Waste and Underground Tank Management Bureau

Phillips 66 Company
Billings Land Treatment Unit
formerly ConocoPhillips Company
Billings Land Treatment Unit
Billings, Montana


ExxonMobil Refining and Supply Company Location Map Location Map


The Phillips 66 Company Billings Land Treatment Unit (ConocoPhillips) is located adjacent to Alexander Road, approximately nine miles north of Billings, Montana.  The legal boundary of the land treatment unit (LTU) encloses about 20 acres of which approximately 11 acres were used for land treatment.  The LTU is divided into seven treatment areas.

The LTU’s Montana Hazardous Waste Permit #MTHWP-99-01 became effective on May 24, 1999 and will remain valid through May 24, 2009, unless revoked and reissued or terminated. 

ConocoPhillips operated the LTU for the treatment of hazardous waste and non-hazardous waste.  ConocoPhillips began operation of the LTU in April 1972.  Waste was applied to the LTU for biological treatment.  Hazardous waste has not been applied to the LTU since 1994.  Non-hazardous petroleum contaminated soils were last applied to portions of the LTU in 2003.  No waste has been applied since 2003.

On February 21, 2008, the Montana Department of Environmental Quality (Department) granted approval for ConocoPhillips to enter the closure period.  ConocoPhillips will not be applying any more waste to the site.  Closure will be completed when ConocoPhillips establishes a vegetative cover on the LTU.  ConocoPhillips will then be required to monitor soil and water at the LTU for 30 years.



Ground water monitoring data has been collected from LTU wells since 1988 and surface water samples have been collected at Twelve Mile Creek since 1989.  Currently, the permit requires that ConocoPhillips monitor four wells, named LF-2, LF-3, LF-4, and LF-6, that are downgradient of the LTU.  A surface water sampling point named SS-2 in Twelve Mile Creek that is downgradient of the LTU is also monitored.  In addition, ConocoPhillips voluntarily monitors a cross-gradient well named LF-14.  These wells and surface water sampling points are sampled and analyzed twice a year.

In an effort to better understand surface water quality in Twelve Mile Creek, the Department directed ConocoPhillips in 2000 to collect surface water samples upgradient and downgradient of the LTU.  The analysis included basic field parameters including specific conductivity.  The surface water upgradient and downgradient of the LTU was found to have a high specific conductivity.  The Department believes that saline-seeps, not related to activities at the LTU, are likely contributing to the high specific conductivity.

The Department believes the ConocoPhillips LTU is not negatively impacting groundwater or surface water.  The Department’s conclusion is based on the many years of groundwater and surface water sampling results.



Corrective action pursuant to 40 CFR 264.101 has not been required for this facility because no releases of hazardous waste or hazardous constituents have occurred that have not been promptly cleaned-up.



DEQ Contact: 
Denise A. Kirkpatrick, Solid & Hazardous Waste Specialist
Montana Department of Environmental Quality
Waste & Underground Tank Management Bureau
P.O. Box 200901
Helena, Montana 59620-0901
e-mail: dkirkpatrick@mt.gov