DSHW-1995-004209 - 0901a06880156e46

Michael O. Leaviu
Governor
Dianne R. Nielson, Ph.D.
Exccucivc Director
Director
Sta% of Utah • q^.a-z^o
DEPARTMENT OF ENVIRONMENTAL QUALITY
DIVISION OF SOLID AND HAZARDOUS WASTE
288 North 1460 West
P.O. Box 144880
Salt Lake City, Utah 84114-4880
[phone] Voice
Dennis R. Downs [phone] Fax
[phone] T.D.D.
September 1, 1995
Mr. Joe D. Thompson, Director
Waste Management and Environmental Services
Thiokol Corporation
P.O. Box 689
Brigham City, UT 84302-0689
Re: Risk Assessment
M-186 Ponds
Dear Mr. Thompson:
In September 1994, the Division of Solid and Hazardous Waste (DSHW) received a request from
Thiokol to close in place, two industrial wastewater ponds located at M-186. This request was to
close the ponds under the risked based closure rules found in R315-101 of the Utah Administrative
Code . After a preliminary review and comments by the DSHW, this report was resubmitted to the
Division on August 10, 1995.
The ponds, when sampled, had been found to contain trace amounts of 1,1,1 Trichloroethane (TCA)
and 1,1 Dichloroethane (DCA). A risk assessment was performed by Thiokol under R315-101. This
assessment found that the risk for exposure or harm to human health and the environment to be
extremely low. The Health Index, as specified in R315-101-1 (3), was five to seven orders of
magnitude less than one. The toxicological information currently available for TCA and DCA is
limited in regards to carcinogenicity. Based on the information provided by Thiokol; the low
concentrations of these contaminants, coupled with the remote location of M-186, leads the
Executive Secretary to agree with the risk assessment findings and grant approval of the Risk
Assessment Report.
R315-101-6 and 7 require Thiokol to prepare a Site Management Plan outlining how closure of the
M-186 ponds will be completed. This plan was included in the draft Risk Assessment Report. After
calculating the risks involved, Thiokol has chosen a "No Further Action" option. Thiokol plans to
remove and manage any storm water from the ponds and then backfill the ponds to grade with clean
native soils. The Executive Secretary has reviewed this plan and grants draft approval.
As a result of draft approval of this plan, a public notice will be given, a 30-day public comment
period will begin and a public hearing will be held. The public comment period will begin on
September 6, 1995 and end on October 5, 1995. The public hearing on Thiokol's proposed Site
Management Plan is scheduled for October 2, 1995 and will take place at 7:00 p.m. at the Brigham
City Library. After any pertinent comments have been incorporated into the plan, the Executive
Secretary will grant final approval and Thiokol will be able to proceed with final closure of the
ponds.
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If you have any questions about this letter, please contact Otis Willoughby at 538-6170.
Sincerely,
Dermis R. Dowrfs
Executive Secretary
Utah Solid and Hazardous Waste Control Board
DRD\OHW\ow
c: John C. Bailey, M.D., M.S.P.H., Health Officer/Department Director,
Bear River District Health Department
NOTICE
The Utah Division of Solid and Hazardous Waste (DSHW) received a request from Thiokol to close
in place, two industrial wastewater ponds located at M-186. These ponds, when sampled, were
found to contain trace amounts of 1,1,1 Trichloroethane and 1,1 Dichloroethane. A Risk Assessment
was performed by Thiokol under R315-101 of the Utah Administrative Code. This assessment found
that the risk for expostire or harm to human health and the environment was below acceptable limits
specified in R315-101. The Executive Secretary of the Utah Solid and Hazardous Waste Control
Board agrees with the risk assessment findings and has granted approval of the assessment report.
R315-101-6 and 7 require Thiokol to prepare a site management plan outlining how closure of the
M-186 ponds will be completed. This plan was included in the Risk Assessment Report. After
calculating the risks involved, Thiokol has chosen a "No Further Action" option. Thiokol intends
to backfill the two ponds with clean native soils. The Executive Secretary has reviewed this plan
and has granted draft approval for the closure.
Following this draft approval and this public notice, a 30-day public comment period and a public
hearing will be held. The public comment period will begin on September 6, 1995 and will conclude
on October 5, 1995. All comments must be received by 5:00 p.m. on October 5, 1995. Comments
should be directed to Otis Willoughby at the DSHW, 288 North 1460 West, Salt Lake City, Utah,
84114-4880, or phone at [phone]. After any pertinent comments have been incorporated into
the plan, the Executive Secretary will grant final approval and Thiokol will be able to proceed with
final closure of the ponds.
A public hearing will be held at 7:00 p.m. on October 2, 1995 in the auditorium of the Brigham City
Library.