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To: Petroleum Refineries Docket EPA-HQ-OAR-2010-0682 

From: Chris Sarsony, EPA/OAQPS/ATAG 

Re: Environmental Screening Results for Petroleum Refineries Source Category 

Date: October 22, 2014 

This memo to the docket provides additional information regarding an interim calculation that is 

part of the environmental screening assessment for the Petroleum Refinery source category. This 

is an update providing a more complete description of the tiering methodology provided in 

Docket Item EPA-HQ-2010-0682-0485. The information in this memo does not alter the 

conclusions of the environmental risk screening assessment. The information is provided per a 

request from a commenter. 

As part of the risk assessment for the petroleum refineries source category, we conducted a 

screening-level evaluation of the potential for adverse environmental risks associated with 

emissions of the following environmental HAP: lead, mercury, cadmium, PAHs, dioxins, 

hydrogen chloride and hydrogen fluoride. The screening-level evaluation for mercury, cadmium, 

PAHs, and dioxins includes two tiers, and if modeled concentrations do not exceed available 

benchmarks in Tier I, we consider the emissions from the facility to be below the level that might 

cause an adverse environmental effect. If modeled concentrations exceed benchmarks in Tier I, 

we conduct a Tier II screen that includes less-conservative, site-specific data for several key 

parameters. For refineries, we identified four facilities that exceeded a benchmark in Tier I, and 

we therefore conducted a Tier II screen. The results of the environmental screening analysis are 

summarized in Table 1 (this table also appears as Table 3.2-6 in Section 3.2 of the May 2014 

“Draft Residual Risk Assessment for the Petroleum Refining Source Sector” hereafter referred to 

as the “draft risk report”). 

In the Tier I screening analysis, modeled concentrations for four facilities exceeded sediment 

benchmarks for PAH and one facility exceeded a soil benchmark for HgCl2. For the facilities 

that exceeded the Tier I benchmarks, we conducted a Tier II assessment. In the Tier II screening 
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analysis for PB-HAP none of the individual modeled concentrations for any facility in the source 

category exceeded any of the ecological benchmarks (either the LOAEL or NOAEL). As 

explained in section III.A.5 of the preamble to the proposed rule, our screening analysis for lead 

examined whether there were any estimated exceedances of the secondary lead NAAQS and we 

determined that there were none. The facility specific environmental risk screening results for 

PB-HAP based on actual emissions are shown in Table 2. As noted in Section 3.2 of the draft 

risk report, there were no exceedances of the acid gas benchmarks. 

After completion of the draft risk report, we determined that HgCl2 was not emitted from the 

facility that had the modeled exceedance of the soil benchmark (NEI 46556), and therefore, 

HgCl2 emissions were included in the environmental screening analysis for that facility in error. 

Correcting this error to exclude emissions of HgCl2 for this facility results in no predicted 

exceedance of the soil benchmark for HgCl2 under the Tier 1 analysis. Table 1 below differs 

from Table 1 in the draft risk report in that it reflects this correction. This correction does not 

alter the conclusions of the environmental screening assessment as presented in the draft risk 

report; rather, with the correction this facility screens out at the Tier I level instead of the Tier II 

level as is presented in the draft risk report. 

Table 1. Summary of Environmental Risk Screen Results for the Petroleum Refineries 

Source Category 

Environmental 

HAP 

Number of Facilities In Category 

Exceeding 

Percent of Modeled 

Area in Category 

Exceeding2

Tier I Screen Tier II Screen1

NOAEL LOAEL NOAEL LOAEL NOAEL LOAEL

PBHAP 

Pb None None None None 0% 0% 

HgCl2 NA None3 None None 0% 0% 

Cd None None None None 0% 0% 

PAH 4 None None None 0% 0% 

Dioxin None None None None 0% 0% 

Acid 

Gases 

HF4 NA None - - NA 0% 

HCL5 NA None - - NA 0% 

NA – Not Applicable. 

1- Tier II screen is performed for PB-HAP when there are exceedances of the Tier I screen. The acid gas 

screen is a one tier screen. 
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2 - A value of 0% indicates that none of the modeled data points exceeded the benchmark or the area 

exceeded is less than 0.5 percent. For PB-HAP the percent area is based on the Tier II results, if a Tier II 

analysis is performed. Otherwise, the percent area is based on the Tier I results. 

3 – After completion of the draft risk report, it was determined that the facility that exceeded the soil 

benchmark as part of the Tier I analysis (NEI 46556) did not emit HgCl2. Correcting our analysis to 

exclude modeled HgCl2 emissions for this facility results in no Tier I exceedances for HgCl2. 

4 – For HF, we evaluated two benchmarks, one from Canada and the other from the State of Washington. 

Although, they are both considered to be LOELs - the level between a NOAEL and a LOAEL, we have 

listed the results under the LOAEL column. 

5 – For HCL, we evaluated one benchmark at the LOAEL level. 
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Table 2 – Environmental Screening Results for Facilities with Tier I Exceedances for PB-H

(Based on Actual Emissions) 

a – The number of times the media concentration exceeds the benchmark. 

Facility NEI ID Environmental HAP Assessment Endpoint Benchmark Effects Level T

NEI6087 - Marathon Petroleum Company LP 

Garyville, LA PAH Sediment Community No-effect Level 

NEI12988 - Phillips 66 

Ponca City, OK PAH Sediment Community No-effect Level 

NEI34050 - Northern Tier Energy LLC 

St. Paul Park, MN PAH Sediment Community No-effect Level 

NEI41591 - Valero Refining Company - 

Tennessee, L.L.C., a Delaware limited liability 

company 

Memphis, TN 

PAH Sediment Community No-effect Level