### Addition of a Subsurface Intrusion (SsI) Component to the Hazard Ranking System (HRS)

Regulatory Impact Analysis

### T ABLE OF CONTENTS

Executive Summary

................................................................................................ ....................................... ES -1

1. Introduction ................................................................................................................................................. 1

1.1. Backgroun d ........................................................................................................................................... 1

1.2. Need for Regulatory Action on HRS Rule ........................................................................................... 2

1.3. Summary of Proposed Rule .................................................................................................................. 3

1.4. Alternative Regulatory Options ............................................................................................................ 6

1.5. Scope of Analysis ................................................................................................................................. 7

1.6. Organization of Document.................................................................................................................. 10

2. Sites Affected by the Proposed Rule ......................................................................................................... 11

3. Impacts of the Proposed Rule .................................................................................................................... 14

3.1. Introduction ......................................................................................................................................... 14

3.2. Cost Estimation Methodology ............................................................................................................ 14

3.3. Cost Estimates .................................................................................................................................... 21

3.4. Summary of Costs ............................................................................................................................... 24

3.5. Benefits ............................................................................................................................................... 24

3.6. Caveats and Limitations ...................................................................................................................... 25

4. Distributional Impacts and Considerations ................................................................................................ 26

4.1. Executive Order 12866 – Regulatory Planning and Review, and Executive Order 1 3563 – Improving Regulation and Regulatory Review ............................................................................................................... 26

4.2. Executive Order 12580 – Superfund Implementation ........................................................................ 27

4.3. Executive Order 12898 – Environmental Justice ................................................................................ 28

4.4. Executive Order 13045 – Protection of Children from Environmental Health Risks & Safety Risks 31

4.5. Executive Order 13132 – Federalism ................................................................................................. 32

4.6. Executive O rder 13175 – Consultation and Coordination With Indian Tribal Governments ............. 32

4.7. Executive Order 13211 – Actions that Significantly Affect Energy Supply, Distribution, or Usage . 32

4.8. Paperwork Reduction Act ................................................................................................................... 33

4.9. R egulatory Flexibility Act .................................................................................................................. 33

4.10. U nfunded Mandates Reform Act ........................................................................................................ 34

4.11. National Technology Transfer and Advancement Act ....................................................................... 34

5. Summary of Costs, Benefits and Other Impacts ........................................................................................ 35

5.1. Cost Benefit Comparison .................................................................................................................... 35

### 5.2. Other Required Analyses .................................................................................................................... 36

APPENDIX A: Options Selection Matrix

APPENDIX B: Conceptual Site Model Used to Estimate Costs of Screening for Subsurface Intrusion
Contamination

APPENDIX C: Detailed Methodology for Estimating Impacts on Mino rity and Low-Income Populations

APPENDIX D: Costs for Vapor Intrusion Site Inspection Tasks Compiled for Regulatory Impact Analysis

### ES

- 1 

### Executive Summar y

This regulatory impact analysis (RIA) document presents an analysis of the costs, benefits and economic impacts of the proposed amendment to the Hazard Ranking System (HRS) regarding identification of releases and
threatened releases of hazardous substan ces , pollutants, or contaminants 1



### . The proposed rulemaking will add a

s ubsurface intrusion ( SsI ) component to the existing s oil exposure pathway of the U.S. Environmental Protection Agency’s ( EPA ) HRS . The HRS is the primary method EPA uses to identify the sites posing the greatest threat nationally for listing on the Superfund National Priorities List (NPL) under the Comprehensive Environmental Response, Compensation, and Liabilit y Act ( CERCLA ) and the Superfund Amendments and Reauthor ization Act (SARA). Th e economic assessment included in this analysis quantifies the expected cost impacts of the proposed action, in accordance with the requirements of Executive Order 12866 and Office of Management and Budget ( OMB ) Circular A -4. 2 

### The ana lysis characterize s the expected benefits of the rule and satisfies other administrative requirements established by statute or executive order.

Overview

CERCLA was passed in Congress in 1980 and amended by SARA in 1986 in response to environmental and public health concerns over uncontrolled hazardous waste sites. CERCLA, as amended by SARA, established the Superfund program to respond to releases and threatened releases of hazardous substances. CERCLA Section 105 requires EPA to establish criteria for d etermining priorities among releases or threatened releases of hazardous substances for the purpose of taking remedial action.

Pursuant to section 105 of CERCLA, EPA established the HRS as a tool to identify and prioritize sites posing the
most immediate and serious potential threats to human health and the environment. As originally promulgated (47 FR 31180), the HRS evaluated sites based on three scoring pathways: ground water, surface water and air. The HRS was amended in 1990 (55 FR 51532) to include a soil exposure pathway. The HRS site score, which ranges from 0 to 100, is obtained by combining the scores of all pathways examined at a given site. A site receiving a score of 28.50 or higher is eligible for placement on the National Priorities List (NPL ), where it is targeted for further investigation and possible site remediation. Since the inception of the HRS in 1982, more than 1,7 00 sites have been placed on the NPL.

EPA is now considering amending the HRS again to include consideration of subsurface intrusion. Subsurface intrusion is an issue at sites with subsurface contamination, where chemical contaminants (especially volatile substances) can enter into overlying stru ctures. These contaminants can form vapors, which can pose a threat to individuals primarily through inhalation, but also through dermal contact, ingestion and fire or explosion hazards when concentrated. Currently, there is no mechanism in the HRS for eva luating threats to human health posed by subsurface intrusion. The existing pathways do not evaluate indoor air and site

- related contaminants that may release vapors.

T o implement the addition of an SsI contamination component to the HRS

, EPA is considering amending the

regu lations at Title 40 of the Code of F ederal Regulations (CFR) 300.425. The a gency believes that including the
evaluation of SsI contamination in the HRS serves the public interest by widening the scope of evaluation of

1 For the purpose of this regulatory impact analysis, the term “hazardous substances, pollutants or contaminants” will be refer red to simply as “hazardous

substances.”

2 Executive Order 12866, Regulatory Planning and Review, October 4, 1993; Office of Management and Budget, Circular A

- 4, September 17, 2003.

### ES

- 2 

### human and environme ntal health issues posed by Superfund sites. C onsideration of SsI threat s will enable EPA to meet the Congressional mandate to assess the relative degree of risk posed to human health and the environment by an actual or potential release of hazardous subst ances into the environment. EPA considers the addition of an
SsI component to the HRS to be consistent with CERCLA Section 105 and SARA because it will improve the agency’s ability to identify sites warranting further evaluation. Consideration of SsI threa ts also will enable EPA to address risks posed by subsurface intrusion of contaminants into occupied structures for all populations who live and work in areas where releases to the subsurface may create exposures.

Scope of the Effects of the Proposed Rule

Contaminated sites are evaluated through EPA’s Site Assessment program to determine their potential to be added to the NPL. The evaluation of sites involves a series of initial, limited site investigations and data collection efforts related to site conditions. This process is implemented by the EPA regional site assessment programs. Investigations often include a Preliminary Assessment, Site Inspection (SI) , and related investigations. The HRS
evaluation uses the information obtained from these initia l, limited investigations to rank sites according to the risk they may pose, relative to other sites, and determine if further investigation is warranted through the Remedial or Removal programs.

Each EPA region has a set budget for conducting site assessm ents. The sites in each EPA region of the country are reviewed to determine those that pose the highest risk and are prioritized accordingly. The addition of an SsI component to the HRS is not expected to result in additional site assessment funding to acc ount for any increase in site assessment costs. Instead, the pipeline of sites will continue to be reviewed under the site assessment process. If it is found that SsI- contaminated sites potentially pose a greater risk than other sites, then these sites
wil l be prioritized over other sites with contamination not resulting from SsI.

The proposed rule will affect how EPA and its State Cooperative Agreement partners conduct site assessments and HRS scoring. The proposed rule does not impose direct economic or cost impacts on any private entity because the HRS is a screening tool that does not impose regulatory requirements on any non

- governmental entity. The CERCLA site assessment program is operated strictly by the public sector using funds that are appropriated annually and reside in the Superfund Trust Fund. State and tribal partners may receive financial
assistance from EPA to evaluate sites through a Cooperative Agreement. EPA and states or tribes collaborate closely throughout the Cooperative Agreement pro cess, particularly when identifying sites to be evaluated and establishing priorities for performing evaluations. As necessary, sites where subsurface intrusion threats exist may then be evaluated using the HRS and, if warranted, proposed for placement on the NPL. Given the current budget climate, EPA does not expect that there will be additional funds made available to condu ct additional site

assessments. Because SsI sites have the potential to pose a high level of risk to residents and occupants of other buildings in their vicinity, EPA expects that there will be a realignment and reprioritization of its internal resources and state Cooperative Agreement funding to address SsI sites. Therefore, EPA will develop a strategy to assess SsI sites in a timely manner, while balancing other site assessment needs. For these reasons, EPA believes that this proposed rule will not result in the listing of more sites on the NPL during any particular interval. In order to better understand the potential size of the repri oritization the analysis estimates the costs nationally that

EPA and its partners might divert from other resources in order to conduct SsI evaluations.

The proposed addition may increase the costs to government agencies conducting assessments at SsI sites because the scope of a typical SI may need to be expanded or may require more expensive sampling to collect information for an SsI evaluation. SsI sampling may require additional sampling and different sample types than those

### ES

- 3 

### collected at other site s. This may result in an increase in some site assessment costs at some sites with possible SsI issues. However, SsI site assessment costs at some other sites may be comparable to, or even less than, sites scored under the existing HRS. For example, a site assessment requiring sampling of deep ground water monitoring wells under the existing HRS may cost as much as, or more, than sampling conducted at sites with possible SsI issues. Additionally, any newly increased costs to government agencies conducting a ssessments at SsI sites are expected to be minimal because federal agencies should already be identifying and addressing SsI as part of their environmental programs.

However, a s stated above, no other authority consistently and comprehensively addresses SsI contamination across all potential sites, particularly when SsI is the key exposure pathway. While most states have identified SsI sites as a high priority, not all states have SsI programs, and states with programs vary in their authority, resources
and remediation criteria. A redirection of resources available to the states through Cooperative Agreeme nt funding is expected to provide for greater national consistency in the identification and evaluation of SsI sites. Additionally, EPA issue d new vapor i ntrusion guidance in June 2015, OSWER Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air . Together with this proposed rule, EPA will provide a comprehensive framework to guide evaluation of SsI sites across the country.

Proposed Regulatory Changes

The proposed addition of an SsI component to the HRS soil exposure pathway would be used by EPA and organizations performing work on behalf of EPA (state and tribal partners) to evaluate sites whe re SsI contamination may be a concern . Through this proposed rulemaking, EPA would revise the HRS and its process for evaluating four pathways. EPA is considering various options for incorporating an SsI screening process into the existing HRS without alte ring the existing HRS structure and methodologies.

This analysis considers the economic impacts of three regulatory options that vary in how a site with a potential
SsI threat will be scored using the HRS:

• 

### O ption 1 – Score only populations and regularly occupied structures with in a zone defined by observed exposures above background and resulting from subsurface intrusion attributable to the site being
evaluated . Under this option, scoring will include both actual contamination for sampled structures and
inferred contamination for regularly occupied structures within the Area of Observed Exposure (AOE). The AOE is bounded by structures with documented contamination resulting from subsurface intrusion attributable to the site being evaluated

.

• 

### Option 2 (the preferred option) – Score only populations and regularly occupied structures with in zones with actual exposure , as well as those above demonstrated subsurface contamination. Under this option, a site’s score will include actual contamination for sampl ed structures and inferred contamination both for regularly occupied structures in the AOE and for regularly occupied structures in the Area of Subsurface
Contamination (ASC). The ASC is defined as an area outside of the AOE by sampling locations with documented contamination significantly above background and the significant increase can be attributed

, at least in part

, to the site being evaluated (e.g., ground water and soil gas sampling points).

• 

### Option 3 –Score all populations in zones with actual or potential exposure. Under this option, in addition to actual contamination for sampled structures and inferred contamination for regularly occupied structures in the AOE and the ASC, a site’s score will include potential future contamination for regularly occupied structures in the Potential Ground Water Migration Zone (PMZ). The PMZ is defined as an

### ES

- 4 

### area between the ASC and a target distance limit encompassing the potential area where the ground water or soil gas contamination plume may migrate in the futu re.

The three regulatory options are summarized and compared in Exhibit ES-1.

### ES -5 EXHIBIT ES

- 1. OPTIONS CONSIDERED FOR THE PROPOSED R ULE

OPTION FOR SCORING P OPULATIONS POTENTIAL

NUMBER OF

INTRUSION SITES

ASSESSED POTENTIAL

NUMBER OF NPL

CALIBER

INTRUSION SITES PROS/CONS CONSISTENCY WITH OTH ER HRS PATHWAYS

Option 1

– Consider Only Actual and Inferred Exposures

• Includes all actual and inferred

contamination for regularly occupied structures within the Area of Observed Exposure (AO E )

• Does not include potential exposure for

regularly occupied structures outside the AO E Less Least Pro: Will have a high probability that identified releases pose a risk when scoring by zones of contamination

Con: Could fail to identify sites warranting placement on the NPL because potential exposures will not be considered; does not consider future condit ions/migration and may necessitate greater review of sites given a “no further action” designation Option is consistent with:

• The soil exposure pathway in that it

does not consider potential targets and infers Level II contamination

• All pathways in how Lev el I and II

targets are weighted

Option 2 (Preferred Option)

– Consider Actual , Inferred and Probable Exposures

• Includes those regularly occupied

structures within the AO E and the Area of Subsurface Contamination ( AS C)

• Includes both actual contamination

intrusion and probable exposure to subsurface contamination for regularly occupied structures within the AO E and AS

C Less Middle Pro : Would ensure that most releases posing a significant risk are identified by relying up on lines of evidence

Con : Could lead to an underestimate of the number of releases because future migration of subsurface contamination is not accounted for and/or because lines of evidence gathered during the Site Assessment process may be incomplete ; does not consider future conditions/migration and may necessitate greater review of sites given a “no further action” designation Option is consistent with:

• The soil exposure pathway in that there

is no inference of contamination for Level I targets

• The soil exposure, air and surface water

pathways in that there is inference of contamination for Level II targets

• The air pathway in that on

- source

targets are weighted (partially consistent – weighting values are different)

• All pathways in how Level I and II

t argets are weighted

### ES

- 6 OPTION FOR SCORING P OPULATIONS POTENTIAL

NUMBER OF

INTRUSION SITES

ASSESSED POTENTIAL

NUMBER OF NPL

CALIBER

INTRUSION SITES PROS/CONS CONSISTENCY WITH OTH ER HRS PATHWAYS

Option 3 – Consider Actual

, Inferred, Probable and Potential Exposures

• Inclu des regularly occupied structures

within the AO E , the ASC and the Potential Ground Water Migration Zone (PMZ)

• Includes actual contamination intrusion,

probable and potential exposure to subsurface contamination for structures within the AO E

, AS C and PMZ

• Includes unsampled structures, but are

considered to be potentially exposed More Most Pro: Would ensure that all releases posing a risk are identified

Con: C ould result in identification of low risk releases because not all identified releases will result in future
exposure ; limited rationale for projecting extent of PMZ; not assuming migration in all directions (i.e., <360 degrees) could result in quest ioning the target delineation for ground water and air pathways Option is consistent with:

• The air pathway in that there 2

different weightings for potential targets

• The air pathway in that on

- source

targets are weighted (partially consistent – weighting v alues are different)

• The ground water pathway in that the

same weighting values are used

• All pathways in how Level I and II

targets are weighted

### ES -7 A ssessment of Costs and Benefits

The analysis estimates costs of implementing the proposed rule. These costs include the cost of investigating SsI at sites with probable SsI issues and the additional administrative cost of preparing HRS packages for sites that score 28.50 or higher due in part to SsI contamination. The analysis also qualitatively discusses the benefits of the proposed rulemaking, which include improved quality of information and more effective prioritization of remedial efforts by the Superfund program through a more compr ehensive characterization of sites with SsI threats. Although listing a site on the NPL may potentially lead to site remedia tion and potential improvements to human health, any such health benefits are realized at a later point in the Superfund process and are removed from the HRS scoring process. 3 

### Simply scoring a site with the HRS does not necessitate an improvement in human health. Therefore, any health benefits resultant from remediation of a site are contingent impacts and are not direct impacts of con ducting an HRS evaluation.

Affected Sites: To support the proposed rulemaking

, EPA conducted a screening

- level assessment of sites with potential or identified SsI threats. As a first step in collecting the list of sites potentially affected by the propos ed rule, EPA consulted with site assessment experts that work in Superfund and other federal programs, including Brownfields, Resource Conservation and Recovery Ac t and other Federal/state programs. These experts used their professional knowledge and famil iarity with their programs’ historical data to identify potential site candidates.

EPA also asked for input from state counterparts, in particular state programs that were known to have taken a more thorough review of the SsI pathway at sites. Through this process, EPA identified approximately 1,073 sites

as potentially affected by the proposed rulemaking at the time of this analysis. These sites are not currently on the NPL, and all have a potential or identified SsI threat. Within the group of sites potentially affected by the proposed rule, EPA defined four categories:

1. Tier 4: Sites identified as having a suspected SsI threat based on EPA’s Superfund database and Agency for Toxic Substances and Disease Registry keyw ord searches , as well as EPA or state self

- identification

, but for which no sampling data were obtained ;

2. Tier 3: Sites identified a s having characteristics or evidence that indicate SsI may have occurred or will

occur;

3. Tier 2: Sites identified as having an SsI threat documented by subslab, crawl space, or indoor air samples, but insufficient HRS -required evaluation factors to qualify for the NPL; and

4. Tier 1: Sites identified as having an SsI threat with documented actual exposure of a sufficient number of targets with enough other HRS- required evaluation factors to suggest the site may qualify for the NPL

.
Unit Costs: EPA used data from the Superfund Enterprise Management System (SEMS) during the 5- year period
of FY 2011 through FY 2015 to estimate the typical number of sites assessed each year

. EPA also developed a conceptual site model of a site with an SsI threat to identify unit costs associated with investigating a site with suspected SsI contamination as part of the HRS. 4

3 Later remedial decisions that consider information collected under the proposed addition could separately have specific healt h benefits (e.g., reducing human exposure to hazardous substances), but these impacts are contingent upon a series of separate and often non

- sequential actions that occur after listing a site on the NPL. The addition of subsurface intrusion to the HRS is several regulatory steps removed from realizing health benefits and therefore outside the scope of this regulatory impact analysis.

4 Superfund Enterprise Management System (SEMS) Accomplishment Reports data provided by Randy Hippen, EPA Office of Superfund Remediation and

Technology Innovation (OSRTI), on October 30, 2015. The nu mber of annual sites assessed between FY2011 and FY2015 ranged from 171 to 242. For purposes of this analysis a baseline of 200 assessments was selected as it was consistent with previous program activity. The EPA Superfund program is in the final
stages o f replacing the Comprehensive Environmental Response Compensation and Liability Act Information System (CERCLIS) data managem ent system for

### ES -8 Exhibit ES

- 2 identifies t he numbers of sites evaluated and unit costs for the baseline and each regulatory scenario. In all scenarios, the analysis assumes that the program typically conducts assessments at approximately 2 00 sites per year, and typically prepares 20 HRS packages per yearat a cost of $65,000 per package. 5 

### In t he baseline scenario, all site assessments and HRS packages involve non

- SsI sites. In the regulatory scenarios, the analysis assumes that some assessments and HRS packages would involve sites with SsI contami nation replacing non

- SsI
sites. Site assessment unit costs for SsI sites incorporate the additional site inspection costs associated with investigating SsI threats

. 6

EXHIBIT ES

- 2. UNIT VALUES USED TO ESTIMATE COST IMP ACTS OF THE HRS SSI ADDITION UNDER THREE

REGULATORY OPTIONS

BASELINE OPTION 1 OPTION 2 OPTION 3

Sites Assessed per Year

N on

- SsI Sites 200 180 180 160

SsI Sites 0 20 20 40

Total Sites 2 00 200 200 200

HRS Package s per Year

N on

- SsI Sites 20 19 18 16

SsI Sites 0 1 2 4

Total Package s 20 20 20 20

Average Cost per Non

- SsI Site Assessed $ 58,400 $ 58,400 $ 58,400 $ 58,400

Average Cost per SsI Site Assessed

High End n/a $ 107,000 $1 28,000 $1 32,000

Best Estimate n/a $ 80,900 $ 94,000 $ 97,800

Average Cost per HRS Package $65,000 $65,000 $65,000 $65,000



### Total Costs and Benefits: The results of the analysis of the costs and benefits of the proposed rule are summarized in Exhibit ES-3. Total annual costs under Option 2 (the preferred option) are expected to range from $0.7 million to $1.4 million. Total annual costs in all scenarios are less than $ 3 million.

The RIA does not provide a quantitative estimate of benefits of the proposed rule . B enefits of the rule are expected to be minimal, because the rul e will not directly require actions that reduce risks

. Any risk reduction that may result from the proposed action would come from future site- specific regulatory actions. However

, qualitative benefits of this proposed action include improved quality of information and more e ffective

Superfund site information, with the Superfund Enterprise Management System (SEMS) (hereinafter referred to intercha ngeably with the term EPA’s Superfund database).

5 The number and cost of HRS packages are based on data collected in support of Information Collection Request (ICR) 1488.08, p rovided by Randy Hippen, EPA

Office of Superfund Remediation and Technology Inno vation (OSRTI), on June 7, 2011

.

6 While the analysis portrays the various options as though they will result in additional expenditures for site assessments and HRS package preparations, in the

context of a fixed site assessment budget, it is likely that the cost impacts of the proposed rule would manifest in a reduction in site assessment activity.

### ES -9 prioritization of remedial efforts by the Superfund program through a more comprehensive characterization of sites with SsI threats. For example, this proposed action could facilitate immediate r emoval a ctions if an early SsI investigation uncover s a significant threat.

Caveats and Limitations: Due to the limitations in data availability and uncertainties inherent in trying to predict future site assessment activities, this cost analysis made several simplifying assumptions in the development of a reasonable cost estimate for this proposed action. For example, the analysis did not consider whether the costs for investigating the SsI threat could be lower if other pathways (e.g., ground water) were investigated at the same time or if a pathway threat no longer needed to be investigated. Additionally, due to the ranges of cost estimates provided by data sources for SsI- related investigative activities, the analysis only estimated cost estimates using median and maximum task unit costs. Therefore, the a nalysis does not consider the possibility that future costs to investigate the SsI threat could be less than the median costs (e.g., due to improved sampling methods).

The site assessment costs used in this analysis also represent a potential source of unc ertainty . Costs provided by different data sources for the same investigative task, in some cases, have a wide range in values. To account for this potential variability in costs, during the evaluation of costs associated with investigating the SsI threat using a conceptual site model, EPA decided on a case -by- case basis whether to exclude outliers from the total SI cost
estimate. For example, one dataset contained a cost estimate of $600/sample for Summa canister analysis, which appears to be an outlier on the high end . The $600 unit cost resulted in a cost of $45,600 to analyze 76 Summa canister samples (see Exhibit B -6) , which is significantly higher than other estimates

. Summary of Costs:

Presented below is an example illustrating how the high end cos t was derived for Option 1 (see Exhibit ES -3). The following formula was used to arrive at the high -end total co st of approximately $1 million for Option 1 (see Exhibit ES

- 2 for values) :

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

− AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA = AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

AAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAA ∗ = $9 72

, 000 7

7 Individual cost values were calculated using original unrounded input values; each final value presented in E xhibits ES

- 2 and ES -3 was rounded to three

significant digits.

### ES -10 EXHIBIT ES

- 3. SUMMARY OF COSTS AND B ENEFITS OF PROPOSED HRS S S I REVISION (MILLION$)

TYPE OF IMPACT OPTION 1 OPTION 2
(PREFERRED

OPTION) OPTION 3

Costs

Annual Costs of Investigating SsI threats and of Preparing HRS Packages for SsI sites ( million 2011$)

High

- End Scenario $ 1.0 $ 1.4 $ 2.9

Best

- Estimate Scenario $ 0.5 $ 0.7 $ 1.6

Benefits
Improved quality of information and more effective prioritization of remedial efforts by the Superfund program through a more comprehensive characterization of sites with SsI threats. Not quantifiable

Note : Because cost impacts are expected to be constant on an annual basis over time, presenting the net present value of costs would not add analytic value and is not presented here

. Therefore

, although alternative discount rates of seven percent and three per cent were not considered, the c osts presented in this exhibit satisfy OMB Circular A

- 4 and EPA policy requirements to annualize regulatory impacts using alternative discount rates of seven percent, three percent and zero percent (undiscounted).



### Assessment of Demographic Impacts: Although the impacts of the proposed rulemaking are limited to increased EPA costs, it is possible that information collected under this rule will contribute to separate, future decisions to propose sites with SsI contamination for listing on the NPL and to undertake remediation. Because any subsequent change in risk or cost related to SsI sites would be contingent on future regulatory actions, any change in risk or cost related to site remediation would also be “contingent” impacts. While not a direct effect of the rule, one potential contingent impact of concern to EPA is the possibility that consideration of SsI sites might
contribute to future actions that would have disproportionate impacts on minority or low- in come populations. 8 

### The analysis assesse s this possibility by examining the demographic characteristics of populations living within 1 and 3 miles of sites potentially affected by the proposed action.

The demographic analysis reveals that the areas around potentially affected sites have small but a statistically significant concentration of minority and low -income populations. In other words, the population surrounding potentially affected sites has a higher percentage of minority and low -income populations than the general population of the county in which the sites are located. This suggests that any remediation at sites associated with
SsI contamination would be likely to reduce human health risk in the context of disproportionately high minority and low-income populations. Therefore, EPA does not anticipate any disproportionate adverse effects on these communities, either as a direct or contingent impact of the proposed rule. Because SsI sites have the potential to pose a high level of risk to residents a nd occupants of other buildings in their vicinity, EPA expects that there will be a realignment and reprioritization of its internal resources to address SsI sites . If it is found that SsI

contaminated sites potentially pose a greater risk than other sites , then these sites will be prioritized over other
sites without SsI contamination

. EPA is not able to predict the location of the sites without SsI contamination or

8 In the context of this analysis, “contingent impacts” refer to impacts of the proposed rule that are dependent on other poten tial actions that might occur

outside of the proposed rule. The use of the word “contin gent” in this analysis is unrelated to the “contingent valuation” methodology that economists use to estimate the value of nonmarket goods (e.g., clean air).

### ES -11 demographic characteristics of populations living nearby. Additionally, because a precise geographic location
could not be determined for the majority of the sites (precise geographic coordinates were identified for 240 of approximately 1,073 sites), the result is an uneven distribution of sites used in the anal ysis. Additionally, to
account for the range in sizes of potential sites, as well the uncertainty related to site extent and location, the analysis uses two distance rings (1 - and 3- mile radii) for estimating affected populations near a site. EPA also conducted an analysis to determine if updated U.S. Census data would identify a reduction in the proportion of the population that is minority or below the poverty level near sites with potential SsI contamination. T he results
based on 2000 U.S. Census data

, discussed above, were compared with 2009-2013 American Community Survey
data. This analysis indicated that the proportion of the population that is minority or below the poverty level near sites with potential SsI threats did not decrease from 2000 to 2013.

### ES -12 Other Regulatory and Distributional Issues

As part of this RIA, EPA also assessed the proposed rule’s potential impacts related to a number of relevant executive orders and statutes, including the following:

• Executive Order 12866 – Regulatory Planning and Review;

• Executive Order 12898 – Environmental Justice;

• Executive Order 13045 – Protection of Children from Environmental Health Risks and Safety Risks;

• Executive Order 13132 – Federalism;

• Executive Order 13175 – Consultation and Coordination With India n Tribal Governments;

• Executive Order 13211 – Actions that Significantly Affect Energy Supply, Distribution, or Usage;

• Executive Order 13563 – Improving Regulation and Regulatory Review;

• Paperwork Reduction Act;

• Regulatory Flexibility Act;

• Unfunded Mandate s Reform Act; and

• National Technology Transfer and Advancement Act.

EPA ’s evaluation of the impacts of the proposed rule under all of these policies and statutes concludes that no significant impacts exist, due to the limited cost and narrow scope of the proposed action.

### 1 

### 1. Introduction

This document presents an analysis of the costs, benefits and economic impacts of the proposed amendment to the Hazard Ranking System (HRS) regarding identification of releases and threatened releases of hazardous substances, pollutants, or contaminants 9



### . The proposed rulemaking will add a subsurface intrusion ( SsI )
component to the existing s oil exposure pathway of the U.S. Environmental Protection Agency’s ( EPA ) HRS

. The HRS is the pr imary method EPA uses to identify the sites posing the greatest threat nationally for listing on the Superfund National Priorities List (NPL) un d er the Comprehensive Environmental Response, Compensation, and Liability Act ( CERCLA ) and the Superfund Amendments and Reauthorization Act (SARA). Th e economic

assessment in c luded in this analysis quantifies the expected cost impacts of the proposed action

, in accordance with the requirements of Executive Order 12866 and Office of Manageme nt and Budget ( OMB ) Circular A -4. 10 

### The analysis characterize s the expected benefits of the rule and satisfies other administrative requirements established by statute or executive order.

1.1. Background

CERCLA was passed in Congress in 1980 and amended by SARA in 1986 in response to environmental and public health concerns over uncontrolled hazardous waste sites. CERCLA, as amended by SARA, established the Superfund program to respond to releases and threatened releases of hazardous substances. CERCLA Secti on 105 requires EPA to establish criteria for determining priorities among releases or threatened releases of hazardous substances for the purpose of taking remedial action.

Pursuant to section 105 of CERCLA, EPA established the HRS as a tool to identify and prioritize sites posing the most immediate and serious potential threats to human health and the environment. As originally promulgated (47 FR 31180), the HRS evaluated sites based on three scoring pathways: ground water, surface water and air. The

HR S was amended in 1990 (55 FR 51532) to include a soil exposure pathway. The HRS site score, which ranges from 0 to 100, is obtained by combining the scores of all pathways examined at a given site. A site receiving a score of 28.50 or higher is eligible fo r placement on the NPL, where it is targeted for further investigation and possible site remediation. Since the inception of the HRS in 1982, more than 1,7 00 sites have been placed on the

NPL

.
EPA is now considering amending the HRS again to include consideration of s ubsurface intrusion. Subsurface intrusion is an issue at sites with subsurface contamination, where chemical contaminants (especially volatile substances) can enter into overlying stru ctures. These contaminants can form vapors, which can pose a threat to individuals primarily through inhalation, but also through dermal contact, ingestion and fire or explosion hazards when concentrated. Currently, there is no mechanism in the HRS for eva luating threats to human health posed by subsurface intrusion. The existing pathways do not evaluate indoor air and site

- related contaminants that may release vapors.

9 For the purpose of this regulatory impact analysis, the term “hazardous substances, pollutants or contaminants” will be referred to simply as “hazardous

substances.”

10 Executive Order 12866, Regulatory Planning and Review, October 4, 1993; Office of Management and Budget, Circular A

- 4, September 17, 2003

### 2 

### 1.2. Need for Regulatory Action on HRS Rule

In order to implement the addition of an SsI contamination component to the HRS

, EPA is considering amending the regulations at Title 40 of the Code of F ederal R egulations (CFR) 300.425 : Establishing remedial priorities

. The a gency believes that including the evaluation of SsI contamination in the HRS serves the public interest by widening the scope of evaluation of human health issues posed by Superfund sites. Consideration of SsI threat s will enable EPA to meet the Congressional mandate to assess the relative degree of risk posed to human health by an actual or potential release of hazardous substances into the environment. EPA considers the addition of an SsI component to the HRS to be consistent with CERCLA Section 105 and SARA because it will improve the agency’s ability to identify sites warranting further evaluation. Consideration of SsI threats also will enable EPA to address risks posed by subsurface intrusion of contaminants into occupied structures for all populations who
live and work in areas where r eleases to the subsurface may create exposures. Consideration of SsI threats will
also support accelerati on of cleanups where appropriate and return sites to productive use in a manner protective
of human health and the environment.

No mechanism for evalua t ing threats posed by SsI contamination currently exists within the HRS, and no other regulatory programs are available that consistently and permanently remediate the source of the threat posed by
SsI contamination when it is the sole exposure route.

Alternatives to Federal Regulatory Action

EPA considered, and ultimately rejected, the use of alternatives to Federal regulatory action to address the need to
evaluate SsI threats. 11 

### A critical factor in this consideration is the mandate under CERCLA Sectio n 105 that EPA implement the HRS to take into account “...to the extent possible the population at risk, the hazard potential of hazardous substances..., the potential for contamination of drinking water supplies and the potential for direct
human contact.” Du e to advances in technology since EPA last revised the HRS in 1990, SsI threats can now be evaluated comprehensively, improving the ability of EPA to prioritize releases at sites for further investigation.

EPA also considered whether existing Federal and n on- Federal programs adequately address risks associated with
SsI threats at contaminated sites. Under the existing HRS, several sites on the NPL have identified SsI

- related health risks in later stages of site remediation (e.g., during remedial design or f ive - year reviews). For this reason, and consistent with the mandate under Section 105, EPA is adding an SsI component to the HRS. Considering SsI

co ntamination in the HRS would potentially speed the identification of risk at similar sites, and could contr ibute to a reduction in human exposures through earlier remediation, and possibly at a lower cost. In addition, some
sites with SsI as the key exposure pathway may not currently score 28.50 on the HRS in spite of actual or potential human exposure.

In addition to the Superfund removal and remedial programs, SsI threats are currently addressed under the authority of several other programs, includin g Superfund enforcement actions; the Superfund Alternative Approach; Superfund Removal; R esource Conservation an d Recovery Act (RCRA) Corrective Action and RCRA
enforcement ; Brownfields; and State Superfund and voluntary cleanup programs. In addition, EPA examined the

11 The alternatives to this proposed regulatory action considered by EPA are discussed in further detail in section V.A.2 , What Alternative Regulatory Options to this Action Were Considered by EPA?, of the preamble to the SsI proposed rulemaking and section 2.1.b, Alternative Methods Co nsidered for Add ressing Subsurface Intrusion Sites, of the proposed rulemaking’s technical support document.

### 3 

### possibility of expanding use of the listing mechanism. 12 

### However, no other authority consistently and comprehensively addresses SsI contamination across all potential sites, particularly when SsI is the key exposure pathway. In particular, state programs vary significantly in addressing SsI threats . Not all sta tes have SsI programs, and states with programs var y in their authority, resources and remediation criteria.

The Interstate Technology and Regulatory Council’s Vapor Intrusion Team developed and conducted an on- line survey of state, federal and tribal age ncies regarding SsI regulations, policy and guidance. 13 

### Ninety

- six percent of survey respondents consider SsI a concern, though only eleven percent have a procedure for evaluating SsI codified into law. A majority of the states that responded to the survey expressed that their procedures for addressing vapor intrusion were only informally adopted by their agencies, with most deferring to EPA guidance.

Finally, EPA considered whether the 2002 OSWER Draft Guidance for Evaluating the Vapor Intrusion to Indoor

A ir Pathway from Groundwater and Soils (Subsurface Vapor Intrusion Guidance) , in addition to guidance published by states, might provide an alternative mechanism for addressing SsI . The available state and federal guidance provide useful tools and technique s for helping to conduct site assessments, which EPA hopes to apply in implementing this regulation. 14 

### However, they do not establish a comprehensive science and legal framework for addressing Ss I issues.

1.3. Summary of Proposed Rule

The proposed addition of an SsI component to the HRS soil exposure pathway would address sites nationwide
where SsI contamination may be a concern but the sites do not qualify for the NPL using the present HRS. Through this proposed rulemaking, EPA would augment the HRS and its process for evaluating four pathways by considering various options for incorporating an SsI screening process into the existing HRS without altering the existing HRS structure and methodologies.

The HRS is a numerically based screening tool and uses info rmation from initial, limited investigations to assess the relative threat that sites with actual or potential contaminant releases pose to human health or the environment. Currently, HRS scoring is based on an evaluation of the release of hazardous substances from sites via four pathways: surface water migration, ground water migration, air migration and soil exposure. The HRS identifies the relative risk among sites with the calculated score reflecting the probability that one site poses a greater threat
than another.

1. The ground water migration pathway evaluates the likelihood that hazardous substances will migrate to ground water and contaminate aquifers and drinking water wells that draw on those aquifers.

2. The surface water migration pathway evaluates the likelihood that hazardous substances can enter surface water and affect people or the environment. Threats to humans from this pathway include

12 EPA also considered the use of mitigation systems rather than source control at sites with SsI contamination. While mitigation systems can control human

exposur es, these systems have several limitations, including the need for multiple blowers at complex structures and the impact of t hese systems on climate control costs in large structures; the need for long

- term monitoring due to long time frames for migration and exposure; and the need to maintain the systems to address the impacts of contamination.

13 The full survey and results are available at http://www.itrcweb.org/vaporintrusionresources/ITRC_VI_Survey_8

- 17

- 05/ITRC_1_VI_Survey_Index

.

14 See, for example, OSWER Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air, Office of

Solid Waste and Emergency Response, U.S. Environmental Protection Agency, June 2015, and Final Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air, Department of Toxic Substances Control, California Environmental Protection Agency, October 20 11

.

### 4 

### drinking water, the human food chain (i.e., contaminants accumulate in the aquatic organis ms that humans in turn consume) and sensitive environments.

3. The air migration pathway evaluates the likelihood of release of hazardous substances into the atmosphere and the number of people and sensitive environments actually or potentially exposed to
ha zardous substances carried in the ambient air, including gases and particulates.

4. The soil exposure pathway evaluates the potential threats to humans and terrestrial environments posed by direct, physical contact with, and subsequent ingestion of, hazardous substances. This pathway includes threats to people living on property where hazardous substances are present in the surface/subsurface, including contaminated soils, and to people living nearby with access to the
contaminated area.

The HRS was last revi sed in 1990, but did not include an SsI component as the science was not sufficiently advanced to ensure the effectiveness of its use in a screening tool. The ground water and soil exposure pathways consider contaminated ground water and contaminated surfa ces (e.g., surface soils), respectively, but neither addresses vapor

- phase contaminants that can enter buildings and pose a threat to occupants. The air migration pathway considers the threat posed by contaminants released to ambient (atmospheric) air, but does not address indoor air, and has no subsurface component. The surface water pathway is not applicable to SsI contamination because contaminated surface water bodies are extremely unlikely to be a source of SsI contamination into occupied structures. T herefore, although the purpose of the HRS is to assess the relative degree of risk to human health and the environment posed by the release or potential release of contaminants, the HRS currently contains no mechanism for evaluating the threat to human hea lth posed by SsI contamination.

This proposed rule mandates only the addition to the HRS of the capability to rank sites with SsI threats . It does

not specifically mandate how

, to what sites

, and under what conditions the HRS will be applied. Moreover, site listings and accompanying potential response actions are not directly affected by this proposed rulemaking. The primary purpose of the NPL is to serve as an informational and management tool. The identification of a site for the NPL is intended to gui de EPA in determining which sites warrant further investigation to assess the nature and
extent of the human health and environmental risks associated with a site , and to determine what Federally

financed remedial action(s), if any, may be appropriate. The NPL also serves to notify the public of sites EPA believes warrant further investigation. Sites on the NPL are then further investigated to determine the nature and extent of the threat and whether cleanup of the site under EPA ’s Superfund Remedial progra m is warranted.

P lacing a site on the NPL does not specifically mandate any specific remedial or removal action. In some cases, further investigation may conclude that no remedial action is necessary

.

Scope of the Effects of the Proposed Rule

Contaminate d sites are evaluated through EPA’s Site Assessment program to determine their potential to be added to the NPL. The evaluation of sites involves a series of initial, limited site investigations and data collection
efforts related to site conditions. This process is implemented by the EPA regional site assessment programs. Investigations often include a Preliminary Assessment, Site Inspection (SI), and related investigations. The HRS evaluation uses the information obtained from these initial, limited inves tigations to rank sites according to the risk they may pose, relative to other sites, and determine if further investigation is warranted through the Remedial or Removal programs.

### 5 

### Each EPA region has a set budget for conducting site assessments. The sites in each EPA region of the country are reviewed to determine those that pose the highest risk and are prioritized accordingly. The addition of an SsI component to the HRS is not expected to result in additional site assessment funding to account for any inc rease in site assessment costs. Instead, the pipeline of sites will continue to be reviewed under the site assessment process. If it is found that SsI- contaminated sites potentially pose a greater risk than other sites, then these sites will be prioritized over other sites with contamination not resulting from SsI.

This proposed addition to the HRS will have the most significant impact on EPA’s Superfund cleanup program. The current HRS considers releases to the ground water, surface water and air, as well as direct exposure to contamination such as soil in identifying the sites that most warrant g further investigation . If promulgated, this proposed rule will not impact the way the current HRS addresses these releases. However, in the course of present
HRS assessments, sometimes subsurface intrusion issues are coincident with a ground water or soil contamination problem. The HRS presently does not consider the threat posed by sites with subsurface intrusion problems and direct human exposure, when ground wa ter is not being used as a drinking water source or surficial soils are not contaminated. If promulgated, this proposed rule will for the first time allow the EPA site assessment program to address sites with only subsurface intrusion issues which do not h ave any coincidental exposure from another pathway already evaluated by the HRS . Furthermore, proposal of this addition will not disrupt EPA’s listing of sites. However, it could lead to an increase in some site assessment activities and related costs.

Although this proposed addition will impact both resources and costs to federal cleanup programs

, EPA does not expect that this proposed change will result in additional site assessments being conducted per year or placement of more sites on the NPL per ye ar . Rather, given potentially limited budgets and the possibility of increased costs for an SsI site assessment, EPA may conduct fewer assessments per year. The pipeline of sites will be reviewed to identify those sites that pose the highest risk and prior itized accordingly. This is not a change to how EPA currently evaluates and prioritizes sites for the NPL; EPA will simply have an additional mechanism to address sites that pose the greatest risk. Because assessing the worst sites first is a priority, EPA will continue to identify the sites posing the highest risk or potential risk and develop a strategy to assess those sites in a timely manner, while balancing their other site assessment needs.

The proposed rule will also affect how EPA , federal agencies and its State Cooperative Agreement partners conduct site assessments and HRS scoring. The CERCLA site assessment program is operated strictly by the public sector using funds that are appropriated annually and reside in the Superfund Trust Fund. State and tribal partners may receive financial assistance from EPA to evaluate sites through a Cooperative Agreement. EPA and states or tribes collaborate closely throughout the Cooperative Agreement process, particularly when identifying
sites to be evaluated and establishing priorities for performing evaluations. As necessary, sites where subsurface intrusion threats exist may then be evaluated using the HRS and, if warranted, proposed for placement on the

NPL. The proposed rule does not impose any costs on outsi de parties or any private entity ; it does not require that EPA will necessarily undertake response actions, nor does it require any action by a private party or determine liability for site response costs. Costs are limited to screening relevant sites for SsI during site inspections and the resulting HRS evaluation and documentation record preparation. Costs that arise from site remedial responses are
the result of site

- specific decisions made post

- listing, not directly from the act of listing itself.

As d iscussed above, no other authority consistently and comprehensively addresses SsI contamination across all potential sites, particularly when SsI is the key exposure pathway. While most states have identified SsI sites as a high priority, not all states ha ve SsI programs, and states with programs var y in their authority, resources and
remediation criteria. A redirection of resources available to the states through Cooperative Agreement funding is expected to provide for greater national consistency in the identification and evaluation of SsI sites. Additionally,

### 6 

### EPA issued new vapor intrusion guidance in June 2015, OSWER Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air , which together with this proposed rule, EPA expects will provide a comprehensive framework to guide evaluation of SsI sites across the country.

Additional Impacts Associated with Future Regulatory Actions that are Enabled by th e Proposed
Rule

Scoring a site in the HRS imposes no costs on any private entity. Once EPA or a State conducts a site assessment
and determines that a site is NPL -caliber, additional regulatory actions must be taken before any costs or other impacts would occur. The information provided on SsI contamination through a revised HRS might be used in several ways. For example, a State may opt to address the SsI concern through state statutory and regulatory authorities; these subsequent site- specific state actio ns could potentially impose additional impacts on State taxpayers or on private entities that may be liable under state law. Placing a site on the NPL also impose s no impacts on any private entity, because placement on the NPL does not ascribe liability or in any way impose requirements on private parties. Later decisions that consider information collected under the proposed rule could separately have specific economic costs and benefits (e.g., remediation costs and reduced risk)

, but these impacts

are con tingent on separate actions. 15 

### The addition of SsI to the HRS is several regulatory steps removed from imposing any costs on private entities.

1.4. Alternative Regulatory Options

This analysis considers the economic impacts of three regulatory options that vary in how a site with a potential
SsI threat will be scored for the HRS:

• 

### O ption 1 – Score only populations and regularly occupied structures within a zone defined by exposures above background and resulting from subsurface intrusi on attributable to the site being evaluated . Under this option, scoring will include both actual contamination for sampled structures and inferred
contamination for regularly occupied structures within the Area of Observed Exposure (AO E ). The AOE is bounded by structures with documented contamination subsurface intrusion attributable to the site being evaluated

.

• 

### Option 2 (the preferred option) – Score only populations and regularly occupied structures within zones with actual exposure , as well as those above demonstrated subsurface contamination. Under this option, a site’s score will include actual contamination for sampled structures and inferred contamination both for regularly occupied structures in the AOE and for regularly occupied structures in the Area of Subsurface
Contamination ( ASC ). The ASC is defined as an area outside of the AOE by sampling locations with documented contamination significantly above background and the significant increase can be attributed at least in part to the site being evaluated (e.g., ground water and soil gas sampling points).

• 

### Option 3 – Score all populations in zones with actual or potential exposure. Under this option, in addition

to ac tual contamination for sampled structures and inferred contamination for regularly occupied

15 It is important to recognize that when a site is scored and determined to warrant further inves tigation , community members may experience short term indirect (contingent) social costs and benefits. For example, release of a site score may affect property values in surroundi ng areas either by signaling contamination or by signaling intent to remediat e known contamination. Similarly, the costs of remediating the site and the benefits of identifying and mitigating risk would be informed in part by the information provided under the proposed rule.

### 7 

### structures in the AOE and the ASC , a site’s score will include potential future contamination for regularly occupied structures in the Potential Ground Water Migrat ion Zone (PMZ). The PMZ is defined as an
area between the ASC and a target distance limit encompassing the potential area where the ground water or soil gas contamination plume may migrate in the future.

The three regulatory options are summarized and com pared in Exhibit 1 -1.

1.5. Scope of Analysis

Within the constraints of data availability, this analysis attempts to capture all quantifiable and qualitative impacts
of this proposed rule. Costs of implementing the proposed rule include the costs of investigating SsI contamination at sites with probable SsI threats and the additional administrative costs of conducting HRS evaluations for sites that score 28.50 or higher due in part to SsI con tamination. The analysis compare s the costs
of the three regulatory options presented in section 1.4 above. While the analysis portrays the various options as though they will result in additional expenditures for site assessments and HRS package preparati ons, in the context of a fixed site assessment budget, it is likely that the cost impacts of the proposed rule would manifest in a reduction in site assessment activity , and would result in no incremental costs at all.

The analysis qualitatively discuss es the potential benefits of adding an SsI component to the HRS. These potential benefits include, among others, improved quality of information about SsI threats; more effective prioritization of remedial efforts by the Superfund program through a more compr ehensive characterization of sites with SsI
threats ; and alerting the Superfund r emoval program to early risks which may be mitigated through taking an
immediate action.

Finally, this Regulatory I mpact A nalysis discusses the impact of this action within th e context of relevant executive orders and statutes. Because the costs of the proposed rule are expected to be small (i.e., below $ 3
million per year ), this document does not include a separate analysis of potential economic impacts (e.g., job impacts, imp acts on trade, impacts on productivity).

### 8 EXHIBIT 1 -1 . OPTIONS CONSIDERED FOR THE PROPOSED RUL E

OPTION FOR SCORING P OPULATIONS POTENTIAL

NUMBER OF

INTRUSION SITES

ASSESSED POTENTIAL

NUMBER OF NPL

CALIBER

INTRUSION SITES PROS/CONS CONSISTENCY WITH OTH ER HRS PATHWAYS

Option 1

– Consider Only Actual and Inferred Exposures

• Includes all actual and inferred

contamination for regularly occupied structures within the Area of Observed Exposure ( AO E)

• Does not include potential exposure for

regularly occupied structures outside the AO E Less Least Pro: Will have a high probability that identified releases pose a risk when scoring by zones of contamination

Con: Could fail to identify sites warranting further investigation because potential exposures will not be considered; does not consider future conditions/migration and may necessitate greater review of sites given a “no further action” designation Option is co nsistent with:

• The soil exposure pathway in that it

does not consider potential targets and infers Level II contamination

• All pathways in how Level I and II

targets are weighted

Option 2 (Preferred Option)
– Consider Actual , Inferred and Probable Exposure s

• Includes those regularly occupied

structures within the AO E and the Area of Subsurface Contamination ( AS C)

• Includes both actual contamination

intrusion and probable exposure to subsurface contamination for regularly occupied structures within the AO E and AS

C Less Middle Pro : Would ensure that most releases posing a significant risk are identified by relying upon lines of evidence

Con : Could lead to an underestimate of the number of releases because future migration of subsurface contamination is not accounted for and/or because lines of evidence gathered during the Site Assessment process may be incomplete ; does not consider future conditions/migration and may necessitate greater review of sites given a “no further action” designation Option is consis tent with:

• The soil exposure pathway in that there

is no inference of contamination for Level I targets

• The soil exposure, air and surface water

pathways in that there is inference of contamination for Level II targets

• The air pathway in that on

- source

tar gets are weighted (partially consistent – weighting values are different)

• All pathways in how Level I and II

targets are weighted

### 9 OPTION FOR SCORING P OPULATIONS POTENTIAL

NUMBER OF

INTRUSION SITES

ASSESSED POTENTIAL

NUMBER OF NPL

CALIBER

INTRUSION SITES PROS/CONS CONSISTENCY WITH OTH ER HRS PATHWAYS

Option 3

– Consider Actual , Inferred, Probable and Potential Exposures

• Includes regularly occupied structures

within the AO E , the ASC and the Potential Ground Water Migration Zone (PMZ)

• Includes actual contamination intrusion,

probable and potential exposure to subsurface contamination for regularly occupied structures within the AO E

, AS C and PMZ

• Includes unsampled structures, but are

considered to be potentially exposed More Most Pro: Would ensure that all releases posing a risk are identified

Con: Could result in identification of low risk releases because not all identified releases will result in future
exposure ; limited rationale for projecting extent of PMZ; not assuming migration in all directions (i.e., <360 degrees) could result in questioning the target delineation for ground water and air pathways Option is consistent with:

• The air pathway in that there 2

different weightings for potential targets

• The air pathway in that on

- source

targets are weighted (partially consistent – weighting values are different)

• The ground water pathway in that the

same weighting values are used

• All pathways in how Level I and II

targets a re weighted

### 10 

### 1.6. Organization of Document

The remainder of this document is organized as follows:

• Chapter 2: Sites Affected by the Proposed Rule

. This chapter describes how EPA identified and
characterized sites potentially affected by the proposed rule.

• Chapter 3: Impacts of the Proposed Rule

. This chapter presents quantitative estimates of the cost impacts of the proposed rule and includes a qualitative discussion of expected benefits of the rule.

• Chapter 4 : Other Statutory and Executive Order Analyses. This chapter summarizes analyses required by applicable statutes or executive orders, including impacts on low-income and minority populations; children’s health effects; federalism implications ; effects on tribal governments; and a demographic analysis to assess the potential for disproportionate effects on l ow-income and minority populations.

• Chapter 5 : Summary. This chapter compares the costs of the proposed rule across the three regulatory options and includes a discussion of the rationale for selection of the preferred option.

### 11 

### 2. Sites Affected by the Proposed Rule

At some sites with subsurface contamination (e. g., chemical spills, leaks from underground storage tanks), many hazardous substances, especially volatile organic compounds, have been shown to migrate into the indoor air

space s of overlying or nearby structures. The most common hazardous substances that have been shown to migrate into indoor air include mercury, tetrachloroethylene, trichloroethylene, vinyl chloride carbon tetrachloride and naphthalene.

To support the proposed rulemaking , the U.S. Environmental Protection Agency ( EPA ) conducted a screening

level assessment of sites with potential or identified subsurface intrusion ( SsI ) threats. As a first step in collecting the list of sites potentially affected by the propose d rule, EPA consulted with site assessment experts that work in Superfund and other federal programs, including Brownfields, Resource Conservation and Recovery Act and other Federal/state programs. These experts used their professional knowledge and famili arity with their programs’ historical data to identify potential site candidates. EPA also reached out to state counterparts, in particular state programs that were known to have taken a more thorough review of the SsI pathway at sites.
These efforts to id entify and classify sites that may pose a subsurface intrusion threat resulted in the identification of 1,073 sites that may or may not qualify for the National Priorities List ( NPL ) but are suspected of having vapor
intrusion issues. (See Appendix A of th e Technical Support Document for this proposed addition (Proposal TSD) for the inventory of vapor intrusion sites. ) Many of the sites in this inventory are currently listed in the EPA’s Superfund database 16



### . These sites are not currently on the NPL, and all have a potential or identified SsI threat. 17 

### Within the group of sites potentially affected by the proposed rule, EPA defined four categories or tiers of sites :

1. Tier 4: Sites i dentified as having a suspected subsurface intrusion threat based on EPA’s Superfund
database and Agency for Toxic Substances and Disease Registry (ATSDR) key word searches, as well as
EPA or state self -identification, but for which no sampling data were obtained;

2. Tier 3: Sites identified as having characteristics or evidence that SsI (e.g., volatile hazardous substance in ground water) may have occurred or will occur ;

3. Tier 2: Sites identified as having a n SsI threat documented by subslab, crawl space, or indoor air samples
but i nsufficient HRS -required evaluation factors to qualify for the NPL; and

4. Tier 1: Sites identified as having an SsI threat with documented actual exposure of a sufficient number of targets and sufficient other HRS

- required evaluation factors to suggest the s ite may qualify for the NPL.

These categories are summarized in Exhibit 2 -1.

16 The EPA Superfund program is in the final stages of rep lacing the Comprehensive Environmental Response Compensation and Liability Act Information System (CERCLIS) data management system for Superfund site information, with the Superfund Enterprise Management System (SEMS) ( referred interchangeably with

the ter m EPA’s Superfund database).

17 The list of potentially affected sites discussed in this RIA represents information compiled and evaluated to date as part of an ongoing data collection effort. The full inventory of sites affected by this rule continues to b e refined and updated. The sites identified as part of the site inventory are not currently on the NPL. The sites currently part of the inventory of sites are all in varying stages of site assessment and only once the rule addition is promulgated and furth er information gathered, will it be known if these sites will be NPL

- eligible.

### 12 EXHIBIT 2

- 1. CATEGORIES OF SIT ES POTENTIALLY AFFEC TED BY THE PROPOSED RULEMAKING

CATEGORY POTENTIAL IMPACT NUMBER OF SITES

IDENTIFIED 1 ,2

Tier 4: Sites with a suspected SsI threat Site assessments for SsI are possible. 328

Tier 3: Sites with a probable SsI threat Site assessments for SsI are probable. 532

Tier 2: Sites with an identified SsI threat Site assessments for SsI are probable. HRS evaluations are possible. 202

Tier 1: Sites that currently may not score abov e 28.50 without considering SsI in the HRS HRS evaluations are probable; contingent impacts are possible if separate regulatory action is taken

. 11

Source : Technical Support Document for U.S. EPA’s Proposed R ule for Addition of a Subsurface Intrusion Component to the Hazard Ranking System, Appendix A, Inventory of Subsurface Intrusion Sites (2015)

. Note : 1. Site numbers exclude current and former National Priorities List ( NPL ) sites and are based on a preliminary EPA Regional Office review of sites using readily available data; numbers are not representative of the total universe of possible SsI sites. NPL sites are excluded because they are not expected to be affected by the i mpacts of the proposed rule (i.e., SsI investigation in site assessments and HRS evaluations for sites with an SsI threat). The sites identified as part of the site inventory are not currently on the NPL and are all in varying stages of site assessment and only once the rule addition is promulgated and further information gathered, will it be known if these sites will be NPL

- eligible.
2. Sites classified as Tiers 2, 3, and 4 are not currently on the NPL, but based on available information were determined to have possible vapor intrusion threats. Insufficient information is available to evaluate their eligibility for the NPL.



### EPA is also considering sites with another form of subsurface intrusion, namely, intrusion of contaminated ground water into regularly occupied structures

— which is an emerging issue. For example, a site was discovered where shallow (surficial) ground water contaminated with chromium had intruded into residential basements and after the water receded, or evaporated, a precipitate of chromium remained as a residue. The presence of this residue posed a significant threat to public health; however, the site could not be evaluated under the current HRS due to the lack of a mechanism to evaluate human exposure resulting from intrusion of contaminated ground water (subsurface intrusion contamination). The only viable option to place the site on the NPL was to rely on ATSDR
to make a determination that the exposure at the site posed a significant threat to public health. The decision to include sites on the NPL based on a determination by the Agency for Toxic Substances and Disease Registry is made infrequently because the HRS is the primary mechanism for p lacing a site on the NPL.

EPA regional site assessment programs have identified 7 additional sites where intrusion of contaminated ground water is a potential issue and the related threat cannot be evaluated using the current HRS. Under the proposed SsI addition, ground water intrusion would be evaluated using current conditions, which may involve situations where metals have precipitated from water or where volatile substances have entered a structure via infiltrating ground water. As EPA further explores this emerging issue, the agency considers it likely that other ground water intrusion sites requiring evaluation will be identified.

This inventory of sites, identified by EPA, with a possible subsurface intrusion threat, is not representative of the

mag nitude of the potential scope of sites with subsurface intrusion contamination. EPA identified these sites based on currently available information to initially assess the subsurface intrusion problem. This list of sites illustrates that there currently ex ists at least 1,073 sites that have significant actual or potential human exposure

### 13 

### due to subsurface intrusion, but because of the shortcomings of the 1990 HRS cannot be evaluated to determine if they warrant addition to the NPL.

It is also important to e mphasize that the inventory of sites compiled (where subsurface intrusion has been identified as a possible issue) does not represent a list of sites that will be placed on the NPL. EPA recognizes that, in many instances, additional information is needed to verify the presence, and to determine the nature/extent, of a subsurface intrusion problem. As such, the inventory should not be considered as a list of NPL
candidate sites.

In Chapter 4, the analysis of possible indirect (contingent) demographic impact s uses data characterizing populations in the areas surrounding sites potentially affected by the proposed rulemaking to identify potential impacts to low-income and minority communities. Alt hough this component does not reflect a representative sample of the total universe of possible SsI sites, EPA determined the group of potentially affected sites to be sufficiently indicative of possible SsI sites for purposes of identifying potential environmental justice concerns.

### 14 

### 3. Impacts of the Proposed Rule

3.1. Introduction

This Regulatory Impact Analysis (RIA) uses available data from Information Collection Review (ICR) documents, the U.S. Environmental Protection Agency ( EPA ) Regional Offices and other sources to quantify the expected costs of the proposed rule. As described in Chapter 1, the proposed rule is a narrow technical
modification of the Hazard Ranking System ( HRS ). For the regulatory options examined in this analysi s, the primary impact of the proposed action would be that the Superfund program would routinely consider subsurface intrusion ( SsI ) threats in site assessments. In addition, EPA expects that a number of sites investigated for SsI will
achieve HRS scores o f 28.50 or higher, resulting in increased administrative effort to prepare and evaluate listing packages.

Executive Order 12866 requires that RIAs evaluate whether regulatory actions are “significant” rulemakings ; one determination of significance is whet her annual cost impacts exceed $100 million. To determine whether the

annual cost of the proposed rulemaking exceeds the $100 million threshold, this analysis considers the following costs that would result from the proposed amendment to the HRS:

• 

### Cost to conduct SsI investigation s , specifically site inspections (SIs) and expanded site inspections (ESIs) for sites with a probable SsI threat.

• 

### Cost to prepare HRS packages for sites that score 28.50 or higher based entirely or in part on
consideration of an Ss I threat

. To differentiate the incremental benefits and costs of the proposed rule from baseline benefits and costs of the Superfund program, the analysis compares regulatory scenarios —in which the HRS is modified to consider SsI threats according to the three regulatory options described in Chapter 1—to a baseline scenario, in which the HRS remains unchanged. Note that although the analysis portrays the various options as though they will result in additional expenditures for site assessments and HRS package preparations, in the context of a fixed site assessment budget, it is likely that the cost impacts of the proposed rule would manifest in a reduction in site assessment activity , and would have little or no incremental cost.

In this chapter, the RIA qu antitatively estimates the costs that will be a n impact of the proposed action, comparing
the costs across the three regulatory options. The chapter outlines the cost estimation methodology, including the key assumptions used to define the baseline and reg ulatory scenarios, and presents cost estimates for each option.

B enefits of the proposed rule are expected to be limited and are therefore discussed qualitatively at the end of this chapter.

3.2. Cost Estimation Methodology

Th is section presents the methodology used to estimate the two categories of cost impacts considered in the analysis. For the baseline scenario and for each regulatory option, the analysis first identifies values for the following variables:

1. Number of site assessments at SsI and non- SsI sit es.

2. Number of HRS packages prepared for SsI and non- SsI sites.

### 15 

### 3. Average cost per site assessment at SsI and non- SsI sites.

4. Average cost per HRS package prepared for SsI and non- SsI sites.

For each regulatory option, the analysis estimates the average cost per site assessment at SsI sites for both a highend regulatory scenario, using the upper range of the estimated costs of a site investigation for an SsI site, and a
best

- estimate regulatory scenario, using the median estimated costs of an SsI investigation

. The remainder of this section discusses how the analysis defines the baseline and regulatory scenarios and provides additional detail on how the analysis models the cost of site assessments at SsI and non- SsI sites.

3.2.1. 

### Characteristics of the Basel ine Scenario

The baseline scenario is defined as follows:

• 

### SsI is not currently considered during site assessments or in the HRS.

• 

### The Superfund program typically assesses approximately 2 00 sites per year.

• 

### The Superfund program typically prepares 20 HRS package s per year at a cost of $65,000 per package. 18



### The assumption of 2 00 sites assessed per year is consistent with the average number of sites assessed annually,
based on data from EPA’s Superfund database during the 5 year period between 2011 and 201 5. 19



### 3.2.2

. 

### Characteristics of the Regulatory Scenarios

The three regulatory options evaluated in this RIA are summarized in Exhibit 1-1 . To estimate the costs associated with each option, the analysis makes the following assumptions, common to all three options:

• 

### For assessments of sites with SsI threats, only the costs of SIs and ESIs will change because evaluation of
SsI threats occurs only during these investigations. Costs for other site assessment activities (i.e., preliminary assessments, integrated assessments and site reassessments) will be the same as for non

- SsI
sites.

• 

### All new SIs and ESIs for SsI will take place at sites that would not receive site assessments absent the regulation. This assumption is conservative because SsI threats will likely be investigated in conjunction with other pathways, such as ground water migration or soil exposure.

• 

### New site assessmen ts for SsI will replace lower -priority site assessments at non- SsI sites that are expected to take place in the baseline scenario.

• 

### New HRS packages for sites scoring 28.50 or higher will be prepared for site s that score solely based on
SsI or based on SsI combined with other factor/pathway scores.

18 The number and cost of HRS packages are based on data collected in support of Information Collection Request (ICR) 1488.08, provided by Randy Hippen,

EPA OSRTI, on June 7, 201 1.

19 SEMS Accomplishment Reports data provided by Randy Hippen, EPA Office of Superfund Remediation and Technology Innovation ( OSRTI ) , on October 30,

2015. The number of annual preliminary assessments conducted between FY 2011 and FY 2015 ranged from 171 to 242. For purposes of this analysis a baseline of 200 assessments was selected as it was consistent with previous program activity.

### 16 • 

### New HRS packages prepared for SsI sites will replace HRS packages for lower

- priority sites expected to be prepared in the baseline scenario.

• 

### The cost of preparing HRS packages for SsI sites will be the same as th e cost for non- SsI sites: $65,000 per site.

• 

### Because of the uncertainty involved in determining the costs of evaluating SsI threats as part of the site assessment process, the analysis will use a range of values to represent the costs of SIs and ESIs for Ss I. These values will be presented as h igh -end and best- estimate scenarios for each option.

• 

### The rule will not create any backlog effects (e.g., in which a larger number of sites are identified in initial years, then the number goes down over time).

In addi tion, to compare costs across the three regulatory options, the analysis makes the following option- specific assumptions:

• 

### For Option 1 , the analysis assumes that the Superfund program will conduct 20 site assessments for SsI and prepare one HRS package for SsI sites each year.

• 

### For Option 2 , the analysis assumes that the Superfund program will conduct 20 site assessments for SsI and prepare two HRS packages for SsI sites each year.

• 

### For Option 3 , the analysis assumes that the Superfund program will conduct 40 site assessments for SsI and prepare four HRS packages for SsI sites each year.

The assumption that the Superfund Office will assess 20 SsI sites in place of non- SsI sites under Options 1 and 2 is based on a survey EPA conducted of EPA Regional Superfund Offices indicating that approximately 10 percent
of sites assessed will likely have SsI threats

. 20 

### EPA considered the different thresholds and methods that would be used for each of the regulatory options to investigate SsI threats and determined that th e modeling approach used in Option 3 would bring a larger number of sites into the scope of analysis for SsI threats. Accordingly, the analysis assumes that under this option, EPA would conduct 40 site assessments at SsI sites each year.

The aforementioned survey of EPA Regional Offices also estimates that approximately one percent of site assessments are expected to result in HRS scores of 28.50 or higher , based in part or entirely on SsI threats. This percentage is based on the number of Tie r 1 sites identified as having an SsI threat with documented actual exposure of a sufficient number of targets and other HRS- required evaluation factors to suggest the site may qualify for the National Priorities List (NPL). (Please see section 2 of this d ocument for additional information on the inventory of sites identified with possible vapor intrusion threats.) These sites would be new sites that may not have previously qualified for placement on the NPL . However, given limited budgets, the addition of SsI to the HRS will not result in more sites listed per year. Rather, the pipeline of sites will be reviewed and if the SsI

contaminated sites identified potentially pose a greater risk than other sites, they will be more highly prioritized. This is not a change to how EPA currently lists sites on the NPL; EPA simply would have an additional mechanism to address sites that pose the greatest risk.

For Option 2 , the analysis therefore assumes that the Superfund program will prepare two HRS packages per year
due to SsI assessment activities under the proposed rule. Because Option 1 is less likely to identify risks that exceed an HRS score of 28.50 (see Exhibit 1-1) , the analysis assumes that this option would involve preparation

20 EPA conducted a survey of EPA Regional Superfund Offices in 2011 to support the development of the database of sites with an SsI threat. The survey asked

EPA Regional Managers to submit information about Draft Vapor Intrusion Site Information Collection Matrix, Jennifer Wendel, National Priorities List Coordinator, EPA Region 4.

### 17 

### of only one HRS package per year for an SsI site. Similarly, because Option 3 allows consideration of broader populations and areas, the analysis assumes that the Superfund program would prepare four HRS packages per

year for SsI sites under t his option . Exhibit 3- 1 summarizes the key characteristics of the baseline scenario and
three regulatory options that affect the cost analysis

.

EXHIBIT 3

- 1. CHARACTERISTICS O F THE BASELINE SCENA RIO AND THREE REGULATORY OPTIONS

CONSIDERED IN THE CO ST ANALY SIS

BASELINE OPTIONS 1 OPTION 2 OPTION 3

Non

- SsI Sites Assessed per Year 200 180 180 160

SsI Sites Assessed per Year 0 20 20 40
HRS packages prepared at non

- SsI sites per year 20 19 18 16

HRS package s prepared at SsI sites
per year 21 0 1 2 4

Cost per HRS package $65,000



### As discussed earlier in this section, for purposes of this analysis, it is assumed that new site assessments of sites
with SsI threats will replace site assessments at non

- SsI sites; therefore, the total number of sites assessed annually will remain the same for the baseline scenario and the three regulatory options being considered . The
number of SsI sites evaluated and the number of HRS packages prepared for SsI threats in each of the three regulatory options reflects the methodology considered for evaluating the SsI threat. For example, Option 1
consider ed only regularly occupied structures and populations within an area (i.e., area of observed exposure ( AOE )) delineated by regularly occupied structures with documented contamination resulting from subsurface intrusion attributable to the site being evaluated. Option 2 consider ed regularly occupied structures and populations within an AOE and areas outside that of an AOE (i.e., areas of subsurface contamination ( ASC )) , for which subsurface intrusion has been documented at levels significantly above background and the significant
increase can be attributed

, at least in part

, to the site being evaluated. Option 3 considered the aforementioned AOEs and ASCs, as well as a potential ground water migration zone, which represented an area where ground water or soil gas contamination may migrate in the future. The analysis also assumes that the cost of SIs and ESIs

at SsI sites will be different for each option. These differences are discussed in detail in the following section.

3.2.3. 

### Methodology for Estimating the Cost of Site Assessments at SsI and non

- SsI Sites

T he analysis assum es that the proposed rule will result both in additional assessments at sites with potential SsI threats and in additional costs to incorporate SsI investigation in SIs and ESIs. Because not every assessment at a site with a potential SsI threat will necessarily involve an SI or an ESI for SsI (i.e., some sites will not proceed beyond a preliminary site assessment), the analysis develops a weighted

- average cost per site assessed for each regulatory option that accounts for different SI cos ts. The weighted

- average cost per site assessed accounts for the
costs of the five key activities that can take place during a typical site assessment:

21 The number of HRS packages prepared per yea r at SsI sites equals the number of SsI sites that are estimated to be added to the National Priorities List under

each regulatory option considered.

### 18 

### 1. Preliminary Assessment

2. Site Inspection

3. Integrated Assessment

4. Site Reassessment

5. Expanded Site Inspection

EPA looked at ICR data and SEMS Accomplishment Reports data to determine the frequencies of site assessment activities and average costs per activity. 22 

### The analysis then weighted the cost of each activity by its frequency to
calculate a weighted

- average co st per site assess ed . Exhibit 3-2 shows the derivation of the weighted- average cost per assessment at a non

- SsI site (i.e., the cost of a site assessment in the baseline scenario)

.

EXHIBIT 3

- 2. WEIGHTED AVERAGE COST PER ASSESSMENT AT A NON

- SSI SITE

SITE ASSESSMENT ACTIVITY COST PER

ACTIVITY 1 PERCENT OF SITE S

ASSESS ED WITH

EACH ACTIVITY 2 WEIGHTED

COST 3

Preliminary Assessment $14, 300 100% $14,300 Site Inspection $45,0 00 4 4

% $ 19,700 Integrated Assessment $38,800 4 % $ 1,4 00

Site Reassessment $20,3 00 66 % $ 13, 4 00 Expanded Site Inspection $92,3 00 10% $ 9, 700 Total Weighted Average Site Assessment Cost $ 58, 4 00

1. Costs per activity are based on data collected in support of ICR 1488.08, provided by Randy Hippen , EPA Office of Superfund Remediation and Technology Innovation (OSRTI)

, on June 7, 2011.
2. Percent of sites assessed with each activity are based on national SEMS Accomplishment Reports data provided by Randy Hippen

, EPA OSRTI , on October 30

, 201 5.
3. Individual cost values were calculated using original unrounded input values ; each final value presented in this exhibit was rounded to three significant digits.



### To determine how investigating a potential SsI threat would affect the cost of site assessments, EPA developed a

concep tual site model (CSM) to estimate costs of a site inspection at a typical SsI site. 23 

### For this model, EPA defined a typical site with an SsI threat. As noted previously, this analysis assumes that investigations for SsI
occur at sites where SsI is the only threat examined. The CSM specifies the following key variables related to SI

cost:

22 Costs per activity are based on data collected in support of ICR 1488.08, provided by Randy Hippen, EPA OSRTI, on June 7, 2011. The percent of sites

assessed with each activity are based on SEMS Accomplishment Reports data provided by Randy Hippen, EPA OSRTI, on October 30, 2015. The EPA Superfund program is in the final stages of replacing the Comprehensiv e Environmental Response Compensation and Liability Act Information System data management system for Superfund site information, with SEMS.

23 For purposes this model, EPA defined a site inspection to encompass both SIs and ESIs.

### 19 

### 1. Duration of the SI (4 days),

2. Number of new ground water monitoring wells installed and the number of ground water samples collected from new and existing wells (6 wells ins talled, 10 ground water samples collected);

3. Number of soil gas samples taken ( 12 samples) ;

4. Number of sub- slab vapor samples taken (32 samples);

5. Number of indoor air samples taken (32 samples); and

6. Laboratory methods used to analyze and validate ground water and vapor samples (10 ground water samples and 76 vapor samples analyzed and validated).

EPA collected unit costs from EPA Regional Offices, the Army Corps of Engineers and an EPA contractor, Tetra
Tech EM, Inc. to populate the model, using the media n cost from the different sources as a best

- estimate value and the maximum cost as the high -end value. 24 

### For the base case CSM, the value used for the best

- estimate scenario is $95,700 and the value used for the high-end scenario is $145,000. In addition, t he analysis makes the following modifications to the CSM to model differences in SI costs for the three regulatory options:

• Option 1 : Option 1 uses the values from the base case CSM.

• Option 2 : Option 2 modifies the CSM to include 12 additional ground water and 12 additional soil gas samples to characterize the extent of the ASC.

• Option 3 : Option 3 modifies the CSM to include 12 additional ground water and 12 additional soil gas samples, as in Option 2 , as well as additional analysis and reporting effort to identify the target population
in the Potential Groundwater Migration Zone ( PMZ ).

The variations on the CSM used to model costs for each of the regulatory options are summarized in Exhibit 3-4. The full methodology used to develop the conceptual site model is discussed in Appendix B.

The analysis estimates the weighted

- average cost of a site assessment at an SsI site by substituting the SI costs developed for the conceptual site model for both the cost of an SI and the cost of an ESI. 25 

### Exhibit 3 -3 shows the derivation of the weighted

- average cost per assessment at an SsI site, using the high-end scenario costs for Option 1 as an example. Exhibit 3

- 4 summarizes how the analysis estimates the cost of site assessments at SsI sites for
each of the regulatory options.

24 When estimating median and maximum cost values, the analysis first excludes unit costs considered to be outliers from certain SI tasks, particularly

planning, staging, oversight and reporting tasks. A complete discussion of the analysis’ treatment of outliers is presented i n Appe ndix B. Refer to Appendix D for costs associated with vapor intrusion site inspection tasks.

25 The site investigation activities specified in the CSM correspond most closely to an expanded site inspection (ESI). The RIA conservatively substitutes

conceptua l site model costs for both SI and ESI activities at SsI sites.

### 20 EXHIBIT 3

- 3. WEIGHTED AVERAGE COST PER ASSESSMENT AT AN SSI SITE, HIGH

- END SCENARIO COSTS

FOR OPTION 1

SITE ASSESSMENT ACTIVITY COST PER

ACTIVITY 1 PERCENT OF SITE S

ASSESS ED WITH

EACH ACTIVITY 3 WEIGHTED

COST 4

Preliminary Assessment $14, 300 100% $14,300 Site Inspection $ 145 ,0 00

2 44 % $ 63, 1 00 Integrated Assessment $38,800 4 % $ 1,4 0

0

Site Reassessment $20,3 00 66 % $ 13, 4 00 Expanded Site Inspection $ 145

, 000 2 10% $ 15, 3 00 Total Weighted Average Site Assessment Cost $ 10 7

, 00 0

1. Costs per activity are based on data collected in support of ICR 1488.08, provided by Randy Hippen , EPA OSRTI, on June 7, 2011.
2. See Exhibit D

- 1 for costs associated with an SI/ESI.
3. Percent of sites assessed with each activity are based on SEMS Accomplishme nt Reports data provided by Randy Hippen

, EPA OSRTI , on October 30 , 201 5.
4. Individual cost values were calculated using original unrounded input values ; each final value presented in this exhibit was rounded to three significant digits.

EXHIBIT 3

- 4. SUMMA RY OF SITE ASSESSMEN T COSTS AT SSI SITES 26

OPTION 1 OPTION 2 OPTION 3

Conceptual Site Model Characteristics

Dwellings sampled for sub

- slab and indoor air quality 32 32 32

Soil gas samples taken 12 24 24

Ground w ater samples taken 10 22 22

Effort to identify the Potential Ground Water Migration Zone Not included Not included Included

Cost per SI/ESI

High

- End Scenario $145,000 $182,000 $189,000

Best

- Estimate Scenario $95,700 $120,000 $127,000

Weighted Average Cost per Site Assessed

High

- End Scenario $ 10 7 ,000 $ 12 8 ,000 $ 13 2 ,000

Best

- Estimate Scenario $ 80,900 $ 94,000 $ 97,800

Note : Option 2 and 3 costs include analysis and validation costs for the additional 12 soil gas and 12 ground water samples.

26 Refer to Appendix D for costs with vapor intrusion site inspections.

### 21 

### 3.3. Cost Estimates

Exhibit 3

- 5 presents the key unit values used by the analysis to estimate the total costs of the proposed rule under
the three regulatory options considered in this RIA.

EXHIBIT 3

- 5. UNIT VALUES USED TO ESTIMATE COST IMP ACTS OF THE PROPOSED RULE 27

BASELINE OPTION 1 OPTION 2 OPTION 3

Sites Assessed per Year

N on

- SsI Sites 2 00 180 180 160

SsI Sites 0 20 20 40

Total Sites 2 00 2 00 2 00 2 00

HRS Package s per Year

N on

- SsI Sites 20 19 18 16

SsI Sites 0 1 2 4

Total Package s 20 20 20 20

Average Cost per Non

- SsI Site Assessed $ 58, 4 00 $ 58, 4 00 $ 58, 4 00 $ 58, 4 00

Average Cost per SsI Site Assessed

High End n/a $ 107,000 $ 128,000 $ 132,000

Best Estimate n/a $ 80,900 $ 94,000 $ 97,800

Average Cost per HRS Package $65,000 $65,000 $65,000 $65,000



### Using the unit values presented in Exhibit 3- 5, the analysis estimates high -end and best- estimate cost impacts for each regulatory option. These cost estimates are presented in Exhibits 3 -6 and 3- 7, respectively. Because all costs estimated in this chapter are annual ly occurring costs, no discount rates are used to estimate the present value of costs. Annual costs are constant regardless of the discount rates assumed.

27 Ibid

.

### 22 EXHIBIT 3 -6 . ESTIMATED ANNUAL COST IMPACTS OF THE PROPOSED RULE (HIGH

- END SCENARIO

, 2011$ )*

BASELINE

SCENARIO OPTION 1 OPTION 2 (PREFERRED OPTION) OPTION 3

NON -S S I

SITES NON -S S I

SITES SSI SITES TOTAL NON -S S I

SITES SSI SITES TOTAL NON -S S I

SITES SSI SITES TOTAL

Total Sites Assessed 200 180 20 200 180 20 200 160 40 200

Average Cost per Assessment $ 58,400 $ 58,400 $ 107,000 n/a $ 58,400 $ 128,000 n/a $ 58,400 $ 132,000 n/a

Total Assessment Costs $ 11, 7 00,000 $ 10,500,000 $ 2,150,000 $ 12,700,000 $ 10,500,000 $ 2,550,000 $ 13,100,000 $ 9,350,000 $ 5,270,000 $ 14,600,000

Total HRS Packages 20 19 1 20 18 2 20 16 4 20

Average Cost per HRS Package $65,000 $65,000 $65,000 $65,000 $65,000 $65,000 $65,000 $65,000 $65,000 $65,000

Total HRS Package Costs $1,300,000 $1,230,000 $65,000 $ 1,300,000 $1,170,000 $ 130,000 $ 1,300,000 $ 1,040,000 $ 260,000 $1,300,000

Total Costs $ 13,000,000 $ 11,800,000 $ 2,210,000 $ 14,000,000 $ 11,700,000 $ 2,680,000 $ 14,400,000 $ 10,400,000 $ 5,530,000 $ 15,900,000

Total Costs Attributed to Proposed Rule $ 979,000 $ 1,380,000 $ 2,930,000

* Individual cost values were calculated using original unrounded input values; each final value presented in this exhibit was rounded to
three significant digits.

### 23 EXHIBIT 3

- 7. ESTIMATED ANNUAL COST IMPACTS OF THE PROPOSED RULE (BEST

- ESTIMATE SCENARIO , 2011$ )*

BASELINE

SCENARIO OPTION 1 OPTION 2 (PREFERRED OPTION) OPTION 3

NON -S S I

SITES NON -S S I

SITES SSI SITES TOTAL NON -S S I

SITES SSI SITES TOTAL NON -S S I

SITES SSI SITES TOTAL

Total Sites Assessed 200 180 20 200 180 20 200 160 40 200

Average Cost per Assessment $ 58,400 $ 58,400 $ 80,900 n/a $ 58,400 $ 94,000 n/a $ 58,400 $ 97,800 n/a

Total Assessment Costs $ 11,700,000 $ 10,500,000 $ 1,620,000 $ 12,100,000 $ 10,500,000 $ 1,880,000 $ 12,400,000 $ 9,350,000 $ 3,910,000 $ 13,300,000

Total HRS Packages 20 19 1 20 18 2 20 16 4 20

Average Cost per HRS Package $65,000 $65,000 $65,000 $65,000 $65,000 $65,000 $65,000 $65,000 $65,000 $65,000

Total HRS Package Costs $1,300,000 $1,230,000 $65,000 $ 1,300,000 $ 1,170,000 $ 130,000 $ 1,300,000 $ 1,040,000 $ 260,000 $1,300,000

Total Costs $ 13,000,000 $ 11,800,000 $ 1,680,000 $1 3 ,400,000 $1 1,7 00,000 $ 2,01 0 ,000 $13,7 00 ,000 $1 0,4 00,000 $4,170,000 $14,6 00,000

Total Costs Attributed to Proposed Rule $ 450,000 $ 712,000 $ 1, 5 80,000

* Individual cost values were calculated using original unrounded input values; each final value presented in this exhibit was rounded to
three significant digits.

### 24 

### 3.4. Summary of Costs

Employing several conservative assumptions about the number of site assessments conducted and HRS packages prepared at SsI sites, as well as the high end of the range of estimated costs of an SsI investigation, the RIA
estimates that the cost impact of the proposed rule will be approximately $1.0 million for Option 1 , $ 1.4 million for Option 2 and $ 2.9 million for Option 3. Using the median costs of an SsI investigation from the CSM, the RIA estimates that the costs of the proposed action will be app roximately $ 0.5 million for Option 1, $ 0.7 million for Option 2 and $ 1.6 million for Option 3 . These costs are summarized in Exhibit 3 -8.

EXHIBIT 3

- 8. SUMMARY OF ANNUAL COST ESTIMATES FOR T HE PROPOSED RULE (2011$)

REGULATORY OPTION HIGH

- END COSTS
(MILLIONS) BEST

- ESTIMATE COSTS
(MILLIONS)

Option 1 $ 1.0 $ 0. 5

Option 2 (Preferred Option) $ 1.4 $ 0.7

Option 3 $ 2.9 $ 1. 6



### 3.5. Benefits

As noted in the introduction to this chapter, the RIA does not provide a quantitative estimate of benefits. B enefits of the rule are expected to be minimal, because the rule will not directly require actions that reduce risks. Any risk reduction that may result from the proposed action would come from future site- specific regulatory actions.

As stated in Chapter 1, the proposed action only affects EPA ’s ability to evaluate sites with actual or potential SsI threats for placement on the NPL if warranted; NPL listing informs the public that the site warrants further investigation and possibly response actions contingent on the results of future investigation. B enefits of the proposed action include improved quality of information and more effective prioritization of remedial efforts by the Superfund program through a more comprehensive characterization of sites with SsI thr eats.

Specifically, the proposed rule could improve the decision

- making of the Superfund program in three distinct

ways:

1. For s ites not yet on the NPL (but where SsI

- related contamination may be a concern) , the proposed rule would facilitate a more proactive and consistent SsI evaluation as part of the site assessment process, including application of the HRS, where necessary, to identify and prioritize sites posing the most immediate and serious potential threats to human health and the environment.

2. For s ites already placed on the NPL (scored by another pathway) , an early evaluation of potential SsI threats, including collection of SsI- related data, during the site assessment process would allow for a more

c areful consideration of such threats as part of the remedial investigation. As a result, these threats could be more quickly and comprehensively addressed (i.e., through source/soil control, ground water cleanup and/or SsI mitigation) than is currently the case.

3. For all sites with potential SsI contamination, the development of site information about SsI could
facilitate coordination between EPA and state and Federal agencies with authority related to site remediation, leading to more effective and integrat ed cleanup approaches.

### 25 

### In addition, it is possible— in situations where early SsI investigation uncovers a significant threat

— that the proposed rule could facilitate immediate r emoval actions. The RIA does not attempt to estimate the likelihood of such impa cts, however. Generally, the proposed action will not directly impact response actions that may occur at sites identified to pose a threat due to SsI . Accordingly, the proposed action is not expected to affect risk and will therefore not yield direct benef its to human health. Additionally, Option 2 has been selected as the preferred option as it is consistent with the 1990 HRS, serves as an effective screening tool that would both minimize unnecessary resource expenditures and the erroneous inclusion or exc lusion of sites from possible placement on the NPL, and is based on proven science.

3.6. Caveats and Limitations

Due to limitations in data availability and the uncertainties inherent in trying to predict future site assessment activities, the analysis makes several simplifying assumptions in order to develop a reasonable estimate of the impacts of the proposed rulemaking. Where possible, the analysis has chosen conservative assumptions in order to avoid underestimating costs. Examples of such assumptions include:

• 

### The analysis assumes that site assessments for SsI contamination would replace baseline activities that currently take place. The analysis does not consider the likelihood that some SsI site investigations might take place in conjunction with investigation of other pathways, and would therefore likely have lower unit

costs.

• 

### The analysis does not consider the possibility that site assessments for SsI threats could reduce costs by eliminating the need to investigat e one or more other pathways, such as ground water migration or soil

exposure.

• 

### To account for the range of cost estimates provided by EPA Regional Offices , the Army Corp s of Engineers and contractors for the costs of investigating SsI threats, the analysis estimates cost impacts using both the median CSM costs (in the best

- estimate scenario) and the maximum CSM costs, excluding outliers (in the high

- end scenario). The analysis therefore does not consider the possibility that future costs to investigate SsI threats could be less than the median CSM costs, particularly if investigation methods improve or greater economies of scale are realized when investigating a larger number of SsI
sites.

The use of such conservative assumptions in the analysis makes it possible that the analysis overestimates likely cost impacts of the proposed rule.

### 26 

### 4. Distributional Impacts and Considerations

As required by applicable statutes and executive orders, this chapter summarizes the U.S. Environmental Protection Agency’s ( EPA ) analysis of equity considerations and other regulatory concerns associated with the proposed rule. Regarding distributive impacts, transfer payments do not apply to this proposed addition , as the costs related to implementation of this proposed addition are already considered in the cost evaluation (see sections 3.2 through 3.5 of this document). This chapter assesses potential impacts with respect to the following
issues:

• Executive Order 12866 – Regulatory Planning and Review , and Executive Order 13563
– Im proving Regulation and Regulatory Review ;

• Executive Order 12580 – Superfund Implementation;

• Executive Order 12898 – Environmental Justice;

• Executive Order 13045 – Protection of Children from Environmental Health Risks and Safety Ris ks;

• Executive Order 13132 – Federalism ;

• Executive Order 13175 – Consultation and Coordination With Indian Tribal Governments;

• Executive Order 13211 – Actions that Significantly Affect Energy Supply, Distribution, or Usage;

• Paperwork Reduction Act;

• Regulatory Flexibility Act ;

• Unfunded Mandates Reform Act; and

• National Technology Transfer and Advancement Act.

4.1. Executive Order 12866
– Regulatory Planning and Review , and Executive Order 13563 – Improving Regulation and Regulatory Review

Under Executive Order (EO) 12866 the a gency must determine whether a regulatory action is “ significant ” and therefore subject to Office of Management and Budget (OMB) review and the requirements of the Executive
Order. The Order defines “ significant regulatory action ” as one that is likely to result in a rule that may: (1) Have an annual effect on the economy of $100 million or more or adversely affect in a material way the economy, a sector of the economy, productivity, competition, jobs, the environment, public health or safety, or State, local, o r tribal governments or communities; (2) create a serious inconsistency or otherwise interfere with an action taken or planned by another agency; (3) materially alter the budgetary impact of entitlements, grants, user fees, or loan programs or the rights a nd obligations of recipients thereof; or (4) raise novel legal or policy issues arising out of legal mandates, the President’s priorities, or the principles set forth in the Executive Order.

This Regulatory Impact Analysis ( RIA ) is designed to meet the re quirements under Executive Order 12866. The cost analysis (Chapter 3) concludes the following:

1. T he total annual costs of the proposed rulemaking are under $3 million in all regulatory scenarios, and will not have an annual effect on the economy of $100 million or more. In addition, because the proposed rule represents only a revision to EPA ’s current site assessment activities and does affect any specific sector of the economy, it will not have a significant impact on productivity, competition, jobs, or State,

### 27 

### local, or tribal governments or communities. As identified in Chapter 3, the proposed rule does not have any significant impacts on human health risk, the environment, or public h ealth or safety.

2. The proposed rule is consistent with EPA ’s current authority under section 105 of the Comprehensive Environmental Response, Compensation, and Liability Act ( CERCLA ), and does not alter the authority or affect actions taken or planned by an other agency. No o ther regulatory programs comprehensively or consistently address remediation of the source of the threat posed by SsI contamination when it is the key
exposure route.

3. The proposed rule affects only EPA ’s site assessment actions, and will not have a material impact on any entitlements, grants, user fees, or loan programs or the rights and obligations of recipients thereof; and

4. The proposed rule represents a revision to one existing pathway in the existing Hazard Ranking System ( HRS ) , and is consistent with EPA ’s current authority under section 105 of CERCLA. EPA has determined that this proposed rulemaking is a "significant regulatory action.” This proposed rule may raise novel legal or policy issues arising out of legal mandates, the Presi dent’s priorities, or the p rinciples
set forth in the EO. Accordingly, EPA submitted this action to the OMB for review under Executive
Order 12866.

Executive Order 13563 is supplemental to Executive Order 12866, and it reaffirms the principles of that order and requirements that agencies conduct a careful assessment of regulatory costs, benefits and other impacts. Executive Order 13563 also requires that EPA : 1) develop a regulatory adoption process that encourages publi c participation; 2) ensure that regulatory requirements do not place an inconsistent or overlapping burden on specific industries or sectors; 3) where feasible, consistent with regulatory objectives, and to the extent permitted by law, consider regulatory approaches that reduce burdens and maintain flexibility ; and 4) ensure the objectivity of any scientific and technological information and processes used to support the agency's regulatory action.

This rulemaking incorporates public comment procedures consistent with existing federal requirements, and does not represent an overlapping or inconsistent regulatory burden for any sector. The proposed rule is flexible in its application in that EPA has flexibility in developing effective approaches to site assessments at sites with potential SsI contamination. Finally, EPA has used objective and updated scientific and technological information in the development of this rulemaking. 28



### 4.2. Executive Order 12580
– Superfund Implementation

Executive Order 12580, Section 1(d), states, “ Revisions to the National Contingency Plan ( NCP ) shall be made in consultation with members of the National Response Team (NRT) prior to publication for notice and comment. Revisions shall also be made in consultation with the Director of the Federal Emergency Management Agency and the Nuclear Regulatory Commission in order to avoid inconsistent or duplicative requirements in the emergency planning responsibilities of those agencies. ” Executive Order 12580 delegates responsibility for
revisio n of the NCP to EPA

. The agency has complied with Executive Order 12580 by consulting with the NRT concerning the proposed addition of a new component to the HRS.

28 U.S. Environmental Protection Agency. Detailed Analytic Blueprint for HRS Addition of Vapor Intrusion: Tier 2 A ction . July 21, 2011.

### 28 

### 4.3. Executive Order 12898 – Environmental Justice

Under Executive Order 12898, as well as through EPA 's April 1995 Environmental Justice Strategy, the Office of Solid Waste and Emergency Response ( OSWER ) Environmental Justice Task Force Action Agency Report and National Environmental Justice Advisory Coun cil, EPA has undertaken to incorporate environmental justice into its policies and programs. 29 

### EPA is committed to addressing environmental justice concerns, and is assuming a leadership role in environmental justice initiatives to enhance environmental quality for all residents of the U.S.
The a gency's goals are to ensure that no segment of the population, regardless of race, color, national origin, or income, bears disproportionately high and adverse human health and environmental effects as a res ult of EP A 's policies, programs and activities.

As discussed in Chapter 3, the proposed rulemaking is expected to have only moderate costs and no impact on human health risk. Therefore, the rule has no impacts on communities considered under Executive Order 12898. Accordingly, EPA did not conduct a complete environmental justice analysis.

EPA did consider whether the proposed action might have contingent impacts on minority or low -income populations located near potential subsurface intrusion ( SsI ) sites if future actions affect remediation of these sites. The contingent demographic analysis summarized below concludes that potentially affected sites are located
in areas that have slightly higher concentrations of minority populations and populations below the povert y line than surrounding areas. Therefore, any future actions addressing risks in these communities would not contribute to disproportionate adverse impacts on human health. However, because SsI sites have the potential to pose a high
level of risk to resid ents and occupants of other buildings in their vicinity, EPA expects that there will be a realignment and reprioritization of its internal resources to address SsI sites. EPA is not able to predict the location of the sites without SsI contamination or demographic characteristics of populations living nearby.

This demographic analysis is summarized below and presented in Appendix C.

4. 3 .1. 

### Examination of Potential Contingent Demographic Impacts

Under Executive Order 12898, as well as through EPA ’ s Apri l 1995 Environmental Justice Strategy, OSWER Environmental Justice Task Force Action Agency Report and National Environmental Justice Advisory Council,

EPA has undertaken to incorporate environmental justice into its policies and programs. Specifically, Executive Order 12898 requires that EPA determine whether an action would have a disproportionate impact on low-income or minority populations. 30



### The proposed rulemaking does not have a specific impact on site remediation, and therefore has no impacts on
risk that would be relevant under Executive Order 12898. Any potential changes to human health risk resulting from the proposed action will be contingent on additional site- specific rulemakings. To ensure comprehensive consideration of the possibility of impac ts related to environmental justice, EPA considered the possibility that sites that are identified as having SsI contamination under the rule could potentially be located in areas

29 See U.S. Environmental Protection Agency, Draft Technical Guidance for Assessing Environmental Justice in Regulatory Analysis (2013)

.

30 Executive Order 12898, “Federal Actions to Address Environmental Justice in Minority Populations and Low

- Income Populations”, February 11, 1994. In
addition, EPA is currently developing technical guidance to support this executive order, to provide detail ed information on incorporating environmental justice into risk assessments, economic analyses and other scientific input and analytical documents as part of the agency’s rulemaking process. EPA is

committed to addre ssi ng environmental justice concerns, an d is assuming a leadership role in environmental justice initiatives to enhance environmental quality for all residents of the U.S. The a gency's goals are to ensure that no segment of the population, regardless of race, color, national origin, or income,

b ears disproportionately high and adverse human health and environmental effects as a result of EPA 's policies, programs and activities

.

### 29 

### characterized by populations with high concentrations of low-income or minor ity residents. T his analysis
examines demographic characteristics of populations living within 1 and 3 miles of sites identified in EPA ’s list of potentially affected non

- National Priorit ies List ( NPL ) sites (discussed in Chapter 2)

. 31 

### The demographic analysis indicates that areas around potentially affected sites have statistically higher concentrations of minority populations and populations below the poverty line than surrounding areas.

4. 3 .2. 

### Methodology

The analysis relies on U. S. 2000 Census data for census block groups and counties, and on site location data available in CERCLIS (EPA’s Comprehensive Environmental Response, Compensation, and Liability Information System), to identify the percent of the population near each site defined as minority and the percent of the population below the poverty line. 32 

### The analysis first calculates the proportion of the populations near each site that are minority or low -income, and then compares those populations with the population of the su rrounding
county for each site

. Rather than comparing demographic characteristics of the areas surrounding each site to national averages, EPA determined that c ounty- level statistics provide an appropriate scale for comparison to oneand three -mile buffer s. 33



### The demographic analysis examines populations within one and three miles of 240 of the approximately 1,073

s ites potentially affected by the proposed rule. 34 

### While this group of sites does not represent a representative sample of all sites, the analysis includes 240 sites distributed geographically across all EPA Region s. All sites are equally weighted.

For the areas within one- and three- mile radii of the selected sites, the analysis calculates the mean and median values for the minority share of the population and percent of the population below the poverty line. The analysis then applies a student’s paired, two- tailed t

- test to determine whether these values are statistically different from the demographic characteristics of the counties su rrounding the selected sites. A statistically significant positive
difference indicates that a greater percentage of the target demographic (i.e., minorities or people living below the poverty line) exists in the affected population than in the larger refe rence population. A statistically significant negative difference indicates a smaller percentage of the target demographic in the affected population.

4.3.3

. 

### Results

Exhibit 4 -1 summarizes the demographic characteristics of the areas surrounding the selected sites. Overall, both minority and poverty demographics constitute a slightly larger proportion of the populations surrounding sites with potential SsI threats than the proportion of those demographics in the surrounding counties. For example, poor populations account for 15.4 percent of the population within 1 mile of the average site with potential SsI

31 See Appendix C for the complete demographic screening analysi s, including a population

- weighed estimate that more heav ily weights sites with higher

populations. Due to uncertainty about the location of actual sites, however, we discuss only the unweighted results here.

32 Minority data includes non

- white non

- Hispanics and both white and non

- white Hispanics ; poverty line re fers to the 1999 Federal poverty line.

33 The analysis compared the demographic characteristics of the counties surrounding potentially affected sites to national aver ages to determine whether the

selected counties had a higher proportion of low

- income or minority populations, relative to the cou ntry as a whole. The analysis found that the selected counties had lower proportions of both low

- income and minority populations than national averages but that these differences were not statistically significant.

34 The demographic analysis considered on ly sites potentially affected by the proposed rule where the exact location of the site could be identified.

### 30 

### threats , while the county has a poverty level of 12.3 percent. Exhibit 4-2 provides the results of the statistical analysis of the differences between the one- and three-mile buffer populations and the county population. The
exhibit shows that the difference s within both one and three miles of the sites with potential SsI contamination are statistically significant , as indicated by the p values. For the population within the one- mile buffer, the difference in percent minority population and percent below poverty level with respect to the reference population are significant at the 99 percent certainty level. For the population within the three -mile buffer, the difference in percent minority population is statistically significant at the 95 percent certainty level and the difference in percent below poverty level is significant at the 99 percent certainty. This suggests that the difference between the
valu es is not a random occurrence

.

EXHIBIT 4

- 1. DEMOGRAPHIC CHARA CTERISTICS OF THE PO PULATIONS SURROUNDIN G SITES POTENTIALLY

AFFECTED BY THE PROPOSED RULE

1 MILE 3 MILE COUNTY

MEAN MEDIAN MEAN MEDIAN MEAN MEDIAN

P ercent Minority Population 32.3% 25.0% 30.8% 25. 9% 28. 7% 24.4% Percent Below Poverty Level 15.4% 12.7% 14.2% 12.6% 12.3% 11.1%

EXHIBIT 4

- 2. STATISTICAL ANALY SIS COMPARING DEMOGR APHIC CHARACTERISTIC S OF 1 - AND 3

- MILE

BUFFERS AROUND SELEC TED SITES TO DEMOGRA PHIC CHARACTERISTICS OF SURROUNDING COUNTIES

DIFFERENCE BETWEEN SITE CHARACTERISTICS AND COUNTY CHARACTERISTICS

1- MILE BUFFER 3- MILE BUFFER

MEAN STANDARD

ERROR OF

MEAN TSTATISTIC P- VALUE MEAN STANDARD

ERROR OF

MEAN TSTATISTIC P- VALUE

P ercent Minority Population 0.0366 0.0133 2.75 0.0064 0.0217 0.0103 2.11 0.036
Percent Below Poverty Level 0.0308 0.0063 4.93 < 0.0 01 0.0188 0.0043 4.38 < 0.0 01



### Overall, the demographic analysis identifies a small but statistically significant difference between the proportion of the population that is minority and the proportion of the population in poverty near sites with potential SsI
contamination and in the larger county -level populations . This result implies that any remediation at sites
associated with SsI cont amination would occur in the context of disproportionately high minority and low-income populations located near Superfund sites with potential SsI threats. Because any contingent impacts of the proposed rule would involve risk reduction at these sites, EP A does not anticipate that contingent impacts would have any disproportionately high and adverse human health or environmental effects on these minority or lowincome communities, or on any community. However, because SsI sites have the potential to pose a high level of risk to residents and occupants of other buildings in their vicinity, EPA expects that there will be a realignment and reprioritization of its internal resources to address SsI sites instead of sites without SsI contamination. EPA is

### 31 

### not abl e to predict the location of the sites without SsI contamination or demographic characteristics of populations living nearby

. This section summarizes a screening assessment and does not present a complete environmental justice analysis.The assessment is limited by the fact that demographic data from the U.S. Census are at the block group level, and are not as precise as the spatial distribution of population. As a result, if the demographic distribution of populations within block groups is uneven, the block group- level data may not accurately characterize populations living nearest to sites with potential SsI threats.

In an effort to determine if updated U.S. Census data would identify a reduction in the proportion of the population that is minority or be low the poverty level near sites with potential SsI contamination, the results discussed above based on 2000 U.S. Census data were compared with 2009-2013 American Community Survey (ACS) data

.

EXHIBIT 4

- 3. DEMOGRAPHIC CHARA CTERISTICS OF THE PO PULATIONS SURROUNDING SITES PO TENTIALLY

AFFECTED BY THE PROPOSED RULE

1 MILE 3 MILE

MEAN

(2000 U.S. CENSUS) MEAN

( 2009

- 2013 ACS ) MEAN

(2000 U.S. CENSUS) MEAN

(2009

- 2013 ACS)

Percent Minority Population 41.1% 46.1 % 41.8 % 47.7 %
Percent Below Poverty Level 16.8% 18.8 % 14. 8% 16.4 %



### As was done for the analysis using 2000 U.S. Census data, the analysis first calculate d the proportion of the populations near each site (based on the one-mile and three

- mile buffers) that are minority or below the poverty
level , and t hen compares those proportions. These proportions were then compared to the weighted mean results from the 2000 analysis. Exhibit 4-3 illustrates that the proportion of the population that is minority or below the poverty level near sites with potential S sI threats did not decrease. The refore, the se results continue to indicate that there would not be any expected disproportionate ly high or adverse human health or environmental impacts on these minority or low-income communities.

4.4. Executive Order 13045
– Protection of Children from Environmental Health Risks & Safety Risks

Executive Order 13045 requires that EPA consider whether the proposed rulemaking could result in a disproportionate negative impact on children’s health . As discu ssed in Chapter 3, the proposed rulemaking is expected to have only moderate costs and no direct impact on human health risk. In addition, any impacts resulting from future actions to remediate sites with SsI contamination would reduce the human health ris k at these sites. As a result, EPA concludes that this rule will have no significant impacts on children ’s health.

### 32



### 4.5. Executive O rd er 131 32
– Federalis m

This action does no t have federalism imp lications. It will not have substantial direct effects on the states, on the relationship between the national government and the states, or on the distribution of power and responsibilities among th e various levels of governmen t, as sp ecified in Executive Order 13132, because it does not contain any requirements a pplicable to states or other levels of government. Thus, Executive Order 13132 does not apply to
this action

.
In the s pirit of E xecutive O rder 13132 and consistent with E PA po licy t o promote c ommunications be twee n EPA
and s tate and l ocal g overnments, EPA specifically so licit s comment o n t his proposed a ction from st ate and l ocal
officials

.

4.6. Executive O rd er 13175 – Consultation an d Coordination With Indian T ribal G overnments

This executive order

r equires E PA t o “establish regula r a nd meaningfu l c onsultation and collaborati on w ith tribal
officials in the de velopment of F ederal pol icies that have tr iba l imp lications. ” The ex e cutive order f urther states
th at “ po licies t hat ha v e t

ribal implications” refers to r egulations ; legislativ e c omm ents or p rop osed l egislat ion;
and othe r polic y s tatement s or a cti ons tha t ha v e s ubstantia l e ffect s on one o r m or e I ndian tribes

, on the relationship between t he F edera l G overnme nt a nd Indian tribes, o r on t he d istribution o f pow e r a nd responsibilities between t he F ederal G overnmen t a nd India n tribes.

This pro posed

r u le doe s no t c ontai n a ny r equirement s a pplicabl e to triba l g overnment s and wil l not ha v e a substantia l e ffec t on a ny t ribes

. Thus, t he requiremen ts of t he executive order do n ot a ppl y t o thi s r ulemaking

. In addition, a ny c ontinge nt i mpact s r elate d t o late r listi ng a nd remediation decision s would incl ude a l l c ommunity

outreac h s tipulated unde r C ERCL A a nd existi ng E P A pol ic y t o ensur e c ollaboration wit h t riba l o fficial s f

o r a ny sites on t ribal lan d. Alth ough E x ecutive O rd er 13 175 doe s no t a ppl y t o thi s a ctio n, EPA c onsulted with tribal
official s t hrough meetings ; correspondence, includi ng a l ette r s e nt t o al l f ederall y r ecognize d tribe s aski ng f or

comme nt on t he “Notic e of Opportunit y f or P ubli c I nput ” tha t w a s p ublished i n the Federal R egister on January 31, 2011 (se e 76 F R 53 70) ; a nd publi c l isteni ng s essio ns r egardi ng t he decisi on t o pr oceed wit h t he d evelopment
of thi s a ction.

4.7. Executive O rd er 13211 – Action s t ha t S ignificantl y Affec t E nergy Supply, Distribution, or U sage

This EO r equires federal agenci es to pr epare a “ Statement o f E n ergy E ffects ” w hen undertaki ng c ertai n regulatory
actions. A S tatement of E nergy E ffects describes the adverse effects of a “ significant e nergy a ction ” on e nergy supply, distribution and use

, r easonabl e alternatives to the a ction, and the e xpected ef fects of t he alternatives on

energ y s upply, distributio n and use.

This rulemaking i s not a “ significa nt energ y a cti on.” I t i s not l ikely t o ha ve any ad verse energy i mpacts because
the s ite assessm e nt a ctivitie s a ffecte d by t hi s rul e a r e limited in sc ope and numbe r and rel y on existi ng e nergy distributi on systems. Th e p roposed rul e w ould n ot significantl y e xpa nd t he energ y de mand f or sit e a ssessments,
and would not r equir e a n entit y t o conduc t a ny a cti on tha t w oul d r equir e significan t e nergy use. T he p roposed rule
would hav e no impac t on energ y s upply, distributi on o r us age.

### 33 

### 4.8. Paperwork Reduction Act

According to the Paperwork Reduction Act (PRA), 44 U.S.C. 3501 et seq., an agency may not conduct or sponsor, and a person is not required to respond to a collection of information that requires OMB approval under the PRA, unless it has been approved by OMB and displays a currently valid OMB control number.

This proposed regulatory change will only affect how EPA , and organizations performing work on behalf of EPA (state or tribal partners), conducts site assessments and HRS scoring at sites where certain environmental conditions exist. These conditions involve human exposure from subsurface intrusion of h azardous substances that enter building structures through the subsurface environment either as a vapor or liquid. This proposed regulatory change will result in data collection at these types of sites in order to allow evaluation under the HRS.

EPA expect s that the total number of site assessments performed and number of sites added to the NPL will not increase, but rather expects that there will be a realignment and reprioritization of its internal resources and state cooperative agreement funding. This is because SsI sites have the potential to pose a higher level of risk than other exposure routes, and thus, will allow the agency to evaluate sites with SsI contamination for potential placement on the NPL. The burden for collecting data under the HRS, whi ch includes performance of site assessments, is already covered under the Information Collection Request (ICR) for Superfund Site Evaluation and Hazard Ranking System; EPA ICR No. 1488.08, OMB Control No. 2050-0095, Docket # EPA- HQ

- SFUND

2011- 0052. The inf ormation collection requirements are contained in the statute at CERCLA Section 105(a)(8)(A) under the provisions of the Paperwork Reduction Act, 44 U.S.C. 3501 et seq . and, as mentioned above, has the assigned OMB control number 2050-0095. The OMB control numbers for EPA 's regulations in
Title 40 of the Code of F ederal R egulations (CFR) are listed in 40 CFR 9. Because this proposed rulemaking only involves adding an additional component (i.e., SsI ) to an existing HRS pathway, a new ICR is not needed. Therefore, the agency does not believe this action will impose any new information collection burden, as the term "burden" is defined at 5 CFR 1320.3(b).

4.9. Regulatory Flexibility Act

Pursuant to the Regulator y Flexibility Act (5 U.S.C. 601 et seq., as amended by the Small Business Regulatory Enforcement Fairness Act of 1996), whenever an agency is required to publish a notice of rulemaking for any proposed or final rule, it must prepare and make available for public comment a regulatory flexibility analysis that describes the effect of the rule on small entities (i.e., small businesses, small organizations and small governmental jurisdictions).

This rulemaking does not impose any obligations on any group, including small entities. This proposed regulatory change enables the HRS evaluation to directly consider human exposure to hazardous substances that enter building structures through subsurface intrusion. The HRS is a screening tool that does not impose regulatory requirements on any non-governmental entity. It does not establish any standards or requirements that any small entity must meet, and it imposes no direct costs on any small entity. Whether an entity, sma ll or otherwise, is liable for response costs for a release of hazardous substances depends on whether the entity is liable under CERCLA 107 (a) 35 

### ; therefore, this rulemaking will not impose any further requirements on any small businesses.

35 CERCLA section 107(a) establishes the categories of potentially responsible persons (PRPs) that may be found liable for CERCL A related costs. PRP s include current or past owners and operators, a person who arranges for disposal or treatment of a hazardous substance, and any perso n who accepts hazardous substances for transport to disposal or treatment facilities. PRPs are liable for removal or reme dial response action costs, other necessary costs, natural resource damages, and the cost of health studies conducted pursuant to CERCLA section 9604(i).

### 34 

### 4.10. Unfunded Mandate s Reform Ac t

Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), 2 U.S.C. 1531-1538 requires federal agencies, unless otherwise prohibited by law, to assess the effects of their regulatory actions on state, local, and tribal governments and the p rivate sector. Federal agencies must also develop a plan to provide notice to small governments that might be significantly or uniquely affected by any regulatory requirements. The plan must
enable official s of affected small governments to have meaningful and timely input in the development of EPA regulatory proposals with significant federal intergovernmental mandates and must inform, educate, and advise small governments on compliance with the regulatory requirements.

Th e proposed rule contains no federal mandates (under the provisions of Title II of the UMRA) for state, local, or tribal governments or the private sector. The action imposes no enforceable duty on any state, local or tribal governments or the private sector. Therefore, this action is not subject to the requirements of 202 or 205 of the UMRA. This action is also not subject to the requirements of section 203 of UMRA because it contains no regulatory requirements that might significantly or uniquely affect small governments. Th e proposed reg ulatory change will allow the HRS evaluation to directly consider human exposure to hazardous substances that enter building structures through subsurface intrusion. This addition to the HRS would not impose direct impacts on any other entities.

4.11. National Technology Transfer and Advancement Act

Section 12(d) of the National Technology Transfer and Advancement Act of 1995, Public Law 104– 113, section 12(d) (15 U.S.C. 272 note), directs EPA to use voluntary consensus standards in its regulatory activities unless to do so would be inconsistent with applicable law or otherwise impractical.

This rulemaking will not involve technical standards; therefore, EPA will not consider the use of any voluntary
consensus standards.

### 35 

### 5. Summary of Costs, Benefits and Other Impacts

This chapter documents the comparison of costs and benefits associated with the proposed rule, and addresses U.S. Environmental Protection Agency ( EPA ) and Office of Management and Budget ( OMB ) re quirements that regulatory impact analysis consider cost

- effectiveness of regulations and alternative discount rates.

5.1. Cost Benefit Comparison

Regulatory impact analyses typically use a formal cost

- benefit analysis to assess the impacts of proposed rulemakings. Due to the limited scope of the proposed amendment to the regulations at Title 40 of the Code of

F ederal R egulations (CFR) 300.425, the analysis considers only the cost impacts of considering subsurface intrusion ( SsI ) threats in site assessments and does not develop a quantitative estimate of benefi ts. The results of the analysis of the costs and benefits of the proposed rule are summarized in Exhibit 5-1. As the exhibit shows, total annual costs of Option 2 (the preferred option) are expected to range from $0.7 million to $ 1.4 million. Total annual costs in all scenarios are less than $ 4 million. Because the Regulatory Impact Analysis does not quantitatively estimate benefits, a formal quantitative comparison of the expected costs and benefits of the proposed rule is not possib le. However, Option 2 has been selected as the preferred option as it is consistent with
the 1990 Hazard Ranking System ( HRS ) , serve s as an effective screening tool that would both minimize unnecessary resource expenditures and the erroneous inclusion or exclusion of sites from possible placement on the NPL, and is based on proven science.

EXHIBIT 5- 1. SUMMARY OF COSTS AND BENEFITS (MILLION$)

TYPE OF IMPACT OPTION 1 OPTION 2
(PREFERRED

OPTION) OPTION 3

Costs

Annual Costs of Investigating SsI threats and of Preparing HRS Packages for SsI sites (million 2011$)

High

- End Scenario $ 1.0 $ 1.4 $ 2.9

Best

- Estimate Scenario $ 0.5 $ 0.7 $ 1.6

Benefits
Improved quality of information and more effective prioritization of remedial efforts by the Superfund program through a more comprehensive characterization of sites with SsI threats. Not quantifiable

Note : Because cost impacts are expected to be constant on an annual basis over time, presenting the net present value of costs would not add analytic value and are not presented here. Therefore, although alternative discount rates of seven percent and three pe rcent were not considered, the costs presented in this exhibit satisfy OMB Circular A

- 4 and EPA policy requirements to annualize regulatory impacts using alternative discount rates of seven percent, three percent and zero percent (undiscounted).

### 36 

### 5.2. Other Required Analyses

OMB Circular A

- 4 directs Federal agencies to support rulemakings with cost

- effectiveness analysis wherever possible and to consider costs and benefits under alternate discount rates of three percent and zero percent (i.e., no discounting).

• Cost

- Effectiveness Analysis : Because the expected benefit of the proposed rulemaking is an improvement in the overall efficiency of the Superfund program, there is no unit measure of benefit that
could be used to conduct a cost

- effectiveness analysis.

• A ssessment of Costs and Benefits under Alternative Discount Rates : Because cost impacts are presented on an annual basis, the analysis does not estimate present value of costs. The costs presented in
Exhibit 5

- 1 therefore satisfy OMB Circular A -4 and EPA po licy requirements to annualize regulatory impacts using alternative discount rates of seven percent, three percent and zero percent (i.e., undiscounted).

### A- 1 

## APPENDIX A: Options Sel ection Matrix

EXHIBIT A -1 . FULL COMPARISON OF OPTIONS CONSIDERED F OR THE PROPOSED RULE 36

OPTIONS FOR SCORING POPULATIONS POTENTIAL NUMBER OF NPL CALIBER

INTRUSION SITES PROS/CONS CONSISTENCY WITH OTHER HRS PATHWAYS POPULATIONS NECESSARY TO QUALIFY A SITE FOR THE NPL

Option 1
– Consider Only Actual and Inferred Exposures

• Includes all actual and inferred contamination for regularly occupied
structures within the AOE

• Does not include potential exposure for regularly occupied structures outside
the AOE Les s Pro: Will have a high probability that identified releases pose a risk when scoring by zones of contamination

Co n: Could fail to identify sites warranting further investigation because potential exposures will not be considered

Con: Does not consider future conditions/migration and may necessitate greater review of sites given a “no further action” designation Op tion is consistent with:

• The soil exposure pathway in that it does not consider potential targets and infers Level
II contamination

• All pathways in how Level I and II targets are weighted • 23 people actually exposed to contamination above
Health

- Based Benchmarks (Level I in the AOE ), or

• 10 people actually exposed to contamination above
Health

- Based Benchmarks (Level I) an d 130 people actually exposed to or inferred to be exposed to contamination above background (Level II), or

• 231 people actually exposed to or inferred to be exposed to contamination above background (Level II in the
AOE )

Assu mes a Waste Characteristics v alue of 32

Option 2
– Consider Actual, Inferred and Probable Exposures

• Includes those regularly occupied structures within
the AOE and the ASC

• Includes both actual contamination intrusion and probable exposure to subsurface contamination for regularly occupied
structures within the AOE
and ASC Mid dle P ro: Would ensure that most releases posing a significant risk are identified by relying upon lines of evidence

Co n: Could lead to an underestimate of the number of releases because future migration of subsurface contamination is not accounted for and/or because lines of evidence gathered during the Site Assessment process may be incomplete

Co n: Does not consider futur e conditions / migration; therefore, may necessitate greater review of sites given a “no further action “ designation Op tion is consistent with:

• The soil exposure, air and surface water pathways in that there is inference of contamination for Level II tar gets

• The air pathway in that
“on

- source” targets are included in the scoring

• All pathways in how Level I and II targets are weighted • 23 people exposed to contamination above Health

- Based Benchmarks (Level I in the AOE ), or

• 10 people exposed to contamination above Health

- Based Benchmarks (Level I) and 130 people exposed to contamination above background (Level II), or

• 231 people exposed to contamination above background (Level II in the AOE ), or

• 10 people exposed to contaminat ion above Health

- Based Benchmarks (Level I) and 100 people exposed to contamination above background (Level II) (in AOE ) and
36 people living above subsurface contamination (Probable Exposure in ASC ), or

• 548 people living above subsurface contamination (Probable Exposure in ASC ) assuming a Likelihood of Exposure of 500

Assumes a Waste Characteristics Value of 32 and a weighting of 0.5 for Probable Exposure Populations

36 The methodologies used to evaluate the waste characteristics and targets factor category values in t he proposed HRS addition have been revised since these three options were created to model d ifferent scoring

scenarios. Please see the preamble, rule, and technical support document for the proposed HRS addition for additional informa tion.

### A- 2 Option 3
– Consider Actual, Inferred, Probable and Potential Exposures

• Includes regularly occupied
structures within the AOE

, the ASC and the PMZ

• Includes actual contamination intrusion, probable and potential exposure to subsurface contamination for reg ularly occupied structures within
the AOE

, ASC and PMZ

• Includes unsampled structures, but are considered to be potentially exposed Mo s t Pro: Would ensure that all releases posing a risk are identified

Con: Could result in identification of low risk releases because not all identified releases will result in future

exposure

Con: Limited rationale for projecting extent of potential migration zone

Con: Not assuming migration in all directions (i.e., <360 de grees) could result in questioning the target delineation for ground water and air pathways Op tion is consistent with:

• The air pathway in that
“on

- source” targets are included in the scoring

• The ground water pathway in that the

way PMZ targets are weight ed

• All pathways in how Level I and II targets are weighted • 23 people exposed to contamination above Health

- Based Benchmarks (Level I in the AOE ), or

• 10 people exposed to contamination above Health

- Based Benchmarks (Level I) and 130 people exposed to contamination above background (Level II), or

• 231 people exposed to contamination above background (Level II in the AOE ), or

• 10 people exposed to contamination above Health

- Based Benchmarks (Level I) and 100 people exposed to contamination above background (Level II) (in AOE) and
36 people living above subsurface contamination (Probable Exposure in ASC ), or

• 548 people living above subsurface contamination (Probable Exposure in ASC ) and assuming a Likelihood

o f Exposure of 500, or

• 21,962 people living in an area where subsurface migration could occur (Potentially Exposed People in the
PMZ ) and a Likelihood of Exposure of 320

Assumes a Waste Characteristics value of 32, a weighting of 0.5 for Probable Exposure Populations and 0.02 for Potentially Exposed Populations



## De finitions of Zones

Area of Observed Exposure (AOE)
– An area of observed contamination; the AOE 

### is bounded by regularly occupied structures with documented contamination intrusion above background; the AOE 

### includes sampled and unsampled structures, which are assumed to be contaminated, and only actually exposed populations. 23 

### Represents people subject to Level I contaminant concentrations. Represents people subject to Level II contaminant concentrations.
Area of Subsurface Contamination (ASC)
– An area with documented contamination significantly above background; the ASC 

### is bounded by sampling points meeting
observed release criteria for subsurface intrusion (e.g., ground water and soil gas sampling points) ; the area within the ASC 

### includes both sampled and unsampled structures and probable exposure populations; the ASC 

### do es not include the AOE



### .

Potential Ground Water Migration Zone (PMZ)
– An area between the ASC 

### and target distance limit that includes all occupied structures; occupied structures may be unsampled, but populations are potentially exposed to intrusion currently or in the future given the proximity to the source and future migration of the ground wate r or soil gas contamination plume; the PMZ does not include the AOE 

### or the ASC



### .

### B-1 

## APPENDIX B: Conceptual Site Model Used to Estimate Costs of Screening for Su bsurface
Intrusion Contamination

This appendix describes the conceptual site model (CSM) used to estimate the costs of the proposed addition of a subsurface intrusion (SsI) component to the Hazard Ranking System (HRS). It first presents a discussion of the data sources, methods and assumptions used to devel op the base case CSM written in support of the proposed rulemaking. It then describes adjustments made to the CSM in order to exclude outlier cost estimates and compare the costs of the preferred regulatory option and two alternate options.



## SsI Site Inspection Cost Estimate Introduction

The U.S. Environmental Protection Agency (EPA) is proposing the addition of an SsI component to the HRS. Subsurface intrusion is the result of contaminated subsurface soil or ground water plumes releasing contaminants into occupied structures, mainly as a gas or vapor. This rulemaking will enable EPA to evaluate sites where SsI contamination poses a potentially significant threat to human health using t he HRS, thereby fulfilling the a gency’s obligations to protect human health.

Determining the costs associated with evaluating SsI threats as part of the site assessment process is necessa ry in order to better understand the financial impacts the proposed rule represents. To this end, EPA prepared a survey for the purpose of evaluating the cost of performing a site inspection (SI), including typical sampling/screening techniques used for ev aluating SsI threats. The survey, which included instructions to develop cost estimates for particular SI tasks, was submitted to each of EPA Regions on the HRS/SsI work group, an EPA Regional contractor (Tetra Tech Incorporated) and the U.S. Army Corps of Engineers (USACE). 37



### The primary objectives of this survey and subsequent analysis of provided cost estimates were to: (1) estimate the unit costs for conducting specific tasks (e.g., installing a sub- slab vapor probe) related to investigating a site fo r potential SsI threats and (2) use unit cost information to estimate the total cost for conducting an SI to evaluate SsI. This preliminary cost estimate was developed using cost data provided in response to the survey and was based on previous site assess ments. Data obtained from the survey should be considered only for estimation purposes as investigation costs can vary greatly depending on the scope of work performed, which is a function of geographic location, geologic setting, nature/extent of contamination and demographics, along with numerous additional factors. It should also be noted that, although the survey requested cost information for performance of an SI, such investigations can include a level of effort associated with an expanded site inspec tion. The cost information gathered was used to project the estimated cost of an assessment to evaluate SsI threats using a conceptual site model as described in this document.

37 Cost information for conducting an SI of a site with vapor intrusion contamination was requested from the data sources. For t he purposes of this analysis, the

more general term, subsurface intrusion, was used instead of vapor intrusion to refer to the com ponent proposed for addition to the HRS. The costs for a vapor intrusion SI would likely be more expensive than that for a typical site with ground water intrusion into structures.

### B-2 

## Data Sources

Survey data were received from EPA Regions 3, 5 and 6 and an EPA contractor, Tetra Tech Incorporated (Tetra Tech), through Dave Bartenfelder of EPA Headquarters, and a representative of USACE’s Baltimore District. Additionally, costs associated with data validation were obtained from several EPA Regions who supplied estimates based on validation work performed by an agency contractor. Cost estimates from Tetra Tech and USACE were considered primary sources, with estimates from EPA Regions used for purposes of comparison
and verification when unable to calculate task unit costs from the data provided. Please refer to Appendix D: Costs for Vapor Intrusion Site Inspection Tasks Compiled for Regulatory Impact Analysis for additional details. Throughout this section, cost estimates that appear to be outliers (i.e., that d iffer substantially from estimates provided by other data sources) are highlighted. When applying the CSM to the cost analysis in the Regulatory Impact Analysis ( RIA ), EPA decided on a case -by- case basis whether to exclude these outliers from the total SI cost estimate. The full treatment of outliers is discussed below in the section describing how the CSM was adjusted for use in the RIA.

U.S. EPA Regional Cost Data

EPA Region 3 provided cost summaries that contained unit and/or total costs from three pre vious site assessments for the following tasks: in -house preparation, field sampling and analysis, report preparation, travel and per diem. This included discrete costs for materials and labor for probe construction, as well as labor costs for what was

ass umed to be preparation of Summa canisters. The field sampling and analysis costs included unit costs for Summa canisters (assumed to be analytical costs), labor costs and shipping costs. Cost data for project planning (except for one site where costs for a health and safety plan and a work plan were provided), mobilization fees and equipment rental costs were not reported. Quality assurance/quality control costs of $100 per sample listed under the “Report” section of the provided cost summaries were assumed to be data validation costs.

• Data Outlier: This dataset contained a cost estimate of $600/sample for Summa canister analysis, which appears to be an ou tlier. This unit cost resulted in the significantly higher cost of $45,600 to analyze 76 Summa canister samples (see Exhibit B-6).

EPA Region 6 provided cost summaries for four previous field investigations that contained total costs for the following ta sks: planning, equipment rental, field supervision, project management and incidental costs. The data for one investigation stated that the total cost of collecting 12 Summa canister samples was included in these costs. The total costs for installing expos ed screen monitoring wells were provided, but not a breakdown of their associated equipment, materials, or labor costs. Costs related to collecting ground water monitoring well samples were not provided. Additional costs provided were material and analytic al unit costs for passive diffusion samplers. Costs relating to data validation activities were not provided and were assumed to be included in analytical costs provided.

• Data Outlier : The costs provided for field supervision (range of $20,500-$35,308), project management (high cost of $17,600) and incidental costs (high cost of $11,226) are potentially higher compared to those of other source estimates, and may include some unrelated costs (see Exhibit B-1).

### B-3 

### EPA Region 5 provided more limited information on the total costs of collecting an individual indoor air, ambient air, sub -slab and soil gas sample from previous investigations, and did not include any discrete planning, staging, oversight or reporting costs. These cost estimates did not break out t he individual components for labor, equipment and materials used, but the information provided was compared to the more detailed data obtained from other sources to verify that costs were similar.

Data validation cost estimates, which reflected validatio n work performed by contractors (as opposed to EPA in

house), were also obtained from representatives at several EPA Regional laboratories. All costs were provided on a “per sample” basis, reported separately for differing media (air versus water) and, to the extent practicable, took
into account whether a streamlined or full

- level quality assurance (QA) review was conducted. For the most part, unit costs were higher than those estimated by USACE, which assumed streamlined QA review, and Tetra Tech, whose Q A costs were low even for streamlined review.

• Data Outlier : The costs provided by EPA Region 1 for a streamlined QA review ($202 per sample) and a full QA review ($275 per sample) of water sample data appear to be outliers compared to the information

rec eived from other EPA Regions. In addition, the data validation costs received from EPA Regions ($39- $115 per sample for air and $19-$275 per sample for water) are greater than the costs provided by Tetra Tech ($10-$17 per sample for air and $10- $15 per sample for water) and USACE (assumed $27.82 -$30 per sample for both air and water). This cost differential results in higher data validation costs when using

EPA Regional estimates (see Exhibit B-6).

U.S. EPA Contractor Cost Data (Tetra Tech)

Cost estimates for all of the tasks listed in this cost survey were received from Tetra Tech. Their estimates were based on previous experience and recent bids and quotes. If they received more than one bid for a task, the most reasonable bid, based again on their experience, was selected. For the most part, except where noted in the following tables, the unit and total costs provided for each task included labor, equipment and material costs (but not shipping). Data validation costs for SW-846 method 8260 analysis (water or soil -gas) and for EPA method
TO

- 15 analysis (soil -gas or indoor air) were also obtained. The cost estimates were based on an assumed quantity of samples and timeframe needed to accomplish a particular task. Certain tasks listed in the Te tra Tech summary included a range of unit and/or total costs, which was the result of the assumed number of samples and estimated
timeframe utilized.

It was also noted by Tetra Tech that “Target Identification” data requested in the cost survey was cover ed by thepre-sampling building survey task shown in Exhibit B-5. The estimated cost provided for conducting a presampling building survey was $1,000/day in labor costs covering one industrial building or eight residential buildings per day.

• Data Outlie r : The data included cost estimates for certain tasks that were noted as being highly variable and based on such factors as the size/complexity of the site, the seniority and number of crew members, the location of the site and the scope/duration of the pr oject. Two tasks in particular, planning and project management, had costs showing especially large ranges ($10,000- $100,000 and $10,000 -$80,000 respectively), where the high estimates appear to be an outlier (see Exhibit B -1). The data provided also
inclu ded a separate “Reporting” task that contained a cost range of $10,000 - $100,000 that was not

### B-4 

### included in this cost analysis as a line item due to the wide variability in the Tetra Tech costs already present. These three outliers also potentially represen t costs associated with site investigations that are beyond the scope of a typical site inspection for HRS purposes.

U.S. Army Corps of Engineers Cost Data

The data provided by the USACE included unit and total costs for all tasks listed in this cost analysis and were based on previous experience, future projects and internet research for a “typical number of sites.” The estimated unit costs typically included the relevant equipment, material and labor cost components for each task listed in this analysis . Unlike in the data provided by Tetra Tech and EPA Region 3, the only cost associated with collecting a Summa canister sample was the labor to set up, collect and ship (shipping costs were included in incidental costs) the resulting samples. The material and preparation costs for Summa canisters were included in the analytical costs, in contrast to data obtained from Tetra Tech and EPA Region 3, which included these costs as part of sample collection. Data validation costs were also obtained for SW

- 846 met hod 8260B. The USACE provided cost estimates for conducting a pre-sampling building survey that was based on labor costs for two people (1/2 day) for 5-15 locations and a unit cost of $600. The USACE also provided estimated total costs for collecting “Targ et Identification” information.

• Data Outlier: The cost provided for conducting a pre- sampling building survey was significantly greater than the estimated cost provided by Tetra Tech ($600/residence vs. $1,000 per day to sample up to 8 residences) (see E xhibit B -5).



## Data Analysis

Cost data were used to estimate a unit cost (e.g., per sample or per well) for performing a particular task. The data received from the aforementioned sources were used to calculate the range, median and mean cost values for
individual tasks that could be used in an SsI investigation. If the unit cost was not provided, it was extrapolated by assuming uniformity between total cost and total number of units. For example, if 10 wells were installed for a total cost of $18,000, a unit rate of $1,800/well was projected.

In conducting this analysis, because the data received were often in different formats, assumptions were made, as needed, regarding what the provided costs included and into which tasks they appeared to best fit. Additionally,
unit rates were of ten calculated based on information assuming a minimum number of units; therefore, unit prices may differ depending on the number of samples required at a particular site (i.e., economies of scale). For example, the range in unit costs provided by Tetra Tech for collecting sub- slab samples using batch certified Summa canisters (see Exhibit B- 4) were based on the total costs for collecting 25 samples at residences with basements, 15 samples at residences with enclosed crawl spaces and 10 samples at residences without basements (e.g., slab-on- grade). Although the daily labor rate and equipment and material costs at each type of sampling location were the same, the unit costs ranged from $270-$370 per sample due to the differences in the number of days needed t o collect the assumed number of samples.

This CSM analysis assumes the collection of 32 samples (including two background locations); divided equally
between residences with basements and those constructed with a slab -on-grade foundation). For the purpos es of this analysis, the unit costs derived from the above data sources were used to calculate the estimated total costs to

### B-5 

### the USACE, EPA and an EPA contractor of conducting an SI for SsI. Therefore, the estimated low ($270/sample) and high costs ($370/sample) for collecting one of the 32 sub- slab Summa canister samples were calculated based on the aforementioned unit costs and not the specific cost of collecting 32 samples. Extrapolating total costs below the minimum number of units required for a task ma y underestimate per unit costs, as there are minimum costs associated with some of these tasks. For example, the mean unit rate for collecting a single Tedlar bag indoor air quality sample was calculated to be $55; however, the labor to mobilize to the site and deploy a single sample is likely much higher.



## Conceptual Site Model

To project the cost of an assessment to evaluate SsI threats, the unit costs provided by EPA Regions, Tetra Tech and USACE were applied to a CSM . It is assumed that only SsI is being evaluated as part of the site assessment process and that the level of effort entailed would be sufficient to determine whether a site would likely qualify for placement on the National Priorities List. Furthermore, the CSM is based on the assumption t hat a minimum of 25 residences are present on or adjacent to the site and reflects the most common waste characteristics scoring values used at sites evaluated under the current HRS. Finally, it is assumed that sufficient staff would be available
to conduc t all on

- site SI activities in one site vi sit covering a four -day period.

General Site Description

The site is in an old industrial area on the outskirts of an urban area. The site is the location of a release of chlorinated solvents from a facility that used solvents during various stages of production to prepare the product for further processing. On the facility are solvent storage tanks with varying amounts of solvents, abandoned drums of waste solvents and at least one surface impoundment. Contaminated soil areas at the facility have been
identified in and around these units. A 35- acre residential/commercial area is adjacent to and hydrologically downgradient of the facility, with approximately 50 residences, small stores and restaurants.

Geologic Setting

The site is located in a relatively flat area. The original surface soil is a sandy loam, but at least 60% of the land surface is covered by structures, roads and other impervious surfaces. The subsurface soil has a depth of 30 to 40 feet and is silty sand with fingerings of clay lenses. Depth to ground water varies between 10 and 15 feet. The

str atum below the silty sand is fractured sandstone.

Known Extent of Contamination

Based on preliminary sampling, contamination significantly above background has been estimated based on four monitoring wells to extend below 70% of the residential/commercia l area. Limited sampling in the rest of the area indicates sporadic chlorinated solvent contamination above detection limits. Soil gas sampling indicates
detectable contamination in a subarea that encompasses about 25 residences. Passive diffusion sampling results (i.e., contamination in subsurface below structures) suggests subsurface intrusion could occur in 15 homes; the other 10 residences have not been sampled.

### B-6 

### Demographics

The ground water in the area is not used as a drinking water supply. Based on real estate listings, the residences are mainly three -bedroom homes, averaging 1800 square feet; 50 percent have basements, 25 percent have enclosed crawl spaces and the rest have concrete slab foundations. A day care center servicing seven children has been documented at one of the residences. The county average population per household is 2.6. There are at least five commercial structures but they have not been canvassed or sampled.



## Estimated Site Inspection Costs to Evaluate SsI Threat

Because ground water does not represent a current or potential drinking water source, cost estimates have been generated assuming SsI as the only pathway being evaluated. A scope of work was developed using previously utilized methods for addressing an SsI threat and the following data tables provide low and high value cost estimates for conducting site assessment activities based on the cost survey described earlier. If only one cost estimate for a task was derived from the data provided, the value was repeated in the high cost column. It was assumed sufficient staff and resources would be available to complete on

- site SI activities in four days.

Planning, Staging, Oversight and Reporting

Costs associated with planning, staging, oversight and reporting varied greatly, as expected, depending on the scope of work and nature/extent of the site evaluation. The travel, per diem and shipping costs provided by EPA Region 3 were consolidated under the “Incidental Costs” task and the reporting costs were consolidated under the “Project Management, Oversight and Reporting” task in Exhibit B -1. EPA Region 3 did not provide costs relating to planning (except for one site where costs for a health and safety plan and work plan were provided), mobilization fees and equipment rental costs. Data received from the USACE included information that enabled the calculation of daily rates for certain Exhibit B

- 1 tasks, with the remaining tasks left defined with per

investigation costs. Tetra Tech provided either daily or per

- investigation rates for relevant tasks.

### B-7 EXHIBIT B

- 1. COST RANGES FOR C ONDUCTING PLANNING, STAGING, OVERSIGHT A ND REPORTING

ACTIVITIES FOR AN SS I SITE INSPECTION

TASK USACE LOW ESTIMATE ($) USACE HIGH ESTIMATE ($) TETRA TECH LOW ESTIMATE ($) TETRA TECH HIGH ESTIMATE ($) EPA REGIONS

LOW ESTIMATE ($) EPA REGIONS

HIGH ESTIMATE ($)

Planning costs based on previous projects of similar size and scope 5,000 10,000 10,000 * 100,000 * 3,000 5,900

Project mobilization fees (e.g. Geoprobe ® ) 3,000 3,000 1,000 1,000 N/A N/A

General equipment rental costs based on previous projects of similar size and scope 4,000 ** (1,000/day) 4,000 ** (1,000/day) 400 ** (100/day) 2,000 ** (500/day) 528 1,055

Field supervision (e.g., well logging, field

screening and drilling supervision costs) 8,000 ** (2,000/day) 8,000 ** (2,000/day) 2,000 ** (500/day) 8,000 ** (2,000/day) 20,500 35,308

Project management, oversight and reporting costs based on previous projects of similar size and scope 10,000 10,000 10,000 * 80,000 * 8,000 17,600

Incidental costs (e.g., travel, mileage, shipping) based on previous projects of similar size and scope 4,000 4,000 100 ** (25/day) 2,000 ** (500/day) 3,765 11,226

Task subtotal 34,000 39,000 23,500 193,000 35,793 71,089
* Cost estimates provided by Tetra Tech for these tasks were stated to be highly variable depending on such variables as the composition of

the crew and the size/complexity of the site being investigated. ** Denotes task costs that are based on a daily ra te. All other Exhibit B

- 1 values represent the cost for a single investigation. N/A refers to data not provided but assumed to be included in other Exhibit B

- 1 tasks within the same information source.



### Ground Water Characterization

To further delineate the horizontal extent of ground water contamination, it was projected that a minimum of eight monitoring wells throughout the plume and surrounding residential neighborhood would be required. Utilizing the four existing monitoring wells, an additional four temporary, exposed screen wells would be installed using direct push technology (e.g., Geoprobe ® 

### ). Because background contaminant levels are necessary to correlate contaminant association with the site, two additional temporary, exposed screen wells would be installed up

gradient from the source, resulting in a total of six newly installed wells.

### B-8 EXHIBIT B

- 2. GROUND WATER WELL INSTALLATION AND SAM PLING COSTS

TASK USACE LOW ESTIMATE ($) USACE HIGH ESTIMATE ($) TETRA TECH LOW ESTIMATE ($) TETRA TECH HIGH ESTIMATE ($) EPA REGIONS

LOW ESTIMATE ($) EPA REGIONS

HIGH ESTIMATE ($) Installation of six temporary exposed screen monitoring wells utilizing direct push technology (USACE and
EPA Region 6 provided total costs; Tetra Tech provided equipment, material and labor costs) 6,000 9,000 8,160 8,760 3,648 5,328

Sample collection from the six newly installed temporary monitoring wells (USACE provided equipment, material and labor costs; Tetra Tech provided labor costs) 2,400 2,400 1,200 1,200 1,800 * 1,800 *

Sample collection from the four existing monitoring wells (USACE provided equipment, material and labor costs; Tetra Tech provided labor costs) 1,600 1,600 800 800 1,200 * 1,200 *

Task subtotal 10,000 13,000 10,160 10,760 6,648 8,328
* Cost estimates for sample collection were not provided by EPA Regions; therefore, the median of all received cost estimates was used in this analysis.



### Soil G as Characterization

To characterize the extent of soil gas contamination, it was projected that a minimum of 10 soil gas samples within the residential neighborhood and suspected contaminated ground water plume would be required to evaluate the SsI threat. Soil gas samples wo uld be installed using direct push technology. Two soil gas samples would need to be collected from locations up-gradient from the source and outside of the zone of influence, resulting in a total of 12 soil gas samples being collected. The use of Summa ca nisters in conjunction with the direct push methods would be employed to collect the samples.

EXHI BIT B

- 3. SOIL GAS SAMPLING COSTS

TASK USACE LOW ESTIMATE ($) USACE HIGH ESTIMATE ($) TETRA TECH LOW ESTIMATE ($) TETRA TECH HIGH ESTIMATE ($) EPA REGIONS

LOW ESTIMATE ($) EPA REGIONS

HIGH ESTIMATE ($) Collection of 12 soil gas samples utilizing direct push technology (USACE provided equipment, material and labor costs; Tetra Tech provided equipment and labor costs) 3,996 4,800 1,860 2,520 3,264 * 3,264 *

Task subtotal 3,996 4,800 1,860 2,520 3,264 3,264

* This sample collection method was not utilized in the examples provided by EPA Regions; therefore, the median of all other received cost estimates was used in this analysis.



### Sub-Slab Vapor Characterization

To e valuate vapor concentrations beneath homes within the identified residential neighborhood, it was determined that the 25 residences suspected to be impacted based on earlier passive soil

- gas assessments represented the greatest threat . Temporary sub -slab vapor points would be installed in each of these structures using hand-held

### B-9 

### roto-hammer methods. An additional five points would be installed in other structures within the neighborhood and along the suspected ground water plume bounda ry. It was assumed that approximately 50 percent of the
residences where sub

- slab vapors are sampled have basements and the remaining 50 percent are slab -on- grade construction. All basements were assumed to have concrete floors. Two occupied structures of similar construction (i.e., one basement and one slab-on- grade) and socioeconomic status, and located up- gradient of the source and outside of the zone of influence, would be needed to establish background sub -slab contaminant concentrations. Temporary sub -slab vapor points would be installed in each of these locations as well. Sampling from each of the 32 residences would be conducted using Summa canisters and 24-hour sampling periods.

EXHIBIT B

- 4. SUB

- SLAB SAMPLING COSTS *

TASK USACE LOW ESTIMATE ($) USACE HIGH ESTIMATE ($) TETRA TECH LOW ESTIMATE ($) TETRA TECH HIGH ESTIMATE ($) EPA REGIONS

LOW ESTIMATE ($) EPA REGIONS

HIGH ESTIMATE ($) Installation of 32 temporary sub

- slab vapor points utilizing hand

- held roto

- hammer methods (USACE and Tetra Tech provided equipment, material and labor costs; EPA Region 3 specified labor costs) 9,600 9,600 3,360 4,480 5,600 8,000

Sample collection from the 32 newly installed sub

slab vapor points utilizing Summa canisters and
24

- hour sampling periods (USACE provided labor costs; Tetra Tech and EPA Region 3 provided Summa canister preparation costs and labor) 4,800 4,800 8,640 11,8 40 3,232 11,360

Task subtotal 14,400 14,400 12,000 16,320 8,832 19,360

* Assumes sub

- slab vapor points (including the background location) would be installed in 16 homes with basements and 16 with slab

- on

grade construction.



### Indoor Air Characterization

To evaluate indoor air vapor concentrations within the residential neighborhood, it was determined that comparative values between sub -slab and indoor air concentrations represented the best method for evaluating the SsI threat. A total of 32 indoor air q uality samples utilizing Summa canisters and 24 -hour sampling periods would
be collected from the same homes where a sub -slab sample would be collected, including from the two homes considered to be background. EPA Regional costs estimates did not include costs for conducting pre-sampling building surveys; therefore the cost estimates provided by Tetra Tech of $1,000 in labor costs to survey up to eight residential buildings per day was used. This information, instead of the median cost for this task from a ll sources, was used as it was provided by an EPA contractor. Cost estimates for conducting a separate background indoor air quality sampling event were also provided by Tetra Tech but, as the equipment and labor costs were
similar to the costs for collect ing indoor air samples, these costs were not used. The USACE provided unit and total costs for conducting a pre-sampling building survey that included unit costs of $600 per structure (2 people for 1⁄2 day) and typical past total costs of $10,000 for up to 15 structures. For the purposes of this cost model, it was assumed the best approach would be to calculate the cost of surveying 32 structures based on the unit cost provided.

### B- 10 EXHIBIT B

- 5. INDOOR AIR SAMPLI NG COSTS

TASK USACE LOW ESTIMATE ($) USACE HIGH ESTIMATE ($) TETRA TECH LOW ESTIMATE ($) TETRA TECH HIGH ESTIMATE ($) EPA REGIONS

LOW ESTIMATE ($) EPA REGIONS

HIGH ESTIMATE ($)

Pre

- sampling building survey (labor costs) 19,200 19,200 4,000 4,000 4,000 * 4,000 *
Sample collection from 32 homes utilizing Summa canisters and 24

- hour sampling periods (USACE provided labor costs; Tetra Tech and
EPA Region 3 provided Summa canister preparation costs and labor) 4,800 4,800 9,920 9,920 3,232 11,360

Task subtotal 24,000 24,000 13,920 13,920 7,232 15,360

* Estimated costs for this task were not received from EPA Regions; therefore, the estimated unit cost provided by Tetra Tech, an EPA

contractor, was used.



### Labor atory Analysis

Based on a review of the cost data received for this analysis, the use of Summa canisters and EPA method TO -15 analysis for volatile organic compounds (VOCs) appears to represent the most commonly employed approach for collection and analysis of air sample s. EPA SW -846 method 8260B Modified represents a widely accepted method for analysis of ground water samples. It was assumed that, although the analytical method was not cited in the information submitted by EPA Region 3 for prior investigations, EPA metho d TO -15 was used for the analysis of air samples. The estimated unit costs provided by eight EPA Regions for data validation of air (six Regions) and water (eight Regions) samples were for unknown, variable, streamlined and full levels of review. For the p urposes of this analysis, the low and high unit costs of all levels of review were used to calculate the total
cost of data validation.

EXHIBIT B

- 6. ANALYTICAL COSTS

TASK USACE LOW ESTIMATE ($) USACE HIGH ESTIMATE ($) TETRA TECH LOW ESTIMATE ($) TETRA TECH HIGH ESTIMATE ($) EPA REGIONS

LOW ESTIMATE ($) EPA REGIONS

HIGH ESTIMATE ($)

Laboratory analysis of 10 ground water samples using EPA method 8260B Modified. 1,000 1,000 850 850 930 ** 930 **

Laboratory analysis of 76 Summa canister samples using EPA Method TO

- 15 (12 soil gas, 32 sub

- slabs and 32 indoor air quality). 19,000 19,000 12,540 12,540 19,000 45,600

Data validation (86 samples). 2,393 2,580 1,012 1,442 3,154 * 11,490 *

Task subtotal 22,393 22,580 14,402 14,832 23,084 58,020
* Estimated unit costs were derived from per sample costs (air and water media) received from eight EPA Regional offices and costs provided by EPA Region 3 for three previous investigations. It was assumed that data validation costs for investigations prov ided by Region 6 were included in their method analytical costs. ** This analytical method was not utilized in the examples provided by EPA Regions; therefore, the median cost of all other received estimates was used in this analysis.

### B- 11 

### Target Identification

Th e survey used to solicit cost data for performing various tasks associated with conducting an SsI evaluation included a request for estimated costs to identify the composition and use of occupied structures and the number of people living or working within each. Tetra Tech stated that this information was covered by their presampling building survey ( Exhibit B -5) and EPA Regions did not provide this information. The USACE provided cost ranges for each task, where the lower value reflects targets or properties located entirely on federal property.

EXHIBIT B- 7 – TARGET IDENTIFICATIO N

TASK USACE LOW ESTIMATE ($) USACE HIGH ESTIMATE ($) TETRA TECH ESTIMATE ($) EPA REGIONS ESTIMATE ($) Identify structure composition for each property within the target area (e.g., basement, slab

- on

- grade). 1,000 15,000 Covered in Exhibit B

- 5
Pre- sampling building

survey Not provided

Identify property use characteristics for each property within the target area (e.g., residence, retail, office, school). 1,000 5,000 Covered in Exhibit B

- 5
Pre- sampling building

survey Not provided

Quantify the number of human targets per property (e.g., field verify how many people live at each residence?

year

- round?). 5,000 15,000 Covered in Exhibit B

- 5
Pre- sampling building

survey Not provided

Task subtotal 7,000 35,000 N/A N/A
N/A refers to either this task being covered by another task or data not having been provided.



### Es timated Total SsI Site Inspection Costs

Ba sed on the scope of work and tasks outlined above, the following estimated totals for conducting a site assessment where SsI is the primary pathway being evaluated were calculated based on available data:

EXH IBIT B

- 8 - TOTAL ESTIMATED SITE INSPECTION COSTS FOR SUBSURFACE INTRUSION

USACE LOW ESTIMATE ($) USACE HIGH ESTIMATE ($) TETRA TECH LOW ESTIMATE ($) TETRA TECH HIGH ESTIMATE ($) EPA REGIONS LOW ESTIMATE ($) EPA REGIONS HIGH ESTIMATE ($) MEAN ($) MEDIAN ($)

115,789 152,780 75,842 251,352 84,853 175,421 130,502 110,378



### The following methods were used to calculate the mean and median total estimated assessment costs for
individual tasks:

• Cos t data for Exhibit B- 1 tasks were provided by sources either as a daily rate or as the cost for an entire investigation. Data provided as a daily rate were converted into the costs for a four

- day investigation, with mean and median values derived from the resulting common dataset.

### B- 12 

### • Per unit mean and median costs for individual tasks were multiplied by the number of units required for completion in the CSM to determine the total cost for each task.

• The mean and median cost of conducting a pre-sampling building survey (see Exhibit B- 5) was derived from daily rates of $1,000 and $1,200 provided by Tetra Tech (up to eight residences) and the USACE (two residences) respectively.

The mean and median total estimated assessment costs do not include costs from Exhibit B -7- Target Identification, as only the USACE provided cost estimates for these tasks.



## Factors Influencing Variability in Cost Estimates

The main sources of variability in site assessment costs result from the wide ranges in cost estimates associated with planning, project management and reporting, along with inc idental costs, as provided by Tetra Tech and EPA Regions. The ranges in values could be influenced by sources including task costs in different categories. Variability could also be the result of comparing cost estimates provided by one source as a daily rate and by another source for an entire investigation, as well as the assumptions used in deciding how to categorize the data received. Specific areas of variability in this cost analysis include the following:

• EPA Regional cost data for field supervision, project management and incidental costs tasks (see Exhibit

B- 1) were obtained from previous investigations and may not realistically compare to the costs associated with this CSM, due to such factors as the scope, size and location of the projects.

• Data provided by EPA Regions did not contain apparent costs for every relevant task in the CSM. For example, the data for previous site investigations received from EPA Region 3 did not include apparent
costs for such Exh ibit B -1 tasks as: project planning, mobilization fees, equipment rental and field supervision. The data from EPA Region 6 for previous investigations provided installation costs for exposed screen monitoring wells, but not sampling costs. Additionally, on e EPA Region 6 cost summary noted that the costs for 12 Summa canister samples were included in Exhibit B-1 tasks. Therefore, there is the potential for missing cost data or the inclusion of unrelated tasks, resulting in underestimates or overestimates, re spectively, in Exhibit B- 1 costs.

• Data received from Tetra Tech included wide cost ranges ($10,000-$80,000 or $10,000-$100,000 each)

for such Exhibit B

- 1 tasks as project planning, project management and reporting. These tasks were noted as being highly va riable depending on the size, scope and location of the site and the staff needed to accomplish the assessment.

• Analytical cost data provided by EPA Region 3 included an assumed unit cost of $600 per sample for Summa canister analysis (see Exhibit B-6). This value was double the next highest value of $300 per sample provided by two other EPA Regions.

• Data validation costs were received from eight EPA Regional offices, with six EPA Regions providing per sample cost information for validation of air sample d ata and water sample data and two EPA Regions providing per sample cost information only for validation of water sample data. Costs provided by EPA Region 1 for validation of water sample data appeared to be an outlier ($202/sample for streamlined QA

revie w and $275/sample for full QA review). The next highest costs were $76/sample (streamlined QA review) and $119/sample (full QA review) for EPA Regions 6 and 9, respectively.

• Discrete target identification costs (see Exhibit B-7) were only provided by the U SACE, while Tetra Tech stated that this task was covered in the pre

- sampling building survey task (see Exhibit B-5).

### B- 13 

## Adjustment of the CSM for use in the Regulatory Impact Analysis

EPA adj usted the CSM in two ways in order to apply the total SI cost estimates to the analysis of t he proposed
rule’s costs:

1. To account for the high degree of variability in the cost estimates provided by different data sources, the analysis excludes several outlier cost values

. 2. To compare the costs of the three regulatory options considered in the RIA, the analysis develops two modified CSMs (in addition to the base case CSM) that include the costs of additional sampli ng, analysis and reporting, as required by each option.

Treatment of Outliers

EPA considered each of the outlier cost values discussed in this document and decided on a case-by- case basis whether to exclude outlier costs from the total cost estimate. Adopting a conservative approach, the analysis excludes only high -cost outliers that are not corroborated by a t least one other data source. Exhibit B

- 9 lists the outlier values that were excluded from the total estimate of the costs of conducting an SI to evaluate SsI threats, together with the range of costs used for each task once outlier values are ignored.

E XHIBIT B

- 9. OUTLIER COST VALUES EXCLUDED FROM TOT AL COST ESTIMATES

TASK DATA SOURCE OUTLIER COST ESTIMATE ($) COST RANGE EXCLUDING OUTLIER VALUE(S) ($)

Planning costs based on previous projects of similar size and scope Tetra Tech (high estimate) 100,000 3,000

- 10,000

Field supervision (e.g., well logging, field

- screening and drilling supervision costs) EPA Region 6 (all estimates) 20,500

- 34,031 2,000

- 8,000

Project management, oversight and reporting costs based on previous projects of similar size and scope Tetra Tech (high estimate) 80,000 8,000

- 17,600

Pre- sampling building survey (labor costs) USACE (single estimate) 19,200 4,000

- 4,800

Laboratory analysis of 76 Summa canister samples using EPA Method TO

- 15 (12 soil gas, 32 sub

- slabs and 32 indoor air quality). EPA Region 3 (single estimate) 45,600 12,540

- 22,800



### After excluding outliers, the analysis uses the median and maximum total cost estimates to represent the costs of conducting an SI for SsI threats in the best

- estimate and high

- end scenarios. These values are presented in Exhibit

B- 10. As with the mean and median total estimated assessment costs presented in Exhibit B -8, the median and
maximum costs in Exhibit B

- 10 do not include costs from Exhibit B-7- Target Identification.

### B- 14 EXHIBIT B

- 10. MEDIAN AND MAXIM UM TOTAL COST ESTIMA TES, EXCLUDING OUTLI ERS

TASK MEDIAN COST ($) MAXIMUM COST ($)

Planning, Staging, Oversight and Reporting 33,179 53,826

Ground Water Characterization 9,000 13,000

Soil Gas Characterization 3,258 4,800

Sub

- slab Vapor Characterization 14,240 21,440

Indoor Air Characterization 11,760 16,160

Laboratory Analysis and Data Validation 24,281 35,290

Total 95,718 144,516



### Alternate CSMs for Regulatory Option Comparison

As described in the body of the report and in Appendix A, the three regulatory options considered for the proposed rulemaking differ in how SsI threats would be scored and—by extension—how investigation of SsI threats would be conducted. In order to compar e the expected cost impacts of each regulatory option, the analysis developed two alternate CSMs in addition to the base case CSM. To develop alternate CSMs, the analysis made the following option -specific modifications:

• Option 1 : Option 1 uses the values from the base case CSM.

• Option 2 : Option 2 modifies the CSM to include 12 additional ground water and 12 additional soil gas samples in order to characterize the extent of the area of subsurface c ontamination . The CSM for Option 2
therefore includes the c osts of installing additional ground water wells ; collecting additional ground water and soil gas samples ; and analysis and validation of the additional water and vapor samples. Because sampling additional ground water and soil gas points is not expected to substantially change the total duration of the SI, the analysis does not change planning, staging, oversight and reporting costs for this option.

• Option 3 : Option 3 uses the modified CSM as Option 2 (i.e., including all costs associated with 12 additional ground water and 12 additional soil gas samples) with one addition. To identify the target population in the potential groundwater migration zone, the CSM for this option includes 64 person-hours of additional analysis and reporting effort.

Incorporating the modifications listed above, the analysis developed alternate median and maximum cost estimates for each of the regulatory options. Exhibit B- 11 presents the median costs by task for the base case CSM and the two alternate CSMs developed for Options 2 and 3. Total median and maximum cost estimates for the three regulatory options are presented in Exhibit B-12.

### B- 15 EXHIBIT B

- 11. MEDIAN COST ESTIMATES BY TASK FOR TH E BASE CASE AND ALTE RNATIVE CSMS

TASK OPTION 1 (BASE CASE) MEDIAN COST ($) OPTION 2 MEDIAN COST ($) OPTION 3 MEDIAN COST ($) Planning, Staging, Oversight and Reporting 33,179 33,179 33,179

Ground Water Characterization 9,000 24,600 24,600

Soil Gas Characterization 3,258 6,516 6,516

Sub

- slab Vapor Characterization 14,240 14,240 14,240

Indoor Air Characterization 11,760 11,760 11,760

Laboratory Analysis and Data Validation 24,281 29,579 29,579

Identifying the Potential Ground Water Migration Zone 0 0 7,040

Total 95,718 119,874 126,914

EXHIBIT B

- 12. TOTAL MEDIAN AND MAXIMUM COST ESTIMAT ES FOR THE THREE REGULA TORY OPTIONS

REGULATORY OPTION MEDIAN COST ($) MAXIMUM COST ($)

Option 1 (Base Case CSM) 95,700 144,516

Option 2 119,874 181,596

Option 3 126,914 189,276

### C-1 

## APPENDIX C: Detailed Methodology for E stimating Impacts on Minority and Low-I ncome Populations

This appendix documents the assessment of demographic data for populations in the vicinity of sites with potential subsurface intrusion ( SsI) contamination. 38 

### The primary objective of the demographic analysis is to determine whether socioeconomically disadvantaged populations (e.g., racial minority and low-income communities) are located preferentially within the vicinity of sites potentially affected by the proposed rule. This analysis provides information related to potential environmental justice concerns regarding the location of potentially affected sites. Because the proposed rule does not require actions that directly affect human health risk, this analysis does not connect popula tion information with potential health risks and is therefore not a full environmental justice analysis.

Methodology

This analysis is based on population statistics from the 2000 Census that indicate the prevalence of potentially disadvantaged populations (e.g.

, racial minorities). The analysis compares “potentially affected populations ” in the vicinity (i.e., within one- mile and three

- mile radii) of sites with potential Ss I contamination to “reference populations” (county-level populations). This comparison indicates whether potentially disadvantaged populations are located preferen tially within the vicinity of Ss I sites. Data sources and analysis methods are
described below.

Potentially Affected and Reference Communities

To represent potentially affected populations, the demographic analysis selected sites from the list of sites potentially affected by the proposed rule . For 47 of the approximately 1,073 sites in this list , latitude and longitude data were obtained from the data sources used to populate the group of sites

. 39 

### The analysis used street address data to determine geographic coordinates for an additional 193 sites, for a total of 240 sites used in the demographic analysis. Sufficient data were not available to det ermine a precise geographic location for the remaining sites in the list

. Exhibit C

- 1 presents the distribution of selected sites across the U.S. Environmental Protection Agency ( EPA ) regions. Though the selected sites come from all ten EPA regions, they are not evenly distributed, with the highest percentage of sites in Regions 6 and 8.

38 The analysis follows methods outlined in “Analysis of Statistics for Pop ulations Residing Near UST Facilities,” Memorandum prepared by RTI International, July 22, 2010.

39 See Chapter 2 of this report for a detailed description of the site sites potentially affected by the proposed rule.

### C-2 EXHIBIT C

- 1. EPA REGIONAL DISTRIBUTIO N OF SITES SELECTED FOR THE DEMOGRAPHIC ANALYSIS

EPA REGION NUMBER OF SITES

ANALYZED PERCENTAGE OF

TOTAL SITES

Region 1 5 2.1%
Region 2 27 11.3%
Region 3 32 13.3%
Region 4 21 8.8%
Region 5 13 5.4%
Region 6 55 22.9%
Region 7 13 5.4%
Region 8 56 23.3%
Region 9 17 7.1%
Region 10 1 0.4%

Total 240 100.0%



### Lacking more conclusive information about the geographic spread of potentially affected sites, the analysis assumes that the geographic coordinates used for each site represent centroids of the site’s extent. In order to ensure that the demographic analysi s considers all communities potentially affected by S sI contamination and remedial actions, the analysis defines “potentially affected populations” in two ways:

1) All people living within a one- mile radius of potentially affected sites, and

2) All people living within a three

- mile radius of potentially affected sites.

These distances were chosen to accommodate the size of potential Superfund sites, which may range from a single facility to a large military installation spanning several square miles. In addition, these radii address the uncertainty related to both the spatial extent of plumes and Ss I pathways, and the uncertainty related to location of
site boundaries.

The analysis uses county

- level populations as references to which the potentially affected popu lations are compared. County- level statistics provide a useful comparative measure of populations at a scale that is larger than the site level but still local enough to allow the analysis to distinguish between local demographic shifts and regional demographic patterns (e.g., higher minority populations in the southeastern U.S.). Exhibit C

- 2 compares the (unweighted) average demographic characteristics of the counties surrounding potentially affected sites to national averages. As the exhibit shows, the se lected counties have, on average, lower concentrations of both minority and low

- income populations, relative to the country as a whole. However, these differences are not statistically significant.

### C-3 EXHIBIT C

- 2. DEMOGRAPHIC CHARA CTERISTICS OF COUNTI ES SURROUNDING SELECTED SITES

DEMOGRAPHIC

CHARACTERISTIC COUNTIES AROUND

SELECTED SITES NATIONAL AVERAGE

Percent Minority Population 28.7% 31.0%
Percent Below Poverty Level 12.3% 13.0%



### Socioeconomic Census Data

The analysis evaluates the following socioeconomic parameters from the 2000 Census for the potentially affected and reference populations:

• Percent minority population (including both percent nonwhite and percent white Hispanic)

• Percent below poverty level (i.e., the percentage of individuals below the Federal poverty line in 1999).

These parameters were selected in order to best address the populations of concern identified in Executive Order 12898 (Environmental Justice). The smallest unit at which these data are available is the Census block group. The analysis retrieved county -level data directly from the 2000 Census county-level results. To obtain demographic data for the potentially affected populations, the analysis employed an ArcGIS aggregation of associated block groups within one- and three

- mile buffers of the selected sites, as described in more detail below.

Data for Potentially Affected Populations

The analysis used ArcGIS software to define one - and three- mile buffers around each selected site and collate
socioeconomic data for th e block groups contained within these buffers. When apportioning 2000 census block group data to the buffers around each site, the analysis employed aerial apportionment to assess the demographic characteristics of populations living near each facility. Un der this approach, if x percent of a block group’s land
area is within the one

- mile (or three

- mile) buffer around a facility, the analysis assumed that x percent of the block group’s population is also within the one

- mile (or three

- mile) buffer. This appro ach relies on the assumption that populations are evenly distributed across block groups, which is a limitation of the analysis. However, in the absence of demographic data at a smaller unit than census block groups, EPA determined that this approach was reasonable.

Results

Exhibits C-3 and C-4 present the results of the unweighted demographic analysis, including the mean and median values for each Census socioeconomic indicator and for each population (i.e. potentially affected and reference populations) as well as the mean and median difference in percentages between populations. Exhibit C -3 presents unweighted results for the one

- mile buffer and Exhibit C -4 presents results for the three -mile buffer. In each exhibit, the difference values result from subtracting the reference community values from the potentially affected community values (so that a positive result indicates a greater percentage in the poten tially affected community). A difference result was produced for each site, thus generating a distribution of 240 difference values. The
exhibits also provide the estimated 95 percent confidence intervals for the mean differences (i.e., b ased on the

### C-4 

### statis tical evaluation, it can be conclude d with 95 percent confidence that the differences in means are between the upper and lower bounds listed in the exhibits).

The results in Exhibits C-3 and C-4 show that the mean differences are relatively small (less tha n four percent in all cases). However, the differences in the means do consistently suggest that the potentially disadvantagedpopulations are present at slightly greater percentages in the vicinity of VI sites, both within the one- and threemile radii. S pecifically, the difference value for percent minority population is roughly four percent higher than the county level within the one-mile buffer and about three percent higher than the county level for the three- mile buffer. The poverty differences are si milarly small positive values: about two percent higher than the county level
for both the one -mile buffer and the three-mile buffer.

Exhibits C-5 and C-6 provide additional statistical results, including standard errors of the mean (SE), a relative
risk ratio (i.e., the mean of potentially affected populations divided by the mean of the reference populations), results of a T test evaluating the statistical significance of the difference in means (i.e., whether the differences in the estimated demographic characteristics are statistically significant). Results for the one

- mile buffer are presented in Exhibit C-5, while Exhibit C-6 has results for the three

- mile buffer. The T test evaluates the null hypothesis that the means between the reference and potentially affected populations are equal. The resulting p

values indicate the probability of observing differences larger than the observed differences under the test assumption that the null hypothesis is true. For the population within the one- mile buffer, th e differences in percent minority population and percent below poverty level with respect to the reference population are significant at the 99 percent certainty level, as indicated by the p values less than 0.01 for both comparisons. This
equates to a pro bability of less than one percent that the results reflect a random distribution. Similarly, for the population within the three- mile buffer, the difference in percent minority population is statistically significant at the 95 percent certainty level (p

- va lue of 0.036) and the difference in percent below poverty level is significant at the 99 percent certainty level (p -value <0.01).

Exhibits C-7, C-8, C-9 and C-10 present results for the population

- weighted statistical analysis. The patterns in
the results are similar to the unweighted results in Exhibits C-3 through C-6. However, the relative magnitudes of the population differences are larger for the weighted analysis results. Comparison of the weighted and unweighted results suggests that sites in higher population areas tend to have more pronounced differences between the local, potentially affected communities and the reference, county

- level communities

.
Exhibit C -11 presents results of an analysis conducted to determine if updated census data (i.e., since the 2000 U.S. Census) would indicate that the proportions of minority and below poverty level populations (weighted)
found in 1 - and 3-mile buffers around the same sites analyzed using 2000 U.S. Census data had decreased. The
results show that the proportion of the minority and below poverty level populations found within the 1- and 3- mile buffers around the same 240 sites analyzed using 2000 U.S. Census data did not decrease . A one- sided two

sample Z -test (testing for decreases only) of the minority and below- poverty -level proportions was performed for each buffer. For all four comparisons, the p-values were greater than 0.99, indicating that the null hypothesis that the perce ntage of minorities and below-poverty-level populations around the 240 sites did not decrease could not be rejected. Therefore, conclusions made based on the 2000 Census data regarding the potentially affected populations could still be applied to the 240 sites. A key limitation of the population- weighted results, however, is the assumption of even distribution of population across census block groups. If populations are distributed unevenly either toward or away from individual sites, then the results of this analysis could change significantly. Additionally, the 2009-2013 A merican Community S urvey data based the population below the poverty level as being based on the household level, while the population-weighted analysis using 2000 U.S. Census data bas ed the below poverty level population on the number of people for which income data was available . As a result, the

### C-5 

### population- weighted results are uncertain and should only be used as a general qualitative indicator that population density may be an impor tant factor in a full analysis of environmental justice impacts.

Conclusion

In summary, this analysis used Census data to compare demographic characteristics for potentially affected populations in the vicinity of vapor intrusion sites versus reference co mmunities (county

- level populations). The differences in the mean percentage socioeconomic results between the potentially affected and the reference communities are relatively small ( less than four percent in all cases) . However, the differences are stati stically significant in all cases, and the results do suggest that potentially disadvantaged populations are located preferentially in the vicinity of sites with pot ential SsI threats.

### C-6 EXHIBIT C -3. SUMMARY RESULTS FOR CENSUS PARAMETERS: 1

- MILE BUFFER (UNWEIGH TED)

CENSUS PARAMETER 1- MILE BUFFER AROUND

FACILITY COUNTY WHERE FACILITY

IS LOCATED DIFFERENCE

MEAN MEDIAN MEAN MEDIAN MEAN MEDIAN 95% CONFIDENCE INTER VAL OF

MEAN DIFFERENCE

LOWER BOUND UPPER BOUND

P ercent Minority Population 32.3 % 25.0 % 28. 7% 2 4.4 % 3.66 % 1.74 % 1.05 % 6.26 %
Percent Below Poverty Level 15.4% 12. 7% 12.3% 1 1.1 % 3.08 % 1.74% 1.86 % 4.31 % Note: Difference summary statistics (mean and median) were calculated from the distribution of difference values (i.e., one result per facility, yielding a distribution of 240 results). Mean values reflect the entire distribution, whereas the median values are based onl y on the 50 th percentile result. For this reason, the mean differ ence results could also be calculated simply by subtracting the reference community mean from the potentially affected community mean (e.g., for mean percent below the poverty line in the one

- mile buffer 15.4 – 12.3 = 3.08). In contrast, the median differe nce values do not necessarily match values derived by subtracting the median values from the underlying distributions. Although the primary results of the analysis are based on mean values, median results are provided for completeness and as an alternative indicator of the distributions’ central tendency.

EXHIBIT C -4 . SUMMARY RESULTS FO R CENSUS PARAMETERS: 3- MILE BUFFER (UNWEIGH TED)

CENSUS PARAMETER 3- MILE BUFFER AROUND

FACILITY COUNTY WHERE FACILITY

IS LOCATED DIFFERENCE

MEAN M EDIAN MEAN MEDIAN MEAN MEDIAN 95% CONFIDENCE INTER VAL OF

MEAN DIFFERENCE

LOWER BOUND UPPER BOUND

PERCENT MINORITY POPULATION 30.8 % 2 5.9 % 28. 7% 2 4.4 % 2.17 % 1.10 % 0.15 % 4.19 %

PERCENT BELOW POVERTY LEVEL 14.2 % 12. 6% 12.3% 1 1.1 % 1.88 % 1.04% 1.04 % 2.72 %

Note: Difference summary statistics (mean and median) were calculated from the distribution of difference values (i.e., one result per facilit y, yielding a distribution of 240 results). Mean values reflect the entire distribution, whereas the median values are based onl y on the 50 th percentile result. For this reason, the mean difference results could also be calculated simply by subtracting the reference community m ean from the potentially affected community mean (e.g., for mean percent below the poverty line in the one

- mi le buffer 14.2 – 12.6 = 1.88). In contrast, the median difference values do not necessarily match values derived by subtracting the median values from the underlying distributions. Although the primary results of the analysis are based on mean values, median results are provided for completeness and as an alternative indicator of the distributions’ central tendency.

### C- 7 EXHIBIT C -5 . STANDARD ERROR, T TEST AND RISK RATIO RESUL TS: 1

- MILE BUFFER (UNWEIGH TED)

CENSUS PARAMETER 1- MILE BUFFER

AROUND SITE COUNTY WHERE

FACILITY IS

LOCATED DIFFERENCE

STANDARD ERROR

OF MEAN STANDARD ERROR

OF MEAN S TANDARD ERROR

OF MEAN T- STATISTIC P- VALUE RATIO SE OF RATIO

PERCENT MINORITY POPULATION 0.0 171 0.0123 0.013 3 2.7 5 0.0064 1.1 3 0.051 2

PERCENT BELOW POVERTY LEVEL 0.0070 0.0035 0.006 3 4.9 3 < 0.0 01 1.2 5 0.0539

EXH IBIT C -6 . STANDARD ERROR, T TEST AND RISK RATIO RESULTS: 3

- MILE BUFFER (UNWEIGH TED)

CENSUS PARAMETER 3- MILE BUFFER

AROUND SITE COUNTY WHERE

FACILITY IS

LOCATED DIFFERENCE

STANDARD ERROR

OF MEAN STANDARD ERROR

OF MEAN S TANDARD ERROR

OF MEAN T- STATISTIC P- VALUE RATIO SE OF RATIO

PERCENT MINORITY POPULATION 0.0151 0.0123 0.0103 2.11 0.036 1.08 0.0399

PERCENT BELOW POVERTY LEVEL 0.0051 0.0035 0.0043 4.38 < 0.0 01 1.15 0.0363

### C-8 EXHIBIT C -7. SUMMARY RESULTS FOR CENSUS PARAMETERS: 1

- MILE BUFFER (WEIGHTE D)

CENSUS PARAMETER 1- MILE BUFFER AROUND

FACILITY COUNTY WHERE FACILITY

IS LOCATED DIFFERENCE

MEAN MEDIAN MEAN MEDIAN MEAN MEDIAN 95% CONFIDENCE INTER VAL OF

MEAN DIFFERENCE

LOWER BOUND UPPER BOUND

PERCENT MINORITY POPULATION 41.1 % 14.8 % 32.9 % 14.9 % 8.23 % 0.332 % 4.13 % 12.3 %

PERCENT BELOW POVERTY LEVEL 16.8 % 8.84 % 11.6 % 7.37 % 5.22 % 0.312% 3.33 % 7.11 %

Notes:
1. Difference summary statistics (mean and median) were calculated from the distribution of difference values (i.e., one result per facility, yielding a distribution of 240 results). Mean values reflect the entire distribution, whereas the median values are based only on the 50 th percentile result. For this reason, the mean differ ence results could also be calculated simply by subtracting the reference community mean from the potentially affected community mean (e.g., for mean percent below the poverty line in the one

- mile buffer 16.8 – 11.6 = 5.22). In contrast, the median differe nce values do not necessarily match values derived by subtracting the median values from the underlying distributions. Althou gh the primary results of the analysis are based on mean values, median results are provided for completeness and as an alternative indicator of the distributions’ central tendency.
2. In the weighted analysis, the county

- level demographic characteristic for the one

- mile buffer comparison are different from the characteristics for the three

- mile buffer comparison because the county

- level characteristics are weighted by the population around the site, which varies by buffer size.

### C-9 EXHIBIT C -8 . SUMMARY RESULTS FO R CENSUS PARAMETERS: 3- MILE BUFFER (WEIGHTE D)

CENSUS PARAMETER 3- MILE BUFFER AROUND

FACILITY COUNTY WHERE FACILITY

IS LOCATED D IFFERENCE

MEAN M EDIAN MEAN MEDIAN MEAN MEDIAN 95% CONFIDENCE INTER VAL OF

MEAN DIFFERENCE

LOWER BOUND UPPER BOUND

PERCENT MINORITY POPULATION 41.8 % 15.7 % 35.9 % 15.3 % 5.90 % 0.186 % 2.74 % 9.06 %

PERCENT BELOW POVERTY LEVEL 14.8 % 7.19 % 11.6 % 7.04 % 3.16 % 0.196% 2.00 % 4.33 %

Notes:
1. Difference summary statistics (mean and median) were calculated from the distribution of difference values (i.e., one result per facility, yielding a distribution of 240 results). Mean values reflect the entire distribution, whereas the median values are based only on the 50 th percentile result. For this reason, the mean difference results could also be calculated simply by subtracting the reference community mean from the potentially affected community mean (e.g ., for mean percent below the poverty line in the one

- mile buffer 14.8 – 11.6 = 3.16). In contrast, the median difference values do not necessarily match values derived by subtracting the median values from the underlying distributions. Although the primar y results of the analysis are based on mean values, median results are provided for completeness and as an alternative indicator of the distributions’ central tendency.
2. In the weighted analysis, the county

- level demographic characteristic for the one

- mile buffer comparison are different from the characteristics for the three

- mile buffer comparison because the county

- level characteristics are weighted by the population around the site, which varies by buffer size.

EXHIBIT C -9 . STANDARD E RROR, T TEST AND RI SK RATIO RESULTS: 1

- MILE BUFFER (WEIGHTE D)

CENSUS PARAMETER 1- MILE BUFFER

AROUND

FACILITY COUNTY WHERE

FACILITY IS

LOCATED DIFFERENCE

STANDARD ERROR

OF MEAN STANDARD ERROR

OF MEAN S TANDARD ERROR

OF MEAN T- STATISTIC P- VALUE RATIO SE OF RATIO

PERCENT MINORITY POPULATION 0.0421 0.0311 0.0209 3.94 <0.001 1.25 0.110

PERCENT BELOW POVERTY LEVEL 0.0146 0.0087 0.0096 5.42 < 0.001 1.45 0.126

### C- 10 EXHIBIT C

- 10 . STANDARD ERROR, T TEST AND RISK RATIO RESULTS: 3

- MILE BUFFER (WEIGHTE D)

CENSUS PARAMETER 3- MILE BUFFER

AROUND

FACILITY COUNTY WHERE

FACILITY IS

LOCATED DIFFERENCE

STANDARD ERROR

OF MEAN STANDARD ERROR

OF MEAN S TANDARD ERROR

OF MEAN T- STATISTIC P- VALUE RATIO SE OF RATIO

PERCENT MINORITY POPULATION 0.0477 0.0381 0.0164 3.60 < 0.001 1.16 0.099

PERCENT BELOW POVERTY LEVEL 0.0131 0.0101 0.0064 4.95 < 0.0 01 1.27 0.101

EXHIBIT C- 11 . DEMOGRAPHIC CHARACTERISTICS OF THE POPULATIONS SURROUNDING SITES POTENTIALLY AF FECTED BY THE PROPOS ED RULE

1- MILE BUFFER AROUND SITES 3- MILE BUFFER AROUND S ITES

MEAN *

(2000 U.S. CENSUS)* MEAN

(2009

- 2013 ACS) DIFFERENCE IN

MEANS MEAN *

(2000 U.S. CENSUS) MEAN

(2009

- 2013 ACS) DIFFERENCE IN

MEANS

Percent Minority Population 41.1% 46.1 %

- 5.0% 41.8 % 47.7 %

- 5.0%
Percent Below Poverty Level 16.8% 18.8 %

- 2.0% 14. 8% 16.4 %

- 5.0%

*WEIGHTED MEANS USED IN THE ANALYSIS USIN G 2000 U.S. CENSUS D ATA

### D- 1 

## APPENDIX D: Costs for Vapor Intrusion Site Inspection Tasks Compiled for Regulatory Impact Analysis

EXHIBIT D

- 1. SUMMARY STATISTIC S FOR VAPOR INTRUSIO N SITE INSPECTION TASK COST S

Task Task Name Units Range ($) Max Value ($) Min Value ($) Mean ($) Median ($) CSM Mean ($) CSM Median

($) CSM Max ($) Min

- No Outliers ($) Mean

- No Outliers ($) Median

- No Outliers ($) Max

- No Outliers ($)

Planning, Staging, Oversight, and Reporting

1 Project Planning Costs

- provided from past investigations (e.g., sampling plan development) Per Investigation 3000 - 10000 100,000 3,000 15,015 4,750 15,015 4,750 100,000 3,000 5,572 4,500 10,000

3 Project Mobilization Fees for Past Investigations (e.g., staging costs) Per Investigation 3000 3,000 1,250 N/A N/A 2,000 2,000 3,000 1,000 2,000 2,000 3,000

8 General Equipment Rental Costs

- provided from past investigations (e.g., peristaltic pump, air pumps, photo ionization detector) Per Investigation 528 - 1055 4,000 400 1,448 879 1,448 879 4,000 400 1,448 879 4,000

10 Field Supervision Costs

- provided from past investigations (e.g., well

- logging, field

screening, well development, sample collection ) Per Investigation 20500 - 35308 35,308 2,000 19,044 20,500 19,044 20,500 35,308 2,000 6,000 8,000 8,000

12 Project Management, Oversight, and Reporting Costs

- provided from past investigations (e.g., project planning, report preparation) Per Investigation 8000 - 17600 80,000 8,000 18,354 12,000 18,354 12,000 80,000 8,000 12,189 12,000 17,600

15 Incidental Costs

- provided from past investigations (e.g., travel, mileage, sample shipping, personal protective equipment (PPE) Per Investigation 3765 - 11226 11,226 100 5,907 5,800 5,907 5,800 11,226 100 5,907 5,800 11,226

Ground Water Well Installation
18 Direct Push Technology

– Exposed Screen Monitoring Well Installation Per Well 608

- 1500 1,500 608 1,084 1,000 6,501 6,000 9,000 3,648 6,501 6,000 9,000 Ground Water Well Sampling
24 Direct Push Technology

- Exposed Screen Monitoring Well Single Sampling Event Per Well 200

- 400 400 200 300 300 1,800 1,800 2,400 1,200 1,800 1,800 2,400
26 Additional Well Sampling Event Per Well 200

- 400 400 200 300 300 1,200 1,200 1,600 1,200 1,200 1,200 1,600 Soil Gas Sampling
30 Direct Push Technology

- soil

- gas sample collection (PRT sampling) Per Sample 155

- 400 400 155 275 272 3,294 3,258 4,800 1,860 3,294 3,258 4,800 Sub

- slab and Crawl Space Vapor Probe Installation
34 Roto

- hammer

- drill

- Installation only of sub

- slab soil

- gas probes Per Probe 105

- 300 300 105 192 175 6,149 5,600 9,600 3,360 6,149 5,600 9,600 Sub

- slab and Crawl Space Sampling
35 Sub

- slab sample collection utilizing Summa canisters Per Sample 101

- 370 370 101 257 270 8,219 8,640 11,840 3,232 8,219 8,640 11,840 Indoor Air Quality Assessment
41 Pre

- sampling Building Survey Daily 1000

- 1200 1,200 1,000 1,100 1,100 4,400 4,400 4,800 4,000 4,400 4,400 4,800
42 Summa canister sampling (assumes batch certification, see comments section) Per Sample 101

- 355 355 101 229 230 7,328 7,360 11,360 3,232 7,328 7,360 11,360 Analytical Costs
47 GC/MS TO

- 15 (i.e. Polar and nonpolar VOCs

– canister) Per Sample 165

- 600 600 165 311 275 23,623 20,900 45,600 12,540 19,228 19,000 22,800
52 GC/MS 8260B Modified (i.e. VOCs

– syringe, bag, vial) Per Sample 85

- 100 100 85 93 93 925 925 1,000 850 925 925 1,000
57 Data Validation (air media) Per Sample 10

- 115 115 10 59 51 4,519 3,876 8,740 760 4,519 3,876 8,740 58 Data Validation (water media) Per Sample 10

- 275 275 10 74.6 48 746 480 2,750 100 746 480 2,750 Target Identification

59 Identify structure composition for each property within the target area (e.g., basement, slab

- on

- grade) Per Investigation 1000 - 15000 15,000 1,000 N/A N/A

60 Identify property use characteristics for each property within the target area (e.g., residence, retail, office, school) Per Investigation 1000 - 5000 5,000 1,000 N/A N/A

61 Quantify the number of human targets per property (e.g., field verify how many people live at each residence and year

- round) Per Investigation 5000 - 15000 15,000 5,000 N/A N/A
Additional Option 2 and 3 SsI Investigative Costs:
18 Direct Push Technology

– Exposed Screen Monitoring Well Installation Per Well 608

- 1500 1,500 608 1,084 1,000 13,003 12,000 18,000 7,296 13,003 12,000 18,000
24 Direct Push Technology

- Exposed Screen Monitoring Well Single Sampling Event Per Well 200

- 400 400 200 300 300 3,600 3,600 4,800 2,400 3,600 3,600 4,800
30 Direct Push Technology

- soil

- gas sample collection (PRT sampling) Per Sample 155

- 400 400 155 275 272 3,294 3,258 4,800 1,860 3,294 3,258 4,800
47 GC/MS TO

- 15 (i.e. Polar and nonpolar VOCs

– canister) Per Sample 165

- 600 600 165 311 275 3,730 3,300 7,200 1,980 3,036 3,000 3,600
52 GC/MS 8260B Modified (i.e. VOCs

– syringe, bag, vial) Per Sample 85

- 100 100 85 93 93 1,110 1,110 1,200 1,020 1,110 1,110 1,200
57 Data Validation (air media) Per Sample 10

- 115 115 10 59 51 714 612 1,380 120 714 612 1,380

58 Data Validation (water media) Per Sample 10 - 275 275 10 75 48 896 576 3,300 120 896 576 3,300

### D-2 Min

- No Mean

- No Median

- Max

- No CSM CSM Outliers ($) Outliers No Outliers ($) Range Max Value Min Value Mean Median CSM Me an Median Max ($) Outliers Task Task Name Units ($) ($) ($) ($) ($) ($) ($) ($) ($)

Option 3 Additional Reporting Costs

66 Identifying the target population in the "Potential Ground Water Migration Zone" Per Investigation 6400

- 7680 7,680 6,400 7,040 7,040 7,040 7,040 7,680 6,400 7,040 7,040 7,680
Total (Option 1) 130,472 110,368 347,024 50,482 97,425 95,718 144,516

Total (Option 2) 156,818 134,824 387,704 65,278 123,077 119,874 181,596

Total (Option 3) 163,858 141,864 395,384 71,678 130,117 126,914 189,276

EXHIBIT D

- 2. EPA REGIONAL/CLP ANALYTICAL AND DATA VALIDATION COSTS

R3 R3 R2 Var. QA Var. QA R4 R4 R5 R1 R1 Unknown Costs Costs Full QA Full QA Unknown R6 R6 R9 R10 Strl. EPA CLP EPA CLP Strl. QA Full QA Level QA Low Est. High Est. Low Est. High Est. Level QA Strl. QA Full QA Strl. QA QA Low Est. High Est. R 5 email Task Task Name Units ($) ($) ($) ($) ($) ($) ($) ($) ($) ($) ($) ($) ($) ($) ($) Analytical Costs GC/MS TO

- 15 (i.e. Polar and nonpolar 47 VOCs

– canister) Per Sample 300
56 OERR/AOC SOW OLC03.2 Per Sample 65 210
57 Data Validation (air media) Per Sample 51 71 87 40 60 48 115 39
58 Data Validation (water media) Per Sample 202 275 19 50 40 60 48 76 115 119 32.84

EXHIBIT D

- 3. COMPREHENSIVE SUM MARY COSTS FOR VAPOR INTRUSION SITE INSPECTION TASKS

R3 Site B R3 TetraTech

Task Task Name Units R6 Site

($) A R6 Site

($) B R6 Site

($) C R6 Site D

($) R3 Site A

($) Summa Canister ($) Site B TAGA

($) R3 Site

($) C USACE Low Est. ($) USACE High Est. ($) TetraTech Low Est. ($) Mid

- range Est. ($) TetraTech High Est. ($) Planning, Staging, Oversight, and Reporting
Per 1 Project Planning Costs

- provided from past investigations (e.g., sampling plan development) Investigation 5,900 4,500 4,245 4,500 3,000 3,000 5,000 10,000 10,000 100,000
Per 3 Project Mobilization Fees for Past Investigations (e.g., staging costs) Investigation 3,000 1,250

8 General Equipment Rental Costs

- provided air pumps, photo ionization detector) from past investigations (e.g., peristaltic pump, Per Investigation 1,055 528 703 4,000 400 2,000

10 Field Supervision Costs

- provided from well development, sample collection ) past investigations (e.g., well

- logging, field

- screening, Per Investigation 20,500 35,308 25,469 34,031 8,000 2,000 8,000

12 Project project Management, Oversight, and Reporting planning, report preparation) Costs

- provided from past investigations (e.g., Per Investigation 17,600 17,060 12,734 10,500 8,000 12,000 12,000 12,000 10,000 10,000 80,000

15 Incidental Costs

- provided from past personal protective equipment (PPE) investigations (e.g., travel, mileage, sample shipping, Per Investigation 3,765 11,226 7,171 5,662 10,975 6,750 5,800 7,525 4,000 100 2,000 Ground Water Well Installation
17 Conventional Monitoring Well Installation Per Well 3,000 1,800 1,950 18 Direct Push Technology

– Exposed Screen Monitoring Well Installation Per Well 608 888 769 1,000 1,500 1,360 1,460 Ground Water Well Sampling

24 Direct Push Technology

- Exposed Screen Monitoring Well Single Sampling Event Per Well 400 200

### D-3 R3 Site B R3 TetraTech

Task Task Name Units R6 Site

($) A R6 Site

($) B R6 Site

($) C R6 Site D

($) R3 Site A

($) Summa Canister ($) Site B TAGA

($) R3 Site

($) C USACE Low Est. ($) USACE High Est. ($) TetraTech Low Est. ($) Mid

- range Est. ($) TetraTech High Est. ($)
26 Additional Well Sampling Event Per Well 400 200 Soil Gas Sampling
30 Direct Push Technology - soil

- gas sample collection (PRT sampling) Per Sample 333 400 155 210 Sub

- slab and Crawl Space Vapor Probe Installation
34 Roto

- hammer

- drill - Installation only of sub

- slab soil

- gas probes Per Probe 250 175 175 200 300 105 140 Sub

- slab and Crawl Space Sampling
35 Sub

- slab sample collection utilizing Summa canisters Per Sample 355 242 101 150 270 310 370 Indoor Air Quality Assessment
41 Pre

- sampling Building Survey Daily 1,200 1,000
42 Summa canister sampling (assumes batch certification, see comments section) Per Sample 355 101 150 310 Analytical Costs
47 GC/MS TO

- 15 (i.e. Polar and nonpolar VOCs – canister) Per Sample 600 250 300 250 165 52 GC/MS 8260B Modified (i.e. VOCs – syringe, bag, vial) Per Sample 100 85
57 Data Validation (air media) Per Sample 100 100 100 100 28 30 10 15 17 58 Data Validation (water media) Per Sample 28 30 10 15 Target Identification

59 Identify structure

on

- grade) composition for each property within the target area (e.g., basement, slab

- Per Investigation 1,000 15,000

60 Identify property use retail, office, school) characteristics for each property within the target area (e.g., residence, Per Investigation 1,000 5,000

61 Quantify the number of human targets each residence and year -round) per property (e.g., field verify how many people live at Per Investigation 5,000 15,000 Additional Option 2 & Option 3 Site Investigation Costs:
18 Direct Push Technology – Exposed Screen Monitoring Well Installation Per Well 608 888 769 1,000 1,500 1,360 1,460
24 Direct Push Technology - Exposed Screen Monitoring Well Single Sampling Event Per Well 400 200
30 Direct Push Technology - soil

- gas sample collection (PRT sampling) Per Sample 333 400 155 210
47 GC/MS TO

- 15 (i.e. Polar and nonpolar VOCs – canister) Per Sample 600 250 300 250 165 52 GC/MS 8260B Modified (i.e. VOCs – syringe, bag, vial) Per Sample 100 85
57 Data Validation (air media) Per Sample 100 100 100 100 28 30 10 15 17
58 Data Validation (water media) Per Sample 28 30 10 15 Option 3 Additional Reporting Costs
Per 66 Identifying the target population in the "Potential Ground Water Migration Zone" Investigation 6,400 7,680 7,680

Notes:

1 N/A refers to a value not calculated due to only one value being provided or insufficient data available to perform a calcula tion.

2 R = EPA Regional Office (e.g., R6 = EPA Region 6)

3 When only one value was provided for an individual task, it was placed in the "low estimate" column.

F inal values utilized provided via Tetra Tech Inc. and US ACE when calculating or adding unit values, therefore the final task values provided may not equal the sum of the 4 individual costs used in their calculation. When realistic, cost information received for multiple groups was combined into larger groupings.

5 The cost data provided for the EPA Region 3 Site B investigation was presented for conducting an investigation with Summa canisters or the TAGA bus.

6 The cost data provided for the EPA Region 3 Site C investigation was assumed to be an investigation conducted in two parts, with the TAGA analysis included in the second trip. Tetra Tech Inc. provided costs for conducting a background indoor air quality sampling event, but as the equipment and labor costs were similar, these costs were not included in 7 the spreadsheet. The only difference was that labor costs were $1,000/day instead of $1,500/da y.

Abbreviations:

1 CSM = conceptual site model

2 PRT = p ost r un t ubing

3 VOCs = volatile organic compounds

### D-4 4 QA = quality assurance

5 EPA CLP = U.S. Environmental Protection Agency Contract Laboratory Program

6 USACE = U.S. Army Corps of Engineers
Assumptions:

1 Analytical methods and costs were often provided separately for ground water, soil gas, vapor intrusion and indoor air media, but with equal costs, therefore information was combined into one grouping.

2 Cost estimates provided by EPA included costs for conducting a separate background indoor air quality sampling event. It was assumed that costs for conducting a background indoor air quality sampling event would be similar to the costs listed in tasks 41

- 46, therefore no separate br eakout costs were provided.

3 Summa canister preparation costs were noted when provided, otherwise they were assumed to be included in other provided costs (e.g., analytical costs).

4 EPA Regional cost estimates providing Field Sampling and Analysis costs for Summa canisters and labor were handled by assuming the Summa canister unit costs were the analytical costs, while the sampling unit costs were derived by dividing the labor costs by the overall number of samples col lected.

5 Unless specified otherwise, analytical method used for indoor air, soil gas and sub

- slab samples was assumed to be TO

- 15.

6 The same analytical methods and costs were often provided separately for ground water, soil gas, vapor intrusion, and indoor air media, as the costs were the same, so information was combined into one grouping.