United States Nuclear Regulatory Commission - Protecting People and the Environment

Dow Chemical Company

1.0 Site Identification

Location: Bay City, MI
License No.: STB-527
Docket No.: 04000017
License Status: Terminated License
Project Manager: David Nelson

2.0 Site Status Summary

Contamination at the site consists of thorium contaminted slag storage piles. Ground water contamination at the site has been identified. Dow submitted a DP on October 12, 1995. Dow is requesting unrestricted release of the site. The DP was approved in July 1997. In September 2000, Dow informed NRC that decommissioning of the Bay City site had been complicated by a larger volume of contamination than originally estimated, the presence of wetlands, and winter flooding. On April 13, 2005, Dow submitted a revised supplement (Revision 2)to to the DP previously approved DP and on May 6, 2005, Dow submitted Revision 3 of the Health and Safeth Plan. On October 6, 2005, the license was amended to incorporate Rev. 2 of the DP, Rev. 3 of the Health and Safety Plan, and A Groundwater Monitoring Plan. There are no immediate radiological hazards at the site. The licensee has not yet submitted an estimate of the cost of decommissioning.

Dow operated two sites - in Midland, Michigan, and in Bay City, Michigan. Beginning in the early 1940's and continuing into the early 1970's, Dow produced at these two (2) sites a metallic magnesium alloy used in aircraft applications. The alloy was lightweight material with improved high temperature strength. The production process yielded slag material as a by-product. The magnesium-thorium slag material, which is regulated as a radioactive material, has been stored on Dow property at Midland and Bay City sites, Michigan, under a single license granted in 1973 by the NRC (STB-527). The license allowed storage up to 200, 000 pounds of thorium as a slag. The license expired in 1978, but has remained in effect under timely renewal.

Dow submitted a single decommissioning plan (DP) covering both sites and a license amendment request, for NRC review and approval, on October 12, 1995. The DP and subsequent documents that Dow submitted were partially approved in July 1996, and fully approved in July 1997, for unrestricted release. The remediation approach and methods were approved in July 1996. Notice of a Finding of No Significant Impact (FONSI) and Opportunity for Hearing for the issuance of this license amendment were published in the Federal Register on July 19, 1996. Approval of the unrestricted-use criteria, based on Option 1 of the Branch Technical Position (BTP), and the final survey plan, was granted in July 1997. Remediation at the Midland site has been successfully completed and a confirmatory survey of the site was performed by NRC's Region III office in May 1997. The Midland site was approved for backfill in August 1997, and the site was released for unrestricted use by License Amendment No. 8 on March 3, 2000.


The DP approved for the remaining portion (Bay City site) was for the removal of approximately 40, 000 cubic yards of thorium-magnesium contaminated material located over an area of less than one acre. During the initial phase of material removal, new information regarding residual surface and subsurface contamination extending beyond the immediate slag pile area was discovered. So far, Dow has remediated approximately 31 acres at the Bay City site and, according to Dow, the remaining contaminated portion yet to be remediated is about 9 acres. Based on this information, it was determined that a new plan needed to be developed for the removal of the contaminated material. Subsequently, the license was extended through June 2003. During a public meeting between Dow and the NRC staff on September 14, 2000, Dow representatives explained that the wetlands and frequent flooding have complicated the removal of contaminated soils and suggested that an alternate release criteria should be adopted. Dow collected additional soil samples in the saturated zone. Based on the sample results and other information, Dow presented a conceptual approach to revise the approved DP on March 27, 2001, at the NRC Headquarters.

On May 29, 2001, NRC staff requested additional information on Dow's conceptual approach. On August 27, 2001, Dow submitted a supplement to the previously approved DP. During the acceptance review, which included preliminary technical issues, the staff identified omissions/deficiencies and by a letter dated September 25, 2001, rejected the supplement.

On January 31, 2002, Dow re-submitted for NRC approval a revised supplement for license amendment. The Revision 1 was accepted for review and RAIs were sent to Dow on August 30, 2004. On December 31, 2004, Dow responded to the RAIs. On April 13, 2005, Dow submitted Revision 2 of the Supplement to the DP. On October 6, 2005, the license was amended to incorporate Rev. 2 of the DP, Rev. 3 of the Health and Safety Plan, and A Groundwater Monitoring Plan. Other background and cross-cutting considerations are discussed in Appendix 1.

3.0 Major Technical or Regulatory Issues

The staff has not identified any major off-site environmental issues that will not be addressed during decommissioning of the facility. There has been minimal public interest in the decommissioning activities at this facility.

4.0 Estimated Date For Closure


Page Last Reviewed/Updated Friday, May 30, 2014