Third Five-Year Review Completed, Northwestern States Portland Cement Co. Superfund Site, Mason City, Cerro Gordo County, Iowa
The U.S. Environmental Protection Agency conducts regular five-year reviews on Superfund sites where cleanups have been completed. These reviews are required by the Superfund law [42 U.S.C. Section 9621 (c)]. EPA Region 7 and the Iowa Department of Natural Resources have completed their third five-year review of the Northwestern States Portland Cement Company site in Mason City, Cerro Gordo County, Iowa.
The site consists of a portion of the Holcim (U.S.) Inc. (formerly Northwestern States Portland Cement Company and Holnam Inc.) cement manufacturing facility located north of Mason City, Iowa, near the intersection of 25th St. and U.S. Highway 65.
The Holcim facility has made cement since 1908. Before the cleanup, a byproduct of the cement making process known as cement kiln dust (CKD) was disposed on the site. It caused visible sediment in the surface water of Calmus Creek as well as the high alkalinity and high level of dissolved solids found in the creek and in the area ground water.
An area referred to as the West Quarry was mined for limestone, a raw material for cement production, until 1950. In 1969, Holcim began using the West Quarry for the disposal of CKD. Disposal of CKD in the West Quarry ceased in 1985 and the open portion of the quarry filled with water.
Under EPA oversight, Holcim installed a system to dewater the West Quarry and treat the collected water. An engineered clay cap was placed over the area of the West Quarry filled with CKD. Access to the area is restricted. Holcim continues to maintain and operate the treatment system.
The Five-Year Review
During this third five-year review EPA and the Iowa Department of Natural Resources inspected the site as one element of the review. They also considered annual status reports, site records, and the previous five-year review before concluding that the remedy at the site remains protective of human health and the environment.
The Five-Year Review report and the site Administrative Record is available at the following locations during normal business hours:
EPA Records Center
901 N. Fifth St.
Kansas City, KS
Mason City Public Library
225 Second St. SE
Mason City, Iowa
Questions or requests for information can be submitted to:
Community Involvement Coordinator
EPA Region 7
901 N. Fifth St.
Kansas City, KS 66101
Toll free: (800) 223-0425