Petition for Exclusion of a 

Hazardous Waste  

Pursuant to 40 CFR 260.20 and 260.22 

Billings Refinery 

401 South 23rd Street 

Billings, Montana 59101 

December 2010 
Introduction 

The ConocoPhillips Billings, Montana Refinery (the Refinery) is petitioning the U.S. Environmental 

Protection Agency (U.S. EPA), Region 8 to exclude from hazardous regulation (delist) residual solids 

from processing the sludge removed from two storm water tanks. This sludge is processed via centrifuge 

and/or filter press for oil recovery and dewatering. The residual solids from the oil-recovery process may 

or may not be characterized as F037; however, taking a conservative approach and for the purposes of this 

petition they are characterized as F037, a hazardous waste under the Resource Conservation and 

Recovery Act (RCRA). The subject waste of this delisting petition is the residual solids resulting from 

processing, via filter press or centrifuge, the sludge from the two storm water tanks. 

This delisting petition includes all information necessary for the U.S. EPA, Region 8 to review the 

Refinery’s request. Primarily, a delisting petition framework is included as Attachment A. 

Sample Collection and Analysis 

To support this proposed action, the Refinery has conducted an approved sampling and analysis program 

to generate analytical data representative of the residual solids from processing the sludge removed from 

the two storm water tanks. This program included collecting sample sludge from sixteen (16) locations in 

each tank, compositing the sludge, dewatering/oil recovery via filter press, and submission of the residual 

material for analysis. ConocoPhillips believes the analytical results from this program fully characterize 

the petitioned waste including any spatial and/or temporal variability that may exist. 

Prior to sample collection, a Sampling and Analysis Plan (SAP) was prepared and submitted to the U.S. 

EPA, Region 8 for review on February 2, 2010. In response to U.S. EPA, Region 8 review comments, the 

SAP was revised and re-submitted to the U.S. EPA, Region 8 on June 8, 2010. U.S. EPA, Region 8 

personnel advised Refinery personnel on June 17, 2010 that the SAP was approved. The SAP is included 

as Attachment D of this document. 

Once the SAP was finalized, the Refinery contracted with Tetra Tech in Billings, Montana for actual 

sample collection. Tetra Tech personnel were briefed on procedures and requirements of the SAP prior to 

sample collection. Additionally, the Refinery contracted with ALS Laboratory Group in Houston, Texas 

for sample analysis. ALS personnel were also briefed prior to sample analysis regarding the SAP 

(especially the requirements for modified Toxicity Characteristic Leaching Procedure [TCLP] extraction 

fluids). Resumes for personnel involved in this effort are included as Attachment E to this document. 

Samples were collected on July 1 and 2, 2010 and submitted to the laboratory for analysis. Analytical 

data packages and a data evaluation report are presented in Attachment F. Tabulated analytical results 

can be found in Attachment C. 

Delisting Risk Assessment Software 

Analytical results were entered into Delisting Risk Assessment Software (Version 3.0.34, U.S. EPA 

Region 6) (DRAS) to evaluate the acceptability of the petitioned waste to be disposed in a Subtitle D 

landfill and to assist in determining the appropriate volume of material for which to petition. DRAS 

output tables are presented as Attachment H. 

Results of Analyses 

According to 40 CFR Sections 260.20 and 260.22, petitions for delisting must demonstrate that: 
1. The petitioned waste does not meet any of the criteria for which the waste was listed 

2. The petitioned waste does not exhibit hazardous characteristics 

3. The petitioned waste does not contain any other toxicants at hazardous levels 

Basis for Listing – Per the information contained in 40 CFR 461, Appendix VII, the basis for listing F037 

waste is the presence of benzene, benzo(a)pyrene, chrysene, lead, and chromium. While each of these 

analytes was detected in the samples collected, none of the detected concentrations exceeds the maximum 

allowable total or TCLP concentrations determined via DRAS. 

Table A. Comparison of Total and TCLP Results to Basis for Listing Analytes 

Analyte 

Maximum 

Detected Total 

Concentration 

(mg/kg) 

DRAS Maximum 

Allowable Total 

Concentration 

(mg/kg) 

Maximum 

Detected TCLP 

Concentration 

(mg/L) 

DRAS Maximum 

Allowable TCLP 

Concentration 

(mg/L) 

Benzene 0.031 -- ND (0.01) 2.75 

Benzo(a)pyrene 1.5 220 ND (0.0006) 939 

Chrysene 4.2 291,000 ND (0.0008) 250 

Lead 43.1 -- 0.00535 18.7 

Chromium 152 197,000 ND (0.006) 63.8 

ND Not Detected 

-- DRAS maximum Allowable Concentration is greater than one million parts per million. 

Hazardous Characteristics – Reactive cyanide and reactive sulfide were not detected in any sample. All 

samples were negative for ignitability. Values for pH are between 2 and 12.5 standard units. No values 

exceeded the corresponding toxicity levels. TCLP results are presented in the following table: 

Table B. Results for Toxicity Characteristic Analytes 

Analyte 

Maximum Detected 

TCLP Concentration 

(mg/L) 

Regulatory Level 

(mg/L) 

Arsenic 0.157 5 

Barium 1.12 100 

Benzene ND (0.01) 0.5 

Cadmium ND (0.006) 1 

Chlorobenzene ND (0.01) 100 

Chloroform ND (0.01) 6 

Chromium ND (0.006) 5 

o-Cresol ND (0.001) 200 

m-/p-Cresol 0.024 200 

1,4-Dichlorobenzene ND (0.01) 7.5 

1,2-Dichloroethane ND (0.01) 0.5 

1,1-Dichloroethene ND (0.01) 0.7 

2,4-Dinitrotoluene ND (0.001) 0.13 

Lead 0.00535 5 

Mercury ND (0.000042) 0.2 

Methyl ethyl ketone ND (0.02) 200 

Nitrobenzene ND (0.0008) 2 
Table B. Results for Toxicity Characteristic Analytes (continued) 

Analyte 

Maximum Detected 

TCLP Concentration 

(mg/L) 

Regulatory Level 

(mg/L) 

Pyridine ND (0.002) 5 

Selenium 0.18 1 

Silver ND (0.007) 5 

Tetrachloroethene ND (0.012) 0.7 

Trichloroethene ND (0.01) 0.5 

ND Not Detected 

Other Toxicants at Hazardous Levels – As noted in Attachment H, no other analytical result exceeds 

delisting limits. 

Delisting Request 

The Billings Refinery is requesting an exclusion from the definition of a hazardous waste of an annual 

maximum of 200 cubic yards of residual solids (from processing the sludge from the two storm water 

tanks via filter press or centrifuge) for disposal in a Subtitle D Landfill. Based on the analytical results 

contained in this petition, DRAS results, and to ensure that the waste does not pose a threat to human 

health or the environment, the Refinery proposes that four composite samples and one duplicate sample 

be analyzed as confirmation samples during each storm water tank clean-out event. These composite 

samples will be collected per the requirements of the attached Quality Assurance Project Plan 

(Attachment G) and will be comprised of filter-pressed material stored in roll-off containers during the 

clean out process. The composite samples will be analyzed for the constituents presented in the following 

table (i.e., constituents detected in analyses included in this petition): 

Table C. Maximum Concentrations for Delisting 

Analyte 

Maximum Total 

Concentration (mg/kg) 

Maximum TCLP 

Concentration (mg/L) 

Cyanide -- 110 

Antimony -- 3.83 

Arsenic 54,100 0.301 

Barium -- 1,280 

Cadmium 204,000 3.25 

Chromium 197,000 63.8 

Cobalt 262,000 7.34 

Lead -- 18.7 

Mercury 72.6 2.42 

Nickel -- 480 

Selenium -- 31 

Silver -- 242 

Vanadium -- 117 

 
Table C. Maximum Concentrations for Delisting (continued) 

Analyte 

Maximum Total 

Concentration (mg/kg) 

Maximum TCLP 

Concentration (mg/L) 

Zinc -- 7,230 

2-Methylphenol -- 103 

3&4-Methylphenol -- 1,030 

Phenol -- 6,190 

Acenaphthene -- 379 

Anthracene -- 924 

Benzo(a)anthracene 2,970 2.5 

Benzo(a)pyrene 220 939 

Benzo(b)fluoranthene 1,730 7,990 

Benzo(k)fluoranthene 20,500 -- 

Chrysene 291,000 250 

Dibenz(a,h)anthracene 232 -- 

Fluoranthene 745,000 87.8 

Fluorene -- 175 

Indeno(1,2,3-cd)pyrene 5,470 -- 

Naphthalene -- 1.17 

Pyrene -- 159 

2-Butanone -- 12,400 

Benzene -- 2.75 

Carbon disulfide -- 2,010 

Ethylbenzene -- 387 

Tetrachloroethene 75,800 0.729 

Toluene -- 539 

Trichloroethene -- 2.76 

Xylenes, total -- 341 

-- DRAS Maximum Allowable Concentration is greater than one million parts per 

million. 

Note: Di-n-octyl phthalate, phenanthrene, and bis(2-ethylhexyl) phthalate were 

detected in the analyses included in this petition; however, maximum concentrations are 

listed as “Not Applicable” for phenanthrene while both maximum concentrations are 

greater than one million parts per million for di-n-octyl phthalate and bis(2-ethylhexyl) 

phthalate in the DRAS output. 

Reported concentrations in the composite sample that are less than the listed maximum value will provide 

confirmation that the waste does not pose a threat to human health or the environment.