro, West Virginia, facility located along the banks of the Kanawha River.

In 1995, the operation and management of the Nitro facility were transferred to Flexsys America LP, a joint venture between Old Monsanto and Akzo Nobel. In 1997, Old Monsanto spun off its chemical businesses, including its interest in Flexsys and the Nitro facility to Solutia, Inc. ("Solutia"). Solutia became an independent company on September 1, 1997. On March 31, 2000, Old Monsanto changed its name to Pharmacia Corporation.

The State of West Virginia had previously established a fishing advisory for the Kanawha River area due to elevated levels of dioxin in fish. The advisory addresses the Kanawha River from the Interstate 65 bridge near St. Albans to the Ohio River, and in the lower two miles of the Pocatalico River and the Armour, Heizer and Manilla Creeks.

Current investigative work has been conducted under an EPA Consent Order signed by Monsanto and Pharmacia Corporation in March 2004 to develop an Engineering Evaluation and Cost Analysis (EE/CA) to reduce the load of dioxin into the river.

In late 2008 and early 2009, Monsanto collected additional fish and sediment samples in its study of dioxin contamination in a 14 mile stretch of the Kanawha River extending from the mouth of the Coal River to the Winfield Dam. The work was conducted with EPA and West Virginia Department of Environmental Protection (WVDEP) oversight. Monsanto prepared a risk assessment, a summary of all the data, and developed various potential ways to address the dioxin contamination for EPA and WVDEP to evaluate.

The EE/CA studied a 14-mile stretch of the Kanawha River from Mile Point (MP) 46 to 32 near the Winfield Dam. The study focused on the area near the old Flexsys/Solutia plant since it was the greatest source of dioxin in the river. The EE/CA also assessed the dioxin risk to human health and the environment.

The EE/CA plan outlined six alternatives for addressing the dioxin contaminated sediment in the Kanawha River. EPA's preferred alternative is Alternative 4, which includes Armored Capping of sediments, Institutional Controls, and Monitored Natural Recovery.

In September 2016, Monsanto established a tentative schedule for fish tissue sampling, bathymetric work, and sediment sampling to run from September through October until completed. This investigative work was conducted from 9/26/16 through 10/24/16. Analytical results from the sampling and bathymetry results are pending.