St. Louis River-U.S. Steel Superfund Site: Major Chronological Events - 5 Year Chronology Table

Event

Date

Beginning of US Steel operations

1915

Contaminants were found in the river during a survey was conducted by Minnesota State Board of Health, the Minnesota Commission of Game and Fish, and Wisconsin State Board of Health.

1929

Coke plant settling basin was constructed.

1954

Survey conducted by Minnesota Pollution Control Agency (MPCA) found high Biological Oxygen Demand, high pH, and high concentrations of phenols, cyanide, and ammonia in coke plant settling basin.

1973

Steel making discontinued operations.

1975

MPCA requested hydrogeological study of the USS site (Site).

1979

Coke plant discontinued operations.

1979

Old basement full of oily waste found and excavated disposed of out-of-state shortly after.

1981

Site was inspected by the United States Environmental Protection Agency (USEPA)

1982

Site was placed on the National Priorities List (NPL) under Comprehensive Environmental Response, Compensation and Liability Act (CERCLA).

1983

A Request for Response Action (RFRA) was issued.

1983

Site was placed on the Minnesota Permanent List of Priorities (PLP).

1984

Response Order By Consent (Consent Order) between USS and the State of Minnesota was approved by MPCA.

1985

Final phase of Remedial Investigation (RI) began.

1985

The wire mill discontinued operations.

1986

The Record of Decision (ROD) was issued.

1989

Remedial deconstruction began on the coke plant.

1989

Clean up and demolition of the coke plant and appurtenant facilities was completed.

1992

A free liquid mercury spill that was under a meter storage shed was reported and cleaned up.

1992

Response Action Plan (RAP) for implementing the remedy at OU-J and OU-P was submitted.

1996

Solidification of OU-J was completed.

1997

Response actions on the OU-P were completed.

1997

Underground coke oven gas lines were removed and remediated.

1999

Repair on the slumps that developed in OU-J perimeter berm adjacent to Steel Creek was completed.

2001

Estuary sediment investigations begin

2002

First Five-Year Review was completed.

2003

Five-Year Review Recommendation Implementation Report with initial investigation results.

2005

Minnesota Power installation of seven power line towers on-site.

2005

Second Five-Year Review was completed.

2008

Continued soil and tar removals at OU-A

2010-12

Supplemental Five-Year Review Investigation Report with upland sediment investigations was submitted

2011

Remedial Investigation completed for estuary sediments.

2012

Workplan for Final Feasibility Study for estuary sediments submitted.

2012

Phase II Investigation of 132 acres of upland property conducted.

2012

RI report for OU-P, OUQ, OU-S submitted

2013

Upland sediment FS work plan

2013

Upland sediments Treatability Study was conducted (landfill or CDF siting)

2013

Remedial Investigation report completed for estuary sediments. Several other reports for wetland delineation, sediment profile imaging, habitat characterization were submitted.

2013

Feasibility Study report completed for upland and estuary sediments

2015