Framework for Identifying and

Evaluating Lead‐Based Paint Hazards

from Renovation, Repair, and Painting

Activities in Public and Commercial

Buildings

  

   May 2014

  

EPA Office of Pollution Prevention and Toxics

1200 Pennsylvania Avenue, N.W.

Washington, DC 20460

  

    
US EPA ii May 2014

Contents

1. Introduction .................................................................................................................................. 2

2. Background ................................................................................................................................... 3

2.1. Previous Approach for Residences and COFs............................................................................... 3

2.1.1. Identifying Hazards.......................................................................................................... 3

2.1.2. Evaluating Hazards .......................................................................................................... 3

2.2. Considerations for an Approach for P&CBs.................................................................................. 3

3. Discussion of a Potential P&CB Approach ...................................................................................... 4

3.1. Hazard Identification .................................................................................................................... 5

3.2. Hazard Evaluation......................................................................................................................... 6

3.3. Hazard Evaluation With Monte Carlo Analyses............................................................................ 7

3.4. Hazard Evaluation Using Child’s IQ Decrements..........................................................................7

3.5. Considerations for Using a Scenario‐Specific Approach...............................................................9

3.5.1. Applicability/generalizability of Modeled Scenarios.......................................................9

3.5.2. Selection of Risk Reduction Measures............................................................................. 9

3.5.3. Exposure at Residences and COFs................................................................................... 9

4. References................................................................................................................................... 10

Appendix A. Exposure and Risk Characterization...............................................................................A‐1

References........................................................................................................................................A‐6

Appendix B. Variables Being Considered for Use in the Analysis and Designation of

Scenario or Monte Carlo Variables in the Model Framework ......................................................A‐7

Appendix C. Preliminary Analysis....................................................................................................A‐10

Figures

Figure 1. Evaluation of Hazard across Monte Carlo Percentiles and Scenario Means................................. 8

Figure 2. Schematic of EPA’s Exposure and Risk Assessment Process.......................................................A‐1

Figure 3. Modeling Framework for Exterior Renovation Activities ...........................................................A‐4

Figure 4. Modeling Framework for Interior Renovation Activities............................................................A‐5

Figure 5. Trends in Incremental IQ Change & Time Spent for Children Inside P&CBs

(Preliminary Analyses)............................................................................................................A‐11

Figure 6. Trends in Incremental IQ Change & Room Size for Children Inside P&CBs

(Preliminary Analyses)............................................................................................................A‐11
Framework for Identifying and Evaluating Lead‐Based Paint Hazards from Renovation, Repair, and Painting

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Acronyms and Abbreviations

Acronym / Abbreviation Stands For

AERMOD American Meteorological Society (AMS) and the U.S. Environmental Protection

Agency (EPA) Regulatory Model Improvement Committee (AERMIC) Model

COFs Child‐Occupied Facilities

EPA U.S. Environmental Protection Agency

IQ Intelligence Quotient

OSHA U.S. Occupational Safety and Health Administration

P&CBs Public and Commercial Buildings  

PbB Blood Lead

RRP Renovation, Repair, and Painting

SAB Science Advisory Board

TSCA Toxic Substances Control Act
Framework for Identifying and Evaluating Lead‐Based Paint Hazards from Renovation, Repair, and Painting

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1. Introduction

The U.S. Environmental Protection Agency (EPA) is currently in the process of determining whether or

not lead‐based paint hazards are created by renovation, repair and painting (RRP) activities in public and

commercial buildings (P&CBs), as required under section 402(c)(3) of the Toxic Substances Control Act

(TSCA). For those renovation activities in P&CBs that create lead‐based paint hazards, TSCA directs EPA

to address the hazards through regulation.  

This document will explain, in general terms, how EPA could define what constitutes a “lead‐based paint

hazard” for P&CBs undergoing renovations. EPA refers to this as “hazard identification”, pursuant to

TSCA section 4031

. This document also discusses how EPA could assess the expected impact of

renovation activities in P&CBs in order to determine whether or not RRP activities would be expected to

create a hazard. EPA refers to this as “hazard evaluation”, pursuant to TSCA section 402(c)(3)2

. If the

analysis indicates that hazards are created, EPA is directed by TSCA section 402(c)(3) to propose

appropriate regulatory controls to reduce or prevent exposure.  

In two separate rulemakings, EPA has previously defined lead‐based paint hazards in residences and

child‐occupied facilities (COFs), and evaluated whether such hazards would result from RRP activities of

those buildings. For P&CBs, EPA is considering an approach that is different from our previous

residential and COF approach, both in the timing and the sequence of events, as well as in the manner in

which the Agency defines and evaluates hazards. EPA previously took a uniform approach to identifying

and evaluating hazards under TSCA for residences and COFs. This document describes a more tailored

approach that could be used for P&CBs. In addition, for P&CBs EPA would combine the identification of

hazards, the evaluation of whether hazards occur and any proposed regulatory requirements, if

appropriate, in one proposed rule. Because of these differences, EPA is providing an early opportunity,

prior to any proposal, for interested parties to review, consider, and provide feedback on the approach

described herein.

Because EPA is providing this information and opportunity for public comment prior to issuing any

proposed rule, the information contained in this document is limited and does not represent or

constitute an Agency decision or regulatory proposal. Additionally, this document does not provide

significant detail regarding modeling inputs and results, how EPA might apply the results of any analyses,

or a discussion regarding what magnitude of deleterious health effect would be considered to be

adverse. Further details and the results of such analyses would be provided for review and comment in

any future proposal. In addition, EPA plans to make public, and provide for peer review of any such

analyses.

                                                            

1 15 U.S. Code § 2683 2

 15 U.S.C. § 2682(c)(3). 
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2. Background

2.1. Previous Approach for Residences and COFs

2.1.1. Identifying Hazards

For residences and COFs, EPA promulgated a uniform standard under TSCA 403 defining a level of lead in

various media (i.e., dust, soil, paint, etc.) that EPA would consider to be dangerous, as a persistent

condition, based on available scientific literature about the health effects of lead to adults and children

and expected exposure in residences and COFs. In 2001, EPA promulgated a regulation that identified,

for residential dwellings and COFs, three different types of lead‐based paint hazards: paint‐lead hazards,

dust‐lead hazards, and soil‐lead hazards (EPA 2001). EPA relied on the Centers for Disease Control (CDC)

“level of concern” at the time3

, as well as other information as described in the preamble to that (403)

rule, to inform our decision about what health endpoint and magnitude would be considered an adverse

health effect. At the time, the CDC level of concern was defined as a blood lead level for children greater

than or equal to 10 μg/dL (CDC, 1991). The EPA residential and COF hazard standards were developed to

provide a relatively low chance that an individual child would experience a blood lead level at or above

10 μg/dL.

2.1.2. Evaluating Hazards

TSCA section 402(c)(3) requires EPA to evaluate whether or not renovation activities create lead‐based

paint hazards. For residences and COFs, the hazard finding was made by first determining the dust‐lead

levels that would be generated by renovation activities and then comparing these levels to the hazard

standard. This approach was used for the 2008 RRP Rule (US EPA, 2008), wherein EPA compared the

observed dust‐lead levels from the renovations tested in the Dust Study (US EPA, 2007) to the dust‐lead

hazard standard promulgated in 2001 (i.e., 40 μg/ft2 on floors or 250 μg/ft2 on interior window sills). Any

renovation activities that created dust‐lead levels that exceeded the dust‐lead hazard standard for floors

were considered to create hazards. This approach formed the basis for EPA’s determination that all

renovation activities that disturb paint in target housing and COFs create lead‐based paint hazards.

2.2. Considerations for an Approach for P&CBs  

The 2001 hazard standards apply only to target housing and COFs. EPA has explored setting hazard

standard(s) for P&CBs. Attempting to identify and apply a “one size fits all” numerical dust‐lead level or

                                                            

3 Since EPA promulgated the hazard standards in 2001, CDC has updated its recommendations on children’s blood lead levels.

Experts now use a reference level of 5 micrograms per deciliter to identify children with blood lead levels that are much

higher than most children’s levels. This new level is based on the U.S. population of children ages 1‐5 years who are in the

highest 2.5% of children when tested for lead in their blood.
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other media metric, however, may not be appropriate for P&CBs. Exposure times in P&CBs are much

more varied than those in homes and COFs. Children and adults may spend only a few minutes in certain

P&CBs, while other exposure may last much longer, such as in a school or similar facility for children 6

years and older, and workplaces for adults. P&CBs where children under 6 years spend significant

amounts of time are already regulated under the 2008 RRP rule. The tailored approach described in this

Framework avoids the creation of a uniform hazard standard that may be more protective than

necessary in some cases and not protective enough in others.

In addition, P&CBs vary greatly in terms of their size, shape, and room configurations, compared to

residences and COFs. EPA hopes to take this broad variability into account and is therefore considering

an approach to more appropriately account for risk. The approach described in this document, referred

to as the “scenario‐specific approach”, is designed to account for the variable amounts of time spent in

P&CBs, the broad heterogeneity in building sizes and configurations, and the short‐term nature of the

exposure resulting from renovation activities in order to assess risk.

If selected, the scenario‐specific approach described in this document would be used to make a hazard

finding inside P&CBs resulting from renovations of the same, or nearby P&CBs. This approach would be

used to support a hazard finding for these situations inside P&CBs where existing hazard standards do

not exist. As described here, the analytical approach and analysis plan would not address hazards to

passers‐by or individuals that could be exposed to lead outside of P&CBs through air, soil, or other

media, or for exposure at homes and COFs where hazard standards are already established.  

3. Discussion of a Potential P&CB Approach

Using the tailored approach, EPA would model exposure to lead from renovations in a wide distribution

of building types, resulting from various renovation activities and taking into consideration the different

age groups of occupants and the varied exposure times that might occur. This distribution of activities

would allow EPA to characterize risk across all the exposure conditions and situations that may occur.

Once this probabilistic distribution is developed EPA would review the modeling results including

estimates of blood lead changes and appropriate health endpoints, such as IQ decrements for young

children. To inform the hazard finding, EPA would consider the magnitude of any predicted deleterious

health effects as well as how frequently that exposure situation is likely to occur. This approach allows

EPA the ability to take into account the varied exposure times for individuals, and the variability in

buildings and renovations when characterizing risks. This tailored approach would provide the ability to

apply any regulatory requirements to only those situations that most closely resemble those modeled

scenarios in which the probabilistic modeling predicted that an adverse health effect would occur. This

allows EPA the ability to limit the scope of any regulatory intervention in a way not possible when

relying on a uniform hazard standard.   

The adaptability and tailored nature of the scenario‐specific approach is evident when reviewing the

results of the preliminary analysis shown in Appendix C. However, preliminary analysis results are not
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representative of all scenarios that could be analyzed, and the modeling inputs and parameters have not

been finalized. Therefore, the preliminary findings reported in Appendix C should not be construed as

final and may change pending subsequent and more comprehensive analyses. The preliminary analysis

trends displayed in Figure 5 of Appendix C, indicate that, where other factors such as room size are held

equal, renovations in buildings where children spend longer amounts of time result in considerably

larger deleterious health effects (Incremental IQ change) than do renovations in buildings where

children spend shorter amounts of time. As another example, reflected in Figure 6 of Appendix C, the

preliminary analysis indicates that, where other factors such as time of exposure are held equal,

renovations that take place when children are in the renovation workspace and renovations in smaller

rooms result in larger adverse health effects (Incremental IQ change). The advantage of using this

approach is that it is possible for EPA, by modeling exposures specific to different scenarios, to avoid

reliance on a uniform hazard standard that may be more protective than necessary in some cases and

not protective enough in others. As a result, EPA expects that the scenario specific approach would

enable the Agency to evaluate risk and target the application of any potential regulatory requirements

to situations in a more efficient and appropriate manner. In addition, EPA would be able to more

accurately ascertain if there are renovation situations in which regulatory intervention is necessary

because the risk to building occupants or visitors is particularly significant.

3.1. Hazard Identification

The scenario‐specific approach would define lead‐based paint hazards inside P&CBs in terms of

exposures created by P&CB renovation conditions that result in adverse health effects.  

TSCA Section 401(10) defines a “lead‐based paint hazard” as:

any condition that causes exposure to lead from lead‐contaminated dust, lead‐

contaminated soil, lead‐contaminated paint that is deteriorated or present in accessible

surfaces, friction surfaces, or impact surfaces that would result in adverse human health

effects established by the Administrator under this title.4,5

  

Under this approach, EPA would consider the health implications of lead exposure and define lead‐

based paint hazards – solely for the purposes of evaluating exposures from renovations in P&CBs – as

any condition that causes exposure to lead‐based paint dust that would result in health effects that the

Agency finds to be adverse. The determination of whether or not a health effect is adverse would be

                                                            

4 15 U.S.C. § 2681(10) (stating that EPA must classify as a lead-based paint hazard, “any condition that causes exposure to lead 

from lead contaminated dust, lead-contaminated soil, lead contaminated paint that is deteriorated or present in accessible 

surfaces, friction surfaces, or impact surfaces that would result in adverse human health effects” as established by EPA).

5 The definition in section 401 encompasses both exposure and effects, which by definition are components of a risk assessment. 
Framework for Identifying and Evaluating Lead‐Based Paint Hazards from Renovation, Repair, and Painting

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informed by a variety of considerations including available scientific literature, measurability, frequency

of occurrence, biological significance, etc.  

EPA is currently evaluating the literature and the conclusions included in both the Integrated Science

Assessment for Lead (US EPA, 2013) and the National Toxicology Program Monograph on Health Effects

of Low‐Level Lead (NTP, 2012) to develop the concentration‐response functions for the health effects,

such as renal and cardiovascular, associated with lead exposure for both older children and adults. As

appropriate, those concentration‐response functions and the magnitude of associated health effects

resulting from incremental changes in blood lead level from the modeled renovation scenarios would

form the basis for EPA’s identification of hazard. For children, intelligence quotient (IQ) change and

possibly other endpoints would be evaluated as a quantifiable health effect. However, EPA notes that

most P&CBs where children under 6 years would spend longer amounts of time are already regulated

under the 2008 RRP rule as COFs6

.  

For example, EPA might find that a particular IQ decrement in young children is an adverse health effect.

A hazard, then, would be identified as any renovation condition that causes exposure to lead‐based

paint dust that would result in that particular IQ decrement for children. A similar identification could be

made for adults based on other health endpoints as well.

3.2. Hazard Evaluation

Under this approach, EPA would evaluate whether or not exposure to leaded dust from specific

renovation scenarios in P&CBs would result in the health effects identified as adverse. For those that do,

EPA would determine that lead‐based paint hazards are created. To perform this analysis, EPA would

assess elevations in lead exposure resulting from a broad range of scenarios, considering variations in

types of renovation activities, building types, sizes and configurations, use and occupancy patterns,

cleaning frequencies, etc., which are designed to be reflective of actual P&CB settings. EPA could

evaluate those exposures to both children and adults and consider the implications on blood lead levels

and health effects. For those scenarios where our modeling predicts that the magnitude of health effect

change due to the renovation activity is significant enough to be considered adverse, EPA would make

the finding that lead‐based paint hazards are created. EPA would consider how to generalize the results

of the analysis and craft any regulatory requirements to apply only to those renovation activities and

P&CB categories where exposure is reflective of the modeled scenarios in which a hazard was found.

                                                            

6 40 C.F.R. 745.80 Child-occupied facility means a building, or portion of a building, constructed prior to 1978, visited regularly 

by the same child, under 6 years of age, on at least two different days within any week (Sunday through Saturday period), 

provided that each day's visit lasts at least 3 hours and the combined weekly visits last at least 6 hours, and the combined annual 

visits last at least 60 hours. 
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3.3. Hazard Evaluation With Monte Carlo Analyses

EPA would utilize a Monte Carlo method to evaluate hazards inside P&CBs if using a scenario‐specific

approach. The Monte Carlo analysis is described in Appendix A.2 and the variables under consideration

are described in Appendix B. The Monte Carlo analysis would repeatedly sample from distributions of

these variables to create a probabilistic distribution of exposure for each renovation scenario. EPA

would then consider these single scenario exposures within the overall context of the general

population. To do so, the variability within each exposure scenario and the probability of occurrence for

each exposure scenario would be estimated.   

For children, EPA would estimate the resultant IQ level changes due to lead exposure from both RRP

activities and background sources (from non‐renovation activities), and then subtract out the IQ change

related to background alone. The magnitude of the incremental IQ change may be affected by

background levels, since the background level affects the shape of the concentration‐response curve.

However, in evaluating distributions of results for the scenario‐specific approach, only the renovation‐

related (incremental) exposures and effects would be considered in making a hazard finding. For IQ

change in children, or for any other health effect chosen for the analysis, the concentration‐response

function can be used to create a distribution of incremental health effect changes.

The task of identifying adverse adult health effects for exposure scenarios anticipated to occur during

renovation of P&CBs presents some unique difficulties. The median blood lead level in the general US

population, based on the latest NHANES data, is now approximately 1 μg/dL, and the 95th percentile is

3.5 μg/dL (CDC, 2013). However, the literature on health effects at this exposure level is sparse,

especially for adult health endpoints. It is expected that renovation exposure scenarios in P&CBs would

result in a short‐term increase in exposures while the renovation is underway, and then the exposures

will quickly decline after the work is completed. The contribution of short‐term exposures to total blood

or bone lead concentration can be modeled, but the overall impact of the changes to total blood and

bone lead from P&CB renovation scenarios is expected to be quite small.    

3.4. Hazard Evaluation Using Child’s IQ Decrements

EPA would use Monte Carlo predictions of incremental IQ decrements for children to evaluate hazards

to children and make the hazard finding for exposure inside P&CBs from interior and exterior

renovations. Many scenarios could return small mean IQ changes related to the renovation. Relatively

larger IQ changes, however, may occur in two different situations. In the first case, consider a scenario

resulting in a small mean IQ change (Figure 1A). The Monte Carlo simulation provides an estimate of the

distribution of IQ changes for that scenario, and the mean might be the point shown with the “X” in the

figure. When examined based on percentiles, however, the higher percentiles could represent a lead

hazard (the red portion of curve within the “Hazard” shaded area). Thus, the mean exposures can be

low, but a certain fraction of the population in that exposure scenario is expected to have IQ changes

that result in a hazard. In the second case, consider the mean IQ changes across all the different
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US EPA 8 May 2014

scenarios (Figure 1B). Most of the mean IQ changes (the blue bars) may not result in a hazard. The IQ

changes from some fraction of those scenarios, however, could result in a lead hazard (the red bars that

reach the “Hazard” shaded area).  

To analyze potential hazards, EPA would examine the various distributions across percentiles in a single

scenario (Figure 1A) and across different scenarios (Figure 1B). The collection of these distributions helps

account for the total variability in exposure owing to environmental, lifestyle, and biokinetic differences

across the population. EPA would place the less frequent, high incremental IQ changes within the

context of expected (mean) incremental IQ changes. Because each scenario is not equally likely, EPA

would provide a discussion of the relative frequency of these high incremental IQ changes. The hazard

finding would be made based on an overall judgment of the frequency and magnitude of incremental

health effect changes resulting from P&CB renovations.

Figure 1. Evaluation of Hazard across Monte Carlo Percentiles and Scenario Means

Hazard

5th 50th 95th

Hazard

Scenario

1

Scenario

10,000

Scenario

15,000

A. One Scenario, 20,000

Monte Carlo Iterations

B. 15,000 Scenarios, Mean

Across Monte Carlo

Iterations

Percentiles Scenarios

Incremental IQ Loss Incremental IQ Loss X
Framework for Identifying and Evaluating Lead‐Based Paint Hazards from Renovation, Repair, and Painting

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US EPA 9 May 2014

3.5. Considerations for Using a Scenario‐Specific Approach

3.5.1. Applicability/generalizability of Modeled Scenarios

The scenario‐specific approach seeks to more accurately address hazards and minimize regulatory

burden. However, if appropriate, EPA must also be able to use the approach to propose and implement

regulatory requirements that can be understood and adopted by the regulated community. It is possible

that the analysis could indicate hazards in scenarios that are unlikely to occur, or occur in only very

limited instances affecting a small number of people. EPA would consider how to generalize the hazard

findings from the scenario‐specific analysis to assess the effects of a potential regulation on the

population (and on sensitive sub‐populations) in considering regulatory options.   

3.5.2. Selection of Risk Reduction Measures

The exposure modeling construct of the scenario‐specific approach allows a more targeted way for EPA

to evaluate the effect of a variety of mitigation measures in reducing exposures that occur inside P&CBs.

For example, this approach can examine the effectiveness of potential regulatory requirements, such as

preventing occupants of P&CBs from being present in the workspace during the renovation, the use of

plastic barriers, prohibiting certain work practices and requiring the use of HEPA dust capture systems

on equipment, and cleaning requirements to contain or otherwise limit exposure to leaded dust. This is

accomplished by including separate model simulations implementing each work practice option and

estimating the resulting difference in incremental blood lead levels or health effect changes with and

without the various regulatory options.

3.5.3. Exposure at Residences and COFs

The lead dust created during P&CB renovations can move downwind to surrounding COFs, residences

and P&CBs. This dust can penetrate these buildings via air infiltration. In addition, dust can deposit on

the ground or hard surfaces, leading to elevated lead levels and subsequent track‐in of dust which would

contribute to interior dust levels. These elevated media concentrations may impact the children and/or

adults within these nearby buildings. EPA is considering how to evaluate hazards created in nearby

residences and COFs as a result of exterior renovations of P&CBs. Because, as discussed earlier, there is

an existing hazard standard that applies to residences and COFs, EPA could evaluate whether hazards

are created inside nearby residences and COFs by comparing estimated dust lead levels to the existing

residential and COF hazard standard of 40 μg/ft2 for floors, and 250 μg/ft2 for interior window sills.  

    
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4. References  

Centers for Disease Control and Prevention, (1991). Preventing Lead Poisoning in Young Children.                               

Atlanta, GA: CDC.

Centers for Disease Control and Prevention, (2013).  Fourth Report on Human Exposure to

Environmental Chemicals, Updated Tables, (September, 2013). Atlanta, GA: U.S. Department of

Health and Human Services, Centers for Disease Control and Prevention.

http://www.cdc.gov/exposurereport/

Lanphear B; Hornung R; Khoury J; Yolton K; Baghurst P; Bellinger D; Canfield R; Dietrich K; Bornschein R;

Greene T; Rothenberg S; Needleman H; Schnaas L; Wasserman G; Graziano J; Roberts R. (2005).

Low‐level environmental lead exposure and children's intellectual function: an international

pooled analysis. Environmental Health Perspectives 113:894–899.

National Toxicology Program. (2012). National Toxicology Program Monograph on Health Effects of Low‐

Level Lead. Available at http://ntp.niehs.nih.gov/?objectid=4F04B8EA‐B187‐9EF2‐

9F9413C68E76458E.

OSHA. (2004) Safety and Health Regulations for Construction, Occupational Health and Environmental

Controls: Lead.  29 CFR – 1926.62.

https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=106

41.

US EPA. (1998). Risk Analysis to Support Standards for Lead in Paint, Dust, and Soil. Appendix G: Health

effects associated with exposure to lead and internal lead doses in humans. EPA 747‐R‐97‐006.

Washington, DC: US Environmental Protection Agency, Office of Pollution Prevention and Toxics.

Available online at: http://www.epa.gov/lead/pubs/toc.pdf.  

US EPA. (2001). Lead; Identification of Dangerous Levels of Lead; Final Rule.  Federal Register Volume 66,

Number 4 (Friday, January 5, 2001) [Pages 1206‐1240], http://www.epa.gov/fedrgstr/EPA‐

TOX/2001/January/Day‐05/t84.pdf

US EPA. (2007). Draft Final Report on Characterization of Dust Lead Levels After Renovation, Repair, and

Painting Activities. Prepared for EPA’s Office of Pollution Prevention and Toxics (OPPT). Available

online at: http://www.epa.gov/lead/pubs/duststudy01‐23‐07.pdf  

US EPA. (2008) Lead; Renovation, Repair, and Painting Program; Final Rule.  Federal Register Volume 73,

Number 78 (Tuesday, April 22, 2008)[Pages 21692‐21769] Docket number: EPA‐HQ‐OPPT‐2005‐

0049; FRL‐8355‐7, http://www.gpo.gov/fdsys/pkg/FR‐2008‐04‐22/html/E8‐8141.htm.

US EPA. (2010a). Advanced Notice of Proposed Rulemaking for Public and Commercial Buildings. Docket

number: EPA‐HQ‐OPPT‐2010‐0173. http://www.gpo.gov/fdsys/pkg/FR‐2010‐05‐06/html/2010‐

10097.htm.

US EPA. (2013). Integrated Science Assessment for Lead. U.S. Environmental Protection Agency,

Washington, DC, EPA/600/R‐10/075F.
Appendix A. Exposure and Risk Characterization

A.1. Exposure Assessment Process

The left‐hand portion of Figure 2 shows the exposure assessment process, as described in EPA’s

Guidelines for Exposure Assessment (US EPA, 1992). Each numbered box represents a separate step in

the assessment, from planning, to finding models and input values, to estimating media concentrations

and dose, to characterizing uncertainty. The right‐hand portion of the figure incorporates the analysis of

health effects and characterization of risk as described in EPA’s Framework for Human Health Risk

Assessment to Inform Decision Making (US EPA, 2014). The Framework takes into account

recommendations on risk assessment processes described in the National Research Council’s (NRC) 2009

report, Science and Decisions: Advancing Risk Assessment (NRC, 2009) to use a risk‐based approach to

establish whether a hazard exists from renovations of P&CBs with lead‐based paint. The figure indicates

how health effects and concentration‐response relationships are developed so that the exposure

assessment metrics (intake or dose) can be linked to specific health effects.  

Figure 2. Schematic of EPA’s Exposure and Risk Assessment Process
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A.2. Risk Characterization Inside P&CBs

This section describes how EPA would assess the hazard, exposure, and risk to the U.S. population inside

P&CBs from the renovation, repair, and painting of P&CBs using the scenario‐specific approach7

. Lead

dust can persist in the room being renovated or migrate to nearby rooms, even after the renovation is

complete. The level of exposure to children and adults will depend on, among other things, the extent to

which they spend time in the renovation room or an adjacent room, either during or after the

renovation (or both), and the amount of time they spend in the building.

Potential P&CB exposures can be characterized by estimating the media concentrations (soil and dust)

for each renovation situation and combining these concentrations with age‐dependent and building

specific activity patterns to estimate the resulting blood lead levels. Finally, these levels may be linked to

appropriate, measureable, and quantifiable health effects via concentration‐response functions, derived

from empirical studies (if available and appropriate for the analysis). Incremental blood lead level

changes and health effect changes resulting from the renovation will be developed by subtracting the

estimated blood lead level due to background exposure from the full renovation model simulation.  

Each individual has some exposure to lead via sources other than renovation activities, and this

background exposure will vary across the population. The specific health effects, such as incremental IQ

change in children, can be estimated by comparing the expected background effect to the expected

post‐renovation effect via appropriate concentration‐response functions. The change in IQ for each unit

change in blood lead (PbB) level is proportionately larger for children with lower background exposures.

Thus, background exposure is an important piece in estimating any lead‐related health effect.  

Variability would be accounted for by performing a probabilistic Monte Carlo analysis as part of the

overall exposure analysis framework (see Appendix A). First, EPA would determine a set of scenario

variables and representative ranges of values for these variables, to which the exposure estimates are

highly sensitive. EPA would also determine a range of values for each scenario variable (see Appendix B).

EPA performed some preliminary analyses to determine the impact of different variables on incremental

IQ and PbB level changes for children. This analysis helped identify variables that require

characterization using distributions (higher impact variables) versus variables that can be parameterized

using a single point estimate. Additional information is provided in Appendix C.

To perform the Monte Carlo analysis, each scenario would be run 20,000 times (where each run is

referred to as an “iteration”). Preliminary testing indicates that 20,000 iterations would be appropriate

in order to optimize the combination of accuracy and run‐time efficiency. Each different scenario would

be defined by a specific combination of values for the scenario variables listed in Appendix B. For each of

the 20,000 iterations within each scenario, a value would be selected randomly for every Monte Carlo

variable from its associated distribution. After all iterations are completed, the exposure estimates

would be averaged to estimate a mean value, and other summary statistics, for that exposure scenario.  

                                                            

7 For information on how EPA has previously assessed hazards using the hazard standard approach please refer to the preamble

to the 2008 final Renovation, Repair, and Painting Rule (US EPA, 2008).
Framework for Identifying and Evaluating Lead‐Based Paint Hazards from Renovation, Repair, and Painting

Activities in Public and Commercial Buildings

US EPA A‐3 May 2014

Note that each model iteration is essentially a hypothetical but demographically representative

individual’s exposure within that scenario. The distribution of characteristics of these 20,000

hypothetical individuals per scenario will, by design, mimic the expected distributions of those

characteristics in the US population. After all 20,000 hypothetical individuals have been generated and

evaluated (for expected background blood lead levels and for expected post‐renovation blood lead

levels), the mean and other summary statistics for these blood lead levels (or for their health effect

endpoints, via concentration‐response functions) will be calculated. At this point these summary

statistics are describing the distribution of the population‐level response to the particular exposure

scenario.

To estimate the total population exposure, EPA would determine the probability of occurrence of each

exposure scenario based on both population and building survey data. The final population exposure

estimate represents the population‐wide estimate of exposure to lead due to P&CB renovations. EPA

would use the distributions from the Monte Carlo analysis among the various scenarios to evaluate

whether a hazard exists inside P&CBs.

EPA would conduct sensitivity analyses to determine the influence of each variable on the model

outputs. Uncertainties associated with many variables would also be documented and described in the

analysis.

A.3. Models Being Considered for Use in the Full Analysis

EPA has three specific goals for the models expected to be used in the analysis:

1. To use peer‐reviewed models wherever possible,

2. To avoid models that require more inputs than can be realistically determined using existing data,

and

3. To remain consistent with the 2008 RRP analysis while updating any models that have been

improved since then.

For the exterior analysis (Figure 3), EPA will likely use the AERMOD (US EPA, 2009) modeling system to

model the dispersion of the lead‐containing dust downwind of the renovated building. AERMOD is an

EPA‐recommended (http://www.epa.gov/scram001/dispersion_prefrec.htm) Gaussian dispersion model

that incorporates meteorological and land‐use characteristics, and adjustments for obstructions.

To estimate the indoor dust lead loadings resulting from the airborne renovation‐derived lead at nearby

receptors (Figure 4), a mass‐balance indoor dust model that the Science Advisory Board (SAB) originally

reviewed in 2010 (US EPA, 2010b) is likely to be used. The model incorporates air exchange between the

indoor and outdoor environments, indoor deposition, indoor re‐suspension, cleaning frequency and

efficiency, and track‐in of dust from outdoor soil.  

A Monte Carlo model can be developed using the Python programming language. The model would

consist of several modules that perform lookups, sampling, and calculations based on input files

specifying the distributions of parameter values, such as the AERMOD air concentration files, indoor

dust lead and outdoor soil lead concentration files, and the Leggett response surface tables. Each lookup
Framework for Identifying and Evaluating Lead‐Based Paint Hazards from Renovation, Repair, and Painting

Activities in Public and Commercial Buildings

US EPA A‐4 May 2014

and calculation step would be designed as a separate function in the code. These modules would

provide the overall model with data about how environmental concentrations vary over time, and how

hypothetical individuals of different ages come into contact with these environmental concentrations

based on age‐driven activity patterns and exposure factors. After verifying the calculations being

performed, test cases would be run in the model, and trends across model scenarios would be

examined, for the purposes of further quality assurance, to ensure the trends and magnitudes of results

match expectations. The code would use a random number seed to ensure reproducibility of the model

results.  

EPA will likely use the Leggett model (Leggett, 1993) as the PbB model for estimating both childhood

and adult changes in PbB level. The Leggett model, in contrast with the EPA Integrated Exposure Uptake

Biokinetic (IEUBK) model, allows incorporation of short‐term (less than one month) changes in exposure

levels and modeling of both children and adults. EPA is considering updating the tissue volumes and key

age‐dependent pharmacokinetic parameters used in the Leggett model. If these revisions are made,

model performance will likely be validated using key bone and PbB data sets, including the National

Health and Nutrition Examination Survey (NHANES).

Figure 3. Modeling Framework for Exterior Renovation Activities
Framework for Identifying and Evaluating Lead‐Based Paint Hazards from Renovation, Repair, and Painting

Activities in Public and Commercial Buildings

US EPA A‐5 May 2014

Figure 4. Modeling Framework for Interior Renovation Activities
Framework for Identifying and Evaluating Lead‐Based Paint Hazards from Renovation, Repair, and Painting

Activities in Public and Commercial Buildings

US EPA A‐6 May 2014

References

Leggett RW. (1993). An age‐specific kinetic model of lead metabolism in humans. Environmental Health

Perspectives 101:598–616.  

NRC 2009. Science and Decisions: Advancing Risk Assessment (The “Silver Book”). National Academy of  

Sciences. Washington, DC: National Academy Press.

http://www.nap.edu/catalog.php?record_id=12209

US EPA. (1992). Guidelines for Exposure Assessment. U.S. Environmental Protection Agency, Risk

Assessment Forum, Washington, DC, EPA/600/Z‐92/001.

US EPA. (2009). AERMOD modeling system “version 09292” [Software]. US Environmental Protection

Agency.

US EPA. (2010b). Proposed Approach for Developing Lead Dust Hazard Standards for Residences. SAB

Consultation Draft. Washington, DC: US Environmental Protection Agency, Office of Pollution

Prevention and Toxics (OPPT). Prepared for July 6–7, 2010 consultation.  

US EPA. (2014). Framework for Human Health Risk Assessment to Inform Decision Making. U.S.

Environmental Protection Agency, Risk Assessment Forum, Washington, DC, EPA/100/R‐14/001.
Framework for Identifying and Evaluating Lead‐Based Paint Hazards from Renovation, Repair, and Painting

Activities in Public and Commercial Buildings

US EPA A‐7 May 2014

Appendix B. Variables Being Considered for Use in the Analysis and Designation

of Scenario or Monte Carlo Variables in the Model Framework

Variable   Scenario or Monte Carlo (MC)

Exterior Interior

Renovation Characteristics:  

Renovation Activity Scenario    Scenario   

Containment options Scenario    Scenario   

Containment efficiency MC    MC   

Size of crew performing renovation

MC   

N/A8 Fraction emitted as aerosol by renovation activity MC   

Fraction emitted as bulk by renovation activity MC   

Work room loading per square foot disturbed, post

work

N/A9 MC   

Work room loading per square foot disturbed, post

cleaning MC   

Renovated building characteristics:  

Use type of renovated building

N/A

Scenario   

Job size within renovated building Scenario   

Location of person within building (in workspace or

adjacent) Scenario   

Time spent in building   MC   

Location of job in building MC   

Size of renovated building   Scenario    N/A

Fraction of renovated building that is glass MC    N/A

Containment Area

MC   

                                                            

8 Variable not Required for Interior Analysis   9 Variable not Required for Exterior Analysis  
Framework for Identifying and Evaluating Lead‐Based Paint Hazards from Renovation, Repair, and Painting

Activities in Public and Commercial Buildings

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Variable   Scenario or Monte Carlo (MC)

Exterior Interior

Vintage of renovated building Scenario    Scenario   

Lead content in paint MC    MC   

Layers of paint on wall

MC    N/A

Climate region MC   

Rain frequency N/A

MC   

Obstruction Adjustment MC   

Receptor building characteristics:   

Distance of receptor from renovated building Scenario    N/A

Receptor use type Scenario   

Same as renovated

building use type

Time spent in building   MC   

Same as renovated

building time spent

Ceiling height MC    MC   

Area of building MC    N/A

Receptor location (urban or rural): NEW Scenario   

N/A

Location of receptor relative to renovated building MC   

Vintage of receptor building MC   

Height of receptor building MC   

Ground type (hard surface or soil): NEW

MC   

Background Media Concentrations:

Background air concentrations

MC    MC   

Background dust lead loadings by vintage MC    MC   

Background soil concentration by vintage MC    MC   
Framework for Identifying and Evaluating Lead‐Based Paint Hazards from Renovation, Repair, and Painting

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Variable   Scenario or Monte Carlo (MC)

Exterior Interior

Dust Model Variables:

Cleaning frequency   MC    MC   

Percentage of receptor that is carpeted   MC    Scenario   

Floor dust lead loading to concentration conversion

MC    MC   

Floor cleaning efficiency (carpets and hard surfaces) MC    MC   

Air Exchange Rate   MC    N/A

Particulate Track‐in Rate   MC   

Fraction of Particulate on Doormat

MC    MC   

Fraction Bulk

MC    MC   

Track‐in Porosity MC    MC   

Track‐in Depth MC    MC   

Track‐in Rain Efficiency MC    MC   

Dust Model Penetration

MC   

N/A

Dust Model Resuspension MC   

Dust Model Deposition MC   

Volume of building MC   

Blood Lead Model Variables:

Blood lead model inputs MC    MC   

Concentration Response Curves:

IQ equation MC    MC   

Other health endpoint equations MC    MC   
Framework for Identifying and Evaluating Lead‐Based Paint Hazards from Renovation, Repair, and Painting

Activities in Public and Commercial Buildings

US EPA A‐10 May 2014

Appendix C. Preliminary Analysis  

EPA performed a limited set of preliminary analyses to determine the impact of different variables on

incremental IQ and blood lead (PbB) change estimates for children. EPA is considering similar analyses

for adults. The preliminary analysis was deterministic and does not fully account for variation in

scenarios evaluated. Therefore, preliminary analysis results are not representative of all scenarios that

could be analyzed. This analysis provided an initial assessment of the variables that may require

characterization using distributions (higher impact variables) versus those variables that may be

parameterized using a single point estimate. See Appendix B for the proposed characterization of

variables as scenario ‐ requiring only a point estimate at each proposed value for the scenario ‐ or

Monte Carlo (MC) ‐ requiring an entire distribution to describe the important range of the variable. EPA

will determine whether these preliminary results are reproducible once more robust analyses are

performed. Therefore, the preliminary findings reported herein should not be construed as final and

may change pending the subsequent and more comprehensive analyses.

Figures 5 and 6 show the range of results from the interior analysis, where trends based on the time

spent in the building and the square footage of the room are shown. The data points are separated by

color according to whether or not the exposed child was allowed in the workspace during the

renovation. These metrics are represented as “incremental” changes, indicating they represent the

change related to the renovation. The metrics are incremental IQ change, averaged over ages 1 through

7, for a child who experiences a renovation at age 1. In other words, the hypothetical child experiences

the renovation at age 1, which results in a short‐term spike in blood lead. The child's blood lead then

returns to the pre‐renovation level, typically within 1 year. For this preliminary analysis, the child's

AVERAGE blood lead, over ages 1 through 7, is then used to approximate the actual long‐term impact on

the child's IQ.

Figure 5 shows that the incremental IQ changes and PbB levels are highly sensitive to the amount of

time the exposed person spends in the building. The amount of time that children spend in P&CBs will

vary. Most P&CBs where young children would spend longer amounts of time are COFs, and are already

regulated. The ranges of time spent values in Figure 5 represent a hypothetical range from low to high,

and would be refined for the final analysis.  

Figure 6 shows that exposure concentrations that lead to incremental IQ and PbB changes tend to

increase with decreasing room size, although this is not strictly observed across all the different room

sizes. In addition to the room sizes varying, the ceiling heights were also varied in an effort to represent

actual room types. Examples include hospital rooms (smaller area, higher ceiling), offices (smaller area,

lower ceiling), and larger retail spaces (larger area, higher ceiling). Thus, the trend is due to both the

floor area and the ceiling height.  
Framework for Identifying and Evaluating Lead‐Based Paint Hazards from Renovation, Repair, and Painting

Activities in Public and Commercial Buildings

US EPA A‐11 May 2014

Figure 5. Trends in Incremental IQ Change & Time Spent for Children Inside P&CBs (Preliminary Analyses)

Time Spent Key:

1: 1 hour per month

2: 1 hour per week

3: 1 hour per day, 2 days per week for four

weeks

4: 2 hours per day, 3 days per week, for 8

weeks

5: 59 hours straight

6: 2.75 hours per day, 7 days a week

7: 24 hours a day, 1 day per week

Figure 6. Trends in Incremental IQ Change & Room Size for Children Inside P&CBs (Preliminary Analyses)

Room Size Key:

1: 15 m2

2: 30 m2

3: 35 m2

4: 135 m2

5: 825 m2

6: 1600 m2