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Fact Sheet

December 2011

Fourth Five-Year Review to Begin, Northwestern States Portland Cement Company 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 has initiated the fourth five-year review of the Northwestern States Portland Cement Company site in Mason City, 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.

Cement has been manufactured at the facility since 1908. Before the cleanup, a by-product 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 high levels of alkalinity and dissolved solids 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. Although the Holcim Cement manufacturing facility is not currently operating, Holcim continues to maintain and operate the treatment system.

The conclusions of the third Five Year Review were that the remedy was functioning as intended and was protective of human health and the environment.


EPA will study site information during this fourth five-year review and inspect the site to determine if the remedy continues to protect human health and the environment. EPA encourages members of the community to ask questions and report any concerns about the site. A final report will be prepared at the end of the review and will be available at the site information repositories.


The site administrative record is available at the following locations during normal business hours:

EPA Records Center
901 North Fifth Street
Kansas City, Kansas

Mason City Public Library
225 Second Street SE
Mason City, Iowa

EPA is committed to keeping the community informed about site activities throughout the cleanup process.  If you have any questions regarding ongoing and planned response actions, please contact:

Ben Washburn
Community Involvement Coordinator
EPA Region 7
901 N. Fifth St.
Kansas City, KS 66101
(913) 551-7003
Toll-free: (800) 223-0425
email: washburn.ben@epa.gov

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