FINAL REPORT

on

ELECTROSTATIC CLOTH AND WET CLOTHS

FIELD STUDY IN RESIDENTIAL HOUSING

EPA Contract No. EP-W-04-021

Work Assignment 1-07

Prepared for

Daniel M. Reinhart

EPA Work Assignment Manager

Prepared by

BATTELLE

505 King Avenue

Columbus, Ohio 43201

December 28, 2005
Final Report i December 28, 2005

TABLE OF CONTENTS

Page

EXECUTIVE SUMMARY ............ ............ ............ ............ ............ . . iii

1.0 OBJECTIVE ............ ............ ............ ............ ............ ..... 1

2.0 BACKGROUND ............ ............ ............ ............ ............ ... 1

2.1 EPA Purpose ............ ............ ............ ............ .......... 1

2.2 History and Motivation for Development of W hite Glove Clearance

Test with Disposable Cleaning Cloths ............ ............ ............ ... 2

2.2.1 Description of the Protocol ............ ............ ............ ..... 3

2.2.2 Potential Issues with the Protocol ............ ............ ............ 3

2.3 Summary of Prior W ork Completed to Date ............ ............ ........... 5

2.3.1 Round Robin Study ............ ............ ............ ........... 6

2.3.2 First Controlled Room Study ............ ............ ............ .... 7

2.3.3 Pilot Field Study in Vacant Buildings ............ ............ .......... 9

2.3.4 Second Controlled Room Study ............ ............ ............ 11

3.0 STUDY DESIGN ............ ............ ............ ............ ............ . 14

3.1 Study Data Quality Objectives ............ ............ ............ ........ 15

3.2 DCC/W G Clearance Protocol as Implemented in the Field Study ............ ..... 16

3.3 Implemented Field Study ............ ............ ............ ............ 19

3.4 QAPP Modifications ............ ............ ............ ............ .... 22

4.0 FIELD DATA COLLECTION ............ ............ ............ ............ .... 25

4.1 Site Selection ............ ............ ............ ............ ......... 25

4.2 Sampling Locations and Conditions ............ ............ ............ .... 26

5.0 LABORATORY ANALYSIS ............ ............ ............ ............ ..... 29

5.1 Review of Analytical Methods ............ ............ ............ ......... 29

5.2 Laboratory QC Results ............ ............ ............ ............ . . 29

6.0 ANALYSIS RESULTS ............ ............ ............ ............ ......... 33

6.1 Graphical and Tabular Summaries of Results ............ ............ ........ 33

6.2 Results by Data Quality Objective ............ ............ ............ ..... 39

6.2.1 Data Quality Objective 1 ............ ............ ............ ...... 39

6.2.2 Data Quality Objective 2 ............ ............ ............ ...... 41

6.2.3 Data Quality Objective 3 ............ ............ ............ ...... 46

6.2.4 Data Quality Objective 4 ............ ............ ............ ...... 50

6.3 Additional Results and Discussion ............ ............ ............ ..... 51

6.3.1 Effect of Reaching White Glove on Efficacy of Treatment ............ .... 52

6.3.2 Representativeness of Field Study Locations to R&R Population ........... 52

7.0 CONCLUSIONS ............ ............ ............ ............ ............ . 54

8.0 PEER REVIEW ............ ............ ............ ............ ............ . . 56

8.1 Peer Review Background ............ ............ ............ ............ 56

8.2 Peer Review Results ............ ............ ............ ............ ... 57

9.0 QUALITY ASSURANCE ............ ............ ............ ............ ....... 60
Final Report ii December 28, 2005

TABLE OF CONTENTS (continued)

Page

List of Figures

Figure 1. W hite Glove Clearance Testing Protocol in an R&R Environment ............ ..... 4

Figure 2. W hite Glove Clearance Testing Protocol for Field Study in Residential

Housing ............ ............ ............ ............ ............ . 17

Figure 3. Process Flow Diagram of Sampling for Residential Field Study ............ ...... 21

List of Tables

Table 1. Field Study Floor Sampling ............ ............ ............ .......... 27

Table 2. Field Study Sill Sampling ............ ............ ............ ............ 28

Table 3. Field Blank Sam ple Results ............ ............ ............ .......... 30

Table 4. Sampling Results from Battelle Laboratory Spike QC Samples ............ ...... 31

Table 5. Analytical Laboratory QC Sam ple Results ............ ............ ........... 32

Table 6. Counts of Surfaces Over or Under Clearance Standards by Treatm ent,

Pre-Protocol Lead Loading, and White Glove Status ............ ............ ... 37

Table 7. Overall DCC/W G Clearance Protocol Success Rates by Treatment ............ ... 38

Table 8. Covariate Levels for DCC/W G Clearance Protocol Failures Com pared to All

Surfaces ............ ............ ............ ............ ............ . 48

Table 9. Comparison of Wet DCC/WG Clearance Protocol Performance with Two

Commercially Available Cleaning Solutions and Water ............ ............ . 49

Table 10. Average Number of DCCs Used ............ ............ ............ ...... 51

List of Appendices

Appendix A. Quality Assurance Project Plan

Appendix B. Round Robin Study Report

Appendix C. First Controlled Room Study Report

Appendix D. Armstrong/Seneca Pilot Field Study Presentation

Appendix E. Second Controlled Room Study Report

Appendix F. Sample Data

Appendix G. Photographs for Floors
1Window troughs are part of lead abatement clearance testing but were not included in

this study because EPA does not intend to regulate them in renovation and remodeling situations.

Final Report iii December 28, 2005

EXECUTIVE SUMMARY

An innovative approach to lead clearance testing was developed and tested for use after

renovation and remodeling projects. This new approach to clearance testing is intended to serve

as an alternative to the wipe sampling clearance method currently recommended after renovation

and remodeling projects. It is hoped that the new approach will provide a viable alternative

method for lead clearance testing that is faster and less expensive than the current method. The

new method was tested on floors and window sills1 at 31 urban residential sites in two large

urban cities where lead hazard reduction work had recently been conducted.

The new lead clearance protocol was tested with dry electrostatic and wet detergent-based

disposable cleaning cloths (DCCs). Although DCCs were developed for light household

cleaning, they were used here as sampling tools in the new clearance protocol. The DCC

products employed for this study were all commercially available products purchased at local

retail stores.

The new clearance protocol utilizes a DCC to sample an entire floor or window sill, and a

visual assessment of the used DCC follows. If the DCC looks dirty or discolored (compared to a

reference standard), resampling with a fresh DCC is required. When the DCC remains nearly

white after use, the surface is judged clean enough to pass clearance. The visual assessment has

been named the ‘white glove’ test and the new clearance testing method is called the disposable

cleaning cloth/white glove (DCC/WG) clearance protocol. With the DCC/WG clearance

protocol, an entire floor or window sill is sampled rather than sampling a small area. Therefore,

the judgment about the used DCC passing or failing White glove reflects the status of the entire

floor or window sill surface.

The central question asked by this field study is whether sampling with DCCs and

passing the white glove test is indicative that the floor or window sill would pass standard

clearance testing with wipes. Side-by-side pairs of wipe samples were collected before and after

each DCC/WG clearance protocol and analyzed for lead content to evaluate the efficacy of the

new clearance method. Of particular interest was an assessment of whether the average lead

loading from the two ASTM wipe samples fell below 40 μg/ft2 for floors and below 250 μg/ft2 

for window sills.

The results of this field study indicate that the DCC/WG clearance protocol offers a

promising alternative for clearance testing of smooth and cleanable surfaces in residential

renovation and remodeling projects. The data demonstrate that when white glove is achieved,

the new protocol affords a quick, low-cost, and reasonably accurate method for concluding that

lead clearance standards have been met for floors and window sills.
Final Report 1 December 28, 2005

1.0 OBJECTIVE

The objective of the current field study in residential housing is to determine to what

extent, and under what conditions within renovation and remodeling (R&R) work, an

electrostatic cloth/wet cloth clearance protocol used along with a white glove visual test can

obtain comparable results to current dust-lead clearance protocols based on results of wipe

sampling. The approach of the white glove test is that the electrostatic or wet cloth must be

essentially free of visible dust after sampling in order to pass clearance. In this way, the new

white glove protocol might function as a simple, quick and inexpensive approach for clearance

testing.

2.0 BACKGROUND

This report primarily presents the results from limited field testing with a potential new

clearance protocol that EPA is calling the disposable cleaning cloth/white glove (DCC/WG)

clearance protocol. However, this report also presents the results of other pilot studies EPA

conducted leading up to the current field study. These prior results are summarized later in

Section 2, as well as the appendices of this report. Section 2.1 discusses EPA’s purpose in

performing this field study, while Section 2.2 provides background on current clearance testing

and defines the alternative DCC/WG clearance protocol. Section 2.3 summarizes the earlier pilot

results from studies of white glove clearance testing using various disposable cleaning cloth

protocols. Sections 3 through 7 provide the detailed results from the current DCC/WG field

testing study. Section 3 presents the study design, while Sections 4 and 5 describe the field

sampling and laboratory analysis protocols. Section 6 presents the study results, as well as the

interpretation of the data relative to the study objectives. Section 7 provides discussion and

conclusions based on the study results. Section 8 summarizes the key inputs from a peer review

panel that evaluated the study. Section 9 addresses Quality Assurance. The Appendices A

through E present supporting material in the form of quality assurance project plans and previous

pilot study reports. Appendix F contains the wipe sample data for the field study. Appendix G is

a picture gallery of the floors sampled during the study.

 

2.1 EPA Purpose

EPA currently is developing technical guidance to help prevent potential lead poisoning

of household residents resulting from residential renovation and remodeling (R&R) activities. 

Evidence exists that R&R work activities may release hazardous levels of leaded dust and debris

into residential environments. In one study, R&R activities such as demolition, window

replacement and surface preparation were found to release leaded dust onto horizontal surfaces at

levels as high as 40,000 :g/ft2

 or more (see EPA’s report on Lead Exposure Associated with

Renovation and Remodeling Activities: Environmental Field Sampling Study, Volume I:

Technical Report, EPA 747-R-96-007, May, 1997). Effective cleanup and cleaning verification

following any such R&R activity is essential for protection of household occupants, especially

young children, who are often most highly exposed and most vulnerable to the adverse health

effects of lead. 
Final Report 2 December 28, 2005

Cleanup methods commonly used by R&R professionals (e.g., broom sweeping and

vacuum cleanup) can sometimes be ineffective in reducing lead dust loadings to safe levels. In

limited testing, EPA concluded that residual lead levels after R&R activities followed by broom

or vacuum cleanup could often be well over 100 :g/ft2

 on floors (see EPA report 747-R-96-007,

May, 1997). A fast, inexpensive and reliable method for assessing post-R&R cleanup is an

important component of EPA’s formulation of R&R guidance. To be effective, a clearance

protocol needs to meet several criteria, including:

• provide quick feedback,

• be relatively inexpensive and easy to conduct,

• possess good predictive accuracy concerning surface lead loadings, and

• be compliant with EPA regulations.

It is envisioned that some R&R work and cleanup will be conducted by homeowners

themselves and various contractors (e.g., painters, carpenters) who do not necessarily fall within

the jurisdiction of existing EPA, HUD or other federal regulations. These individuals may also

have limited training and familiarity with existing best practices for lead hazard reduction and

lead poisoning prevention. Therefore, it is important that EPA’s R&R regulations, guidance and

associated protocols and methods are intuitive, relatively easy to implement, and at the same time

accurate and effective for their intended purposes. The R&R clearance protocol is one of these

important elements of EPA’s R&R program.

2.2 History and Motivation for Development of White Glove Clearance Test with

Disposable Cleaning Cloths

The clearance testing method currently used in abatement or lead hazard control settings

relies on ASTM dust wipe sampling. The objective of clearance testing is to verify that cleanup

has reduced lead to safe levels below the applicable EPA standards (see 66 FR 1206, January 5,

2001). Clearance testing requires that a dust collection technician take single wipe samples from

the floor, window sill, and window trough in areas where lead hazard control work and cleanup

activities have been performed.

Dust wipe samples using wipes that meet the ASTM criteria are sent to an accredited 

laboratory recognized by EPA/NLLAP for analysis. If the lead measured in any of the wipes

indicates a lead loading greater than or equal to EPA’s clearance standards (i.e., 40 μg/ft2 on

floors, 250 μg/ft2 on sills, and 400 μg/ft2 in troughs), the cleanup is declared to have failed and

the cleanup and clearance sampling process is repeated until acceptable wipe measurements are

reached for all sampled surfaces.

Because of the large number of R&R projects performed in the country, there are

potential cost and scheduling concerns associated with the idea of applying standard abatement

or lead hazard control clearance testing in a residential R&R environment. As such, EPA

decided to investigate whether a white glove protocol performed with disposable cleaning cloths

might be useful for conducting clearance testing in an R&R setting.
Final Report 3 December 28, 2005

2.2.1 Description of the Protocol

EPA has developed an alternative method for lead clearance testing to verify the efficacy

of cleanup after R&R projects. This clearance method does not require wipe sampling to

determine if lead loadings after cleanup are acceptable. Instead, the new clearance sampling

method uses disposable cleaning cloths (DCCs) as clearance testing tools. These commercial

products are available as dry electrostatic cloths (e.g., Swiffer®, Grab-itTM) or as wet mopping

pads that function with the aid of a detergent (e.g., Swiffer®WetJet®, Clorox®Ready Mop®). 

Dry and wet DCC products come in different sizes and shapes, but all involve mopping with a

dust collection device. Both dry electrostatic and wet DCCs were evaluated in the current field

study.

The proposed DCC/WG clearance protocol is relatively simple to conduct and intuitively

easy to understand. It involves thoroughly (and uniformly) mopping the entire floor or window

sill with a DCC. Next the used DCC is visually inspected. If the cloth retains its pre-use, nearwhite appearance, the floor or window sill is judged to pass clearance and no additional treatment

or sampling is necessary. (A comparison photograph is provided which shows the greatest

amount of soiling which should be tolerated to still conclude a near-white appearance in the

visual assessment.) If the DCC visually appears more soiled than the comparison photograph, 

mopping of the entire floor (or window sill ) is repeated with a new cloth. After this mopping,

the visual test is repeated using the replacement cloth. This sequence of mopping and visually

assessing the used cloths is repeated until a cloth retains its near-white appearance after being

used to mop the surface.

Figure 1 is a flow chart diagram describing the DCC/white glove clearance protocol. It

illustrates the sequence of steps taken to test each floor or window surface. In addition to the

central instructions regarding the mopping and comparison to visual standards described above,

the figure provides other important steps for acknowledging the limitations of when the protocol

may be used. These issues are discussed further below.

2.2.2 Potential Issues with the Protocol

In the new clearance testing protocol, DCCs fulfill two functions: (1) they provide an

easy way to immediately assess the lead clearance status of floors and window sills, and (2) they

continue removing dust/lead that remains after the primary cleanup. Even when cleanup has

failed to remove some dust (and potentially lead), the DCC protocol has the potential to finish

the cleaning job. However, it must be emphasized that the DCC clearance protocol is not

intended to replace or supplement the primary cleanup of the site. The DCC/white glove

protocol is being evaluated as a tool for identifying when cleanup has been effective. Clearly, the

DCC does continue to remove residual lead dust that cleanup may have missed, but this is

viewed as a bonus and not a core function of the protocol.
Final Report 4 December 28, 2005

Figure 1. White Glove Clearance Testing Protocol in an R&R Environment
Final Report 5 December 28, 2005

The implicit assumption with the white-glove test is that a near-white DCC (dry or wet) 

will prove to be a reliable predictor of successful clearance. In other words, it is assumed that a

used DCC with no visible dust will accurately indicate that lead loadings fall below the clearance

standard. Hazardous lead loadings on floors may not produce visible dust residues, but it is

hypothesized that a wet or dry DCC, when mopped over an entire floor, will capture, accumulate,

and amplify the visual appearance of low levels of lead dust. In this way, lead dust that may have

been invisible on floors may become visually evident on the white cloth.

 Experience has shown that some floor or window surfaces accumulate a dried layer of

strongly adhering dirt/grime that only an intensive cleaning or scrubbing can remove. It must be

emphasized that in EPA’s evaluation of the DCC/WG protocol, sampling with the DCC was

never intended to be used on these challenging surfaces. This is why, after completion of R&R

work, the first question that must be addressed concerns the condition of the floor or window sill

surface to be tested. Specifically, is the surface smooth and cleanable? A surface that has

numerous cracks and crevices or a surface missing much of its finish will invariably be

unsuitable for DCC clearance testing as it would not be considered smooth and cleanable. This

kind of surface would require refinishing, replacement, or some other appropriate remedial work.

2.3 Summary of Prior Work Completed to Date

EPA has been conducting technical studies related to the development of a white glove

test for the past five years (beginning in 2001). A central question of concern is how effective

disposable cleaning cloths are for sampling. That is, how well do these cloths pick up leaded

dust? Early in this work, EPA considered two primary ways of evaluating this question. First,

EPA evaluated how much leaded dust a DCC could be expected to pick up (i.e., collect) from the

total amount of dust available on a horizontal surface (i.e., floors or window sills) in a controlled

laboratory setting. Second, EPA evaluated how likely it is that a DCC will pick up any residual

leaded dust that might be left on a horizontal surface after R&R cleanup, so that the surface could

subsequently be expected to pass lead clearance testing. While these were two central questions,

EPA also considered related issues such as chemical analysis protocols for analyzing DCCs for

lead content, and the ability of sampling technicians to visually and accurately determine when

DCCs are free of leaded dust when a white glove condition has been reached.

Leading up to the current field study, EPA conducted four other studies that each

examined different aspects of the questions listed above. The reports from these four studies,

which are provided in Appendices B through E, cover the following topics, respectively:

• Chemical analysis protocol for analyzing DCCs for lead content

• Collection efficiency of ASTM dust wipes and DCCs in a controlled room setting,

and accuracy of visual assessments for judging the amount of leaded dust on a DCC.

• Efficacy of DCCs for collecting leaded dust in a real-world setting and reducing

residual dust-lead to levels below clearance standards
Final Report 6 December 28, 2005

• Efficacy of different dry and wet DCC white glove protocols for reducing a variety of

leaded dust loadings to levels below clearance standards.

In the progression of these pilot studies, questions related to the DCCs were first

investigated in controlled laboratory conditions, and then in limited real-world testing outside of

the laboratory. The first two studies focused on the ability of an individual DCC to collect a

known amount of leaded dust from a smooth surface under relatively ideal conditions. Those

favorable conditions included reasonably low lead loadings and sampling from linoleum floors

that were in good condition. The third and fourth pilot studies then presented increasing

challenges to the evolving DCC/WG protocol. In the third study, sampling was conducted in real

buildings that represented residential R&R settings in some ways, but also differed from those

R&R settings in other ways. And, in the fourth pilot study, the DCC/WG protocol was

challenged with higher lead loadings back under controlled laboratory conditions.

In total, these preliminary studies indicated that a white glove DCC protocol had the

potential to serve a useful role in the R&R program. However, the protocol had not yet been

tested in the field, in real-world residential housing by dust sampling technicians. Therefore, the

current field study also was conducted to help fill this information gap. Results from the four

preliminary studies are briefly summarized in the following Sections 2.3.1 through 2.3.4, while

the design and results from the current field study are discussed in Sections 3 through 7.

2.3.1 Round Robin Study

As noted above, one question of central importance for the evaluation of the white glove

protocol was that concerning the amount of available leaded dust on a horizontal surface that

DCCs could be expected to collect. One direct way to evaluate this question (and the approach

taken in the First Controlled Room Study - see Section 2.3.2 and Appendix C) is to “spike” (i.e.,

apply in a controlled fashion) a known amount of leaded dust onto a clean horizontal surface, and

then pick the dust back up with a DCC and determine how much dust is collected. However, in

order to determine how much leaded dust the DCC collected, a chemical analysis protocol was

needed to determine the lead content of a DCC. Such a laboratory protocol was the focus of the

Round Robin Study.

Early in 2001, EPA funded the development of a laboratory protocol for digesting and

chemically analyzing DCCs for lead content. The protocol was developed by the University of

Cincinnati and Battelle. Subsequently, Battelle conducted the Round Robin Study to assess the

accuracy of the new protocol. The primary objective of this study was to confirm with a high

degree of confidence that the recovery rates associated with the DCC chemical analysis protocol

are within the 80-120% recovery range. An additional objective of the study was to examine

possible nuisance factors affecting the lead recovery. Factors considered were the cloth brand or

manufacturer, the amount of lead spiked on the cloth, the laboratory type, and the analytical

method of lead detection.
Final Report 7 December 28, 2005

For the final study design, four laboratories (two commercial, NLLAP-accredited labs and

two research-oriented labs) analyzed three replicates at each of four lead spike levels (blank, low,

medium, and high) on each of three different cloth brands (Proctor and Gamble®’s SwifferTM,

Vileda®

 ExstaticTM, and Pledge®

 Grab-ItTM). Each of the four laboratories was to digest and

analyze 36 spiked DCCs. All the labs agreed to digest the cloths according to the protocol set

forth by Battelle. All four labs were to conduct Flame-AA analysis of the resulting digestates. In

addition, the two research laboratories were to conduct ICP-MS analysis on aliquots of the same

digestates. The results from the ExstaticTM DCCs were excluded from the data analysis due to

complications experienced by the laboratories when digesting these cloths. All other data were

included in the final results.

The study data were analyzed with a statistical model to assess the probability that a lead

recovery between 80-120% can be achieved with different DCCs, laboratories, lead levels, and

analytical instruments. In most cases, the digestion and analysis protocol was found to be

feasible, and in some cases the protocol worked very well (i.e., there was a high probability that

the recovery would be between 80-120%). However, in the case of one type of cloth (i.e., the

ExstaticTM) digestion was a serious problem, and in other cases certain types of cloths,

laboratories, and/or analytical instrumentation do not appear to assure lead recovery in the 80-

120% range with high probability. Overall, the research laboratories were able to perform the

protocol with greater success than the randomly selected NLLAP laboratories; the Grab-ItTM

cloths yielded recoveries in the 80-120% range with higher probability; and the ICP-MS

analytical instrumentation yielded recoveries in the 80-120% range for a broader (especially

lower) range of lead levels. The commercial labs, Swiffer cloths, and Flame-AA analysis were

generally associated with lower probabilities of achieving the targeted 80-120% recovery.

2.3.2 First Controlled Room Study

Knowing from the Round Robin Study that it is feasible to digest and chemically analyze

some DCCs for lead content, EPA was next able to perform a study to directly assess the amount

of leaded dust that DCCs might be expected to pick up from a horizontal surface. This

assessment was performed in the First Controlled Room Study. The primary objectives of this

study were to gauge the efficiency of disposable cloths when the dust was collected in a manner

similar to standard clearance testing, and to assess the feasibility of utilizing a visual assessment

to determine the amount of dust present on a DCC. Also, an additional objective of this study

was to gauge the sampling efficiency of standard wipes. Earlier work by EPA (see Laboratory

Evaluation of Dust and Dust Lead Recoveries for Samplers and Vacuum Cleaners, Volume I:

Objectives, Methods, and Results, EPA 747-R-94-004A, March, 1995) suggested that the

sampling efficiency of wipes is about 60-65%.

The basic approach of this study was to apply (i.e., “spike”) a known amount of leaded

dust onto a horizontal surface and then determine how much of the dust a DCC might be

expected to pick up. The study design consisted of two replicates at each of two lead loading

levels (40 :g/ft2 and 100 :g/ft2) using two wipe methods (standard ASTM wipes and one brand

of ECC) from four sampling regions (1 ft2

 and 4 ft2

 for ASTM wipes; and 1 ft2

, 4 ft2

, 24 ft2

, and
Final Report 8 December 28, 2005

48 ft2

 for ECCs). ASTM wipe primary samples were taken from each 1 ft2

 section of the

sampling regions, and two primary ECCs were taken, one right after the other, from each

sampling region. In addition, following the primary samples, secondary ASTM wipe samples

were collected to assess the amount of any residual dust that might have been left after primary

sampling. All cloths were digested and analyzed by Battelle’s laboratory using ICP-MS.

The results from the sampling study indicated that the efficiency of the DCCs was not

statistically different from the efficiency of the ASTM wipes, which currently are used in

regulations that establish hazard and clearance levels. The efficiency for both was found to be

65-70%. Thus, the DCCs worked as well as the current standard wipes to collect settled dust in a

controlled room setting. Analysis of the lead collection efficiencies of the DCCs over the four

sampling region sizes (from 1 ft2 to 48 ft2) at the two lead loadings (40 :g/ft2 and 100 :g/ft2) 

revealed a small decline in efficiency as the dust lead levels increased. However, this decline

was not statistically significant.

The basic study approach for the visual assessment was to develop photographic

standards depicting different amounts of leaded dust, and then to ask several sampling

technicians to compare the appearance of different real DCC samples with the photographic

standards. A total of 444 visual assessments of the amount of dust present on 45 ECCs were

performed by 10 Battelle staff. The amounts of dust on the cloths varied from about 0 mg to 500

mg. For each ECC, each staff member visually examined the amount of dust present and

categorized the amount according to a set of 11 photographic standards (except for one

technician who did not evaluate six blank cloths that he had helped prepare). The true amount of

dust on each ECC also was measured via chemical analysis of the ECCs (along with numerical

back-calculations using the known lead concentration of the standard reference material dust)

after the visual assessments had been completed. Out of the 444 visual assessments, 212

assessments correctly selected the amount of dust (i.e., the correct photographic standard). In

addition, 119 other visual assessments missed the correct amount of dust by just one

photographic standard (approximately 50 mg of dust) on the high or low side. In total, 331 of the

444 visual assessments (i.e., 75%) judged the correct amount of dust on each DCC to within one

photographic standard, or within about 50 mg of dust.

Results from the First Controlled Room Study indicated that DCCs can pick up leaded

dust from horizontal surfaces with the same collection efficiency (approximately 65-70%) as

standard ASTM dust wipes. Furthermore, DCCs can achieve this same collection efficiency for

larger surfaces. In addition, visual assessment of DCCs appears to be a feasible tool for

determining the amount of dust on a DCC, and hence, for determining when DCC sampling has

reached a white glove status (i.e., no significant dust present on the DCC). It should be noted

that the First Controlled Room Study only included testing of dry electrostatic cloths; no wet

disposable cleaning cloths were tested.
Final Report 9 December 28, 2005

2.3.3 Pilot Field Study in Vacant Buildings

Results from the Round Robin Study and First Controlled Room Study indicated the

potential feasibility of utilizing DCCs to collect residual dust from horizontal surfaces. 

However, both of these studies were conducted in controlled laboratory settings. Therefore, it

was important for EPA to begin to assess how well a white glove DCC protocol might perform in

real-world conditions. As a first step in this assessment, EPA conducted the Pilot Field Study in

Vacant Buildings. By necessity, this study changed the focus of the DCC evaluation to account

for uncontrolled, real-world conditions as opposed to the controlled, laboratory conditions of the

first two studies. In particular, a direct assessment of the amount of available dust that is

collected by a DCC can not be made in real-world conditions because the pre-existing amount of

leaded dust on the sampling surface is unknown. Also, pre-existing dust accumulates naturally

over time, rather than being spiked in a known amount by researchers. Therefore, the efficacy of

the DCC sampling protocol was evaluated by its ability to leave a horizontal surface suitably free

of leaded dust so that the surface would pass lead clearance testing.

To make this assessment, EPA required a large number of available horizontal surfaces in

a real-world setting where some amount of leaded dust was present. While investigating several

alternative locations at which to conduct this type of field work, EPA became aware of two large

vacant buildings likely to contain leaded dust. One building was the Seneca Hotel in Columbus,

Ohio, and the other was the Armstrong Vocational School in Washington, D.C. Both are older,

established structures likely to contain leaded dust, and both were vacant with plans for

renovation, so they were readily accessible for sampling teams.

The general study approach was to select a variety of horizontal surfaces, sample a

portion of each surface to determine the initial dust lead loading, apply the DCC protocol until a

white glove condition was achieved, and then sample a portion of the surface to determine the

residual dust-lead level and whether the surface would pass clearance testing. Because both the

Seneca Hotel and Armstrong School are relatively large structures, a variety of floor and window

sill surfaces constructed of different building materials were available for sampling. The

experimental design at the Seneca Hotel included 65 sampling locations consisting of eight

different uncarpeted, hard-floor surface types; 52 low-pile, carpeted sampling locations; and 101

wooden window sill sampling locations. Sampling at the Armstrong School included 101

sampling locations consisting of three different uncarpeted, hard-floor surface types. All

sampling in both the Seneca Hotel and Armstrong School was conducted with dry electrostatic

cloths; no wet disposable cleaning cloths were tested in these buildings.

The Seneca Hotel contained several flooring and window types that might reasonably be

found in residential housing. However, the Seneca had been empty for several months and was

in a relatively poor state of disrepair when testing was performed. This meant that the initial,

pre-testing lead levels were often high. Also, the existing dust was often quite thick and caked. 

Often the floors and window sills were heavily cracked, or boards and joints were separated. 

Additionally, there were a large number of rooms in the Seneca Hotel where low-pile carpeting

had been laid down to cover flooring that was in poor condition.
Final Report 10 December 28, 2005

Because of these and other limitations, the Seneca Hotel results must be interpreted with

caution. However, there were several relevant and interesting findings. Perhaps the most

significant was that in a large number of cases (35 of 37 cases) where the DCC/WG protocol was

applied to uncarpeted hard-floor areas that had pre-testing lead levels between 40 :g/ft2

 (i.e., the

clearance standard) and 100 :g/ft2, the lead level measured after the DCC/WG protocol was

below 40 :g/ft2

 (i.e., low enough to pass clearance testing). Although there is limited

information about lead levels in an R&R setting where clearance testing has failed (see Section

6.3.2), the current study suggests that when the pre-protocol lead levels are between 40 :g/ft2 and

100 :g/ft2, the lead levels after performing the DCC/WG protocol would be below the clearance

standard.

The Seneca Hotel results also were analyzed from the perspective of false negative and

false positive decision-making errors. In this context, a false-negative decision error was defined

as a situation where the DCC/WG protocol achieved a white glove condition (indicating that the

surface would probably pass clearance testing), but the post-protocol ASTM wipe sampling

indicated that the lead level was still above 40 :g/ft2 (i.e., that the surface would not pass

clearance testing). Considering potential decision errors in the other direction, a false-positive

decision error was defined as a situation where the DCC/WG protocol failed to achieve a white

glove condition after eight to ten moppings (indicating that the surface would probably fail

clearance testing), but the post-protocol ASTM wipe sampling indicated that the lead level was

actually below 40 :g/ft2 (i.e., the surface would pass clearance testing). When examining all of

the Seneca Hotel uncarpeted hard-floor results, a false-negative decision error rate of

approximately 30% was indicated (31 of 93 cases) and a false-positive decision error rate of

about 40% was found. These error rates include a range of pre-protocol lead levels (from less

than 40 :g/ft2

 to well over 1000 :g/ft2

) and a range of floor materials (e.g., wood, linoleum and

ceramic tile, marble and concrete).

The Seneca Hotel Study also provided an opportunity to collect similar DCC testing

information from window sills. In total, 101 window sills were tested with 93 of the sills

achieving a white glove condition. In a large number of cases (18 of 20 cases) where the

DCC/WG protocol was applied to window sills that had pre-testing lead levels between 250

:g/ft2 (i.e., the clearance standard) and 500 :g/ft2, the lead level measured after the protocol was

below 250 :g/ft2

 (i.e., low enough to pass clearance). Similar to the floor results discussed

earlier, these are cases where the DCC/WG protocol took pre-existing lead levels as high as

twice the clearance standard and pushed them after the protocol to levels below the clearance

standard. In terms of false-negative and false-positive decision error rates for the Seneca Hotel

window sills, the results indicated a false negative error rate of approximately 20% (16 out of 93

cases) and a false positive error rate of about 75% (6 out of 8 cases). Note that the high false

positive rate is based on very limited information.
Final Report 11 December 28, 2005

Pilot field testing of the DCC protocol also was conducted in the Armstrong Vocational

School in Washington, D.C. However, in this case, although initial inspection of the property

indicated that it was suitably representative of residential R&R conditions, the subsequent

detailed sampling and field work indicated that it probably was not an accurate surrogate for

these residential conditions. Although large floor surfaces with leaded dust were available, the

dust was commonly much greasier and more heavily caked than one would expect in a residential

setting after R&R work and the subsequent cleanup have been completed. In addition, the

percentage of pre-testing lead levels between 100 :g/ft2 and 1000 :g/ft2 was much higher in the

Armstrong School than in the Seneca Hotel.

Despite these limitations, the results from the Armstrong School have been included in

Appendix D because they may provide information about the performance of the DCC/WG

protocol under especially challenging conditions. In cases where the protocol was applied to

uncarpeted hard-floor surfaces that had pre-testing lead levels between 40 :g/ft2 and 100 :g/ft2,

post-protocol lead levels below 40 :g/ft2

 were achieved in a majority of cases (15 of 22 cases). 

In terms of false-negative and false-positive decision error rates for Armstrong School hard-floor

surfaces, the results indicated a false-negative error rate of 67% (8 out of 12 cases), and a false

positive error rate of 30% (55 out of 186 cases). In addition, because of the greasy and heavily

soiled floor conditions, there were relatively few cases where a white glove condition could be

achieved at all. Out of a total of 198 cases, the white glove condition after multiple DCC

moppings was only achieved in 12 cases (i.e., less than 10% of the time).

2.3.4 Second Controlled Room Study

Building upon the laboratory and field experiences of the three earlier studies, EPA

decided to conduct a Second Controlled Room Study that primarily investigated the ability of the

DCC/WG protocol to handle elevated pre-testing dust lead loadings. Both the First Controlled

Room Study and the Pilot Field Study in Vacant Buildings suggested that the protocol could

achieve good success on hard-floor surfaces in cases where the pre-testing dust-lead levels are

between 40 :g/ft2 (i.e., the clearance standard) and 100 :g/ft2. However, the Study in Vacant

Buildings suggested that the protocol was less successful at handling cases where the pre-testing

lead levels are above 100 :g/ft2

. But, these results were collected in vacant commercial

buildings rather than residential R&R settings. Therefore, the decision was made to investigate

the higher lead loadings back in a controlled room setting.

 The study took place in a controlled room setting at Battelle in which each of three

different 24 ft2 floor surface areas, following initial cleaning, was “spiked” with a known amount

of leaded dust (using two different standard reference materials; SRM #2584 = house dust with

1% lead, SRM #2589 = pulverized paint with 10% lead), subsequently mopped with disposable

cleaning cloths, and then subjected to wipe sampling. The wipe samples were chemically

digested and analyzed for lead content. The results of the laboratory analysis were used to

estimate the amount of lead remaining on the floor following the protocol. 
Final Report 12 December 28, 2005

Under the base protocol, a series of dry electrostatic cloths was used within the sample

area to collect the dust lead until a clean cloth was achieved after wiping the area (i.e., white

glove). Determination of this white glove condition was done by visual comparison to a

photographic standard. After white glove was achieved, four ASTM wipe samples were

collected from randomly selected 1 ft2 sections within the area, as well as from two random 1 ft2

areas on the perimeter of the sample region. Four lead loadings (40, 200, 600, and 1,600 :g/ft2

 )

were examined for each of two different standard reference materials. Each combination of lead

loading and standard reference material was examined for each of the three floor sample areas.

Testing was completed over 10 days in October, 2003.

In every testing sequence of the Second Controlled Room Study, the DCC/WG protocol

was continued until a white glove condition was achieved. Therefore, when interpreting the

results the conclusions are necessarily limited to the protocol’s ability to take pre-existing lead

levels that are well above the clearance standard and push them to levels below the clearance

standard. Along with this, an assessment can be made about the false-negative decision error

rate. However, no assessment of the false-positive error rate was possible in this study because a

white glove condition was achieved in every case. In addition, because some experience in the

previous studies indicated that several iterations with the DCCs might be required in some cases

to achieve the white glove condition, the Second Controlled Room Study also considered three

potential variations of the protocol in hopes that they might achieve the white glove condition in

fewer moppings.

The results with the base DCC/WG protocol indicated good success when the pre-testing

lead levels were either 40 :g/ft2

 or 200 :g/ft2

. In these cases, 47 of 48 tests resulted in posttesting lead levels below 40 :g/ft2

, implying a false-negative error rate of about 2% (i.e., 1 out of

48 cases). At higher lead levels, the results showed higher false-negative rates. When the pretesting lead level was 600 :g/ft2

, 15 of 24 tests resulted in post-testing lead levels below 40 :g/ft2

– a false-negative error rate of about 40% (i.e., 9 of 24 cases). And, when the pre-testing lead

level was 1600 :g/ft2, only 4 of 24 tests resulted in a post-testing lead level below the clearance

standard – indicating a false-negative error rate of more than 80% (i.e., 20 of 24 cases).

Supplemental testing with the three variations of the basic DCC/WG protocol was run at

the highest lead level of 1600 :g/ft2

 to investigate whether improvements in the false-negative

error rate could be achieved. The first protocol variation consisted of performing the base

DCC/WG protocol, and then after a white glove decision had been made, performing additional

moppings with two more dry DCCs. This first protocol variation led to some improvements with

17 of 24 cases resulting in post-testing lead levels below the clearance standard – a false-negative

error rate of about 30% (i.e., 7 of 24 cases).

The second protocol variation included everything from the first protocol variation (i.e.,

perform the base protocol, then two more dry DCC moppings) plus one additional mopping with

a wet ECC at the end. With this second protocol variation, all 12 tests that were performed

resulted in post-testing lead levels below the clearance standard – that is, a 0% false-negative

error rate.
Final Report 13 December 28, 2005

The third protocol variation included a somewhat simplified approach from the first two. 

Namely, the basic DCC/WG protocol was performed until a white glove decision was made, and

then one additional mopping was performed with a wet ECC at the end. This third protocol

variation resulted in 11 of 12 cases where the post-testing lead level was below the clearance

standard – indicating a false-negative error rate of about 10% (i.e., 1 out of 12).

In all cases, the concentration and form of lead in dust was not found to be a significant

covariate in explaining results.

Overall, results from the Second Controlled Room Study indicated that reasonably good

results can be expected (at least under controlled conditions) with the basic testing protocol that

employs dry DCCs when the pre-testing lead levels are as high as 200 :g/ft2. In addition,

including a wet sampling cloth after the basic dry DCC protocol may provide a reasonable means

of handling even higher pre-testing lead levels, with levels up to 1600 :g/ft2 being investigated in

this study.
Final Report 14 December 28, 2005

3.0 STUDY DESIGN

Following the work detailed in Section 2.3, the present field study was performed with a

primary objective of evaluating the real-world efficacy of a white glove clearance protocol using

disposable cleaning cloths. In simple terms, if disposable cleaning cloths remain near-white after

application to a surface, can we reliably conclude that lead loadings are at or below the clearance

standard? If the effectiveness can be empirically validated, then this protocol might prove a

legitimate option for clearance sampling in an R&R environment.

The study design and results sections in this report will refer to a Disposable Cleaning

Cloth/White Glove clearance protocol. This will be abbreviated as DCC/WG clearance protocol.

The DCC/WG clearance protocol is a general term that refers to the set of activities performed in

determining whether or not a surface wiped with cleaning cloths achieves white glove, and hence

meets clearance standards. This idea was presented and discussed in Section 2.2 and was

depicted graphically in Figure 1. Several important points apply to the DCC/WG clearance

protocol used in this field study:

• The protocol used in this evaluation is similar to what was done in previous studies

but not identical. To understand the specific details of the protocol execution for this

study, refer to Sections 3.2 and 3.3. See the appropriate appendices for references as

to how the protocol was performed in previous studies.

• The studies previously done for this protocol used mostly dry electrostatic cleaning

cloths (also called ECCs or ECs). However, it was discovered that the protocol might

be most effective when employing cleaning cloths that included a liquid detergent

rather than just ECCs. To reflect this broader population of potential cleaning cloths,

the term “ECC” has been replaced with the more generic “DCC”, for disposable

cleaning cloth. The two types of clothes are distinguished by calling them a wet DCC

or a dry DCC.

• To assess the impact of the critical question of protocol effectiveness as a function of

the type of cleaning cloth used, a design was created that tested implementation of the

same basic protocol but with different disposable cleaning cloth configurations, both

dry and wet. Commonly referred to throughout the following report as “treatments”,

they include:

• Dry DCC/WG clearance protocol (Max 15 cloths) on floors - Also known as the

dry treatment or dry protocol, this version of the protocol used only dry

(electrostatic) cloths attached to their appropriate manufacturers’ mop heads. For

time and cost reasons, if 15 cloths were used without reaching white glove, the

protocol was stopped and the surface categorized as ‘failed to reach white glove’. 
Final Report 15 December 28, 2005

• Dry+1 Wet DCC/WG clearance protocol (Max 15 dry DCCs) on floors - Also

known as the dry+1 wet treatment, this refers to the protocol that is the same as

the dry protocol except that one additional pass is made of the floor surface using

a wet DCC after the dry treatment is complete.

• Wet DCC/WG clearance protocol (Max 15 Cloths) on floors - Also known as the

wet treatment, this refers to the protocol using exclusively disposable wet cleaning

cloths attached to their appropriate manufacturers’ mop heads. The protocol was

stopped if white glove could not be achieved in 15 cloths.

• Dry DCC/WG clearance protocol (Max 3 Cloths) on sills - Also known as the dry

treatment or dry protocol, this version of the protocol used only dry (electrostatic)

cloths. Wiping was done by hand for sills. The protocol was stopped if white

glove could not be achieved in three cloths.

• Wet DCC/WG clearance protocol (Max 3 cloths) on sills - Also known as the wet

treatment, this refers to the protocol using exclusively disposable wet cleaning

cloths. Wiping was done by hand for sills. The protocol was stopped if white

glove could not be achieved in three cloths.

Note: the small sample surfaces of sills did not permit the evaluation of the dry+1 wet

treatment, as was done on floors.

The following sections describe the data quality objectives of the study (Section 3.1),

compare the DCC/WG clearance protocol for general application to that used in this field study

(Section 3.2), discuss the implemented study design (Section 3.3), and identify important

departures from the Quality Assurance Project Plan (Section 3.4). 

3.1 Study Data Quality Objectives

Four data quality objectives (DQOs) have been identified for this study. These represent

specific and measurable ways to evaluate the general hypothesis of the study. There are three

DQOs associated with a core assumption that the DCC/WG clearance protocol achieves a

“passing” condition, and one DQO for cases where this does not happen (i.e., white glove is not

achieved).

1. How does a DCC/WG clearance protocol “pass” result compare to a formal wipe

clearance sample result? 

a. The primary data quality objective of this study was to estimate the probability

(and corresponding 95 % lower confidence bound) that surfaces will achieve the

wipe sampling clearance standards, given that the surfaces have passed the white

glove condition. Separate estimates were obtained for hard floors and window

sills and for each treatment applied to these two types of surfaces.
Final Report 16 December 28, 2005

b. An additional primary data quality objective was to compare the lead loadings

before and after application of DCC/WG clearance protocols from the Second

Controlled Room study results (as referenced in Section 2.3.4) to the results from

this study. If they are found to be similar, results from the two studies could

complement each other and provide a stronger conclusion regarding efficacy of

the protocol(s).

c. A secondary data quality objective was to evaluate whether and how certain

covariates impact the results. Covariates of interest include the specific nature of

the protocol (e.g., whether dry DCC, wet DCC, or both), the initial dust-lead level

before application of the protocol, the surface area where the protocol was

applied, the type of surface material (e.g., hardwood, linoleum, painted concrete,

ceramic tile), and the condition of the surface (e.g., cleanliness, wear).

2. How does a DCC/WG clearance protocol “fail to achieve white glove” result compare

to a formal wipe clearance sample result?

a. Under certain conditions (e.g., caked on grease/grime or chipping paint), the

protocol did not always achieve white glove within the maximum number of

cloths permitted. For such cases encountered in this study, a separate estimate

was made of the probability that a wipe sample would result in a pass even when

the cleaning/clearance protocol fails to achieve a white glove condition. This

particular estimate was designated as a secondary data quality objective.

3.2 DCC/WG Clearance Protocol as Implemented in the Field Study

Figure 2 depicts the data collection protocol employed in this field study overlaid on the

envisioned implementation of a real-world protocol (as was illustrated in Figure 1). Those steps

in Figure 1 that are not included in the field study data collection protocol are indicated by

dashed connecting lines and the text boxes are cross-hatched with reverse color text (white on

dark). The additional steps in Figure 2 that do not apply to a real-world application, but were

needed to collect the data for this study, are shown as text boxes with gray (rather than white)

backgrounds. The 15 cloth limit shown in the lower right diamond of the figure is also grayed to

reflect the fact that this number was selected specifically for the field study. A different criteria

may well apply to an implemented real-world protocol. 

The implemented study, as shown in Figure 2, differed in some important ways from the

envisioned application of the protocol in real-world settings (see Figure 1). These differences

included:
Final Report 17 December 28, 2005

Figure 2. White Glove Clearance Testing Protocol for Field Study in Residential Housing
Final Report 18 December 28, 2005

• For the field study, two floors were selected at each field site that best met the desired

“smooth and cleanable” criteria that might apply to a real-world application of the

protocol. However, conditions at some sites were so poor that two adequately smooth

and cleanable surfaces were not available and the study had to settle with selecting

floors that came closest to meeting the desired criteria. In part, this was necessitated

by the supply of residential housing units where the study could be performed. 

However, it ultimately served the additional purpose of providing insight into what

might eventually constitute a definition of a surface that is not “smooth and

cleanable.” For instance, specific exclusionary floor (or sill) conditions might

include: large surface areas without finish, frequent and large cracks or crevices,

protuberances (e.g., staples, splinters), and a layer of accumulated grime/dirt.

• A thorough site cleanup (that typically would be conducted after R&R but before

clearance) was intentionally not included in the field testing protocol. Rather, a

perfunctory broom sweeping was conducted before any data collection commenced. 

The objective of only broom sweeping was to increase the chances of having lead

levels above the clearance standards before beginning the protocol. This permitted

evaluation of two important concerns about the DCC/WG clearance protocol; (1)

Would it ever achieve white glove when the surface lead levels exceed the clearance

standard? and (2) Can it successfully identify (by passing the white glove criteria) that

the lead loading was below the clearance standard when the DCCs are the vehicle

through which the lead reduction occurred? To get the results of this evaluation, the

DCCs were evaluated after a less intensive cleaning than might typically be done. In

the real world, a dirty DCC would demonstrate that primary cleaning had been

inadequate and this would trigger a complete recleaning effort for the entire room. 

For the field study, this was not the case. Regardless of how “dirty” the used cloth

was, a fresh DCC was instituted, up to an operational limit of 15 DCCs for floors and

3 for sills. This extended use of DCCs would be impractical and inefficient in actual

practice. 

• To quantitatively assess the efficacy of the protocol, an objective measurement was

needed for lead measurement before and after performance of the protocol. The

experimental design specifies that ASTM wipe samples be collected both before and

after DCC clearance testing. To minimize the inaccuracies introduced in measuring

overall floor lead loading with a 1 ft2 wipe sample, the experimental design provided

for two spatially separated samples on each floor surface at each time point. These

two measurements were averaged to determine the lead loading before and after

application of the protocol. For sills, a single pre and post-protocol wipe sample were

adequate because of the much smaller surface areas involved.
Final Report 19 December 28, 2005

3.3 Implemented Field Study

The implemented field study in residential housing comprised three important

components:

1. The locations - Locations were selected which might reasonably be expected to have

leaded dust from some renovation and remodeling work but primarily from lead

hazard control work . Additional information on the procedure for identification and

qualification of potential study locations is provided in Section 4.1, Site Selection.

2. The people - The field study protocol was generally performed by two sampling

technicians at each site. In Baltimore, the sampling technicians were employees of

Leadtec Services, Inc. or Healthy Housing Solutions, Inc. In Milwaukee, the

sampling technicians were staff of the Milwaukee Health Department. All

technicians were certified in clearance wipe sampling. The majority were

experienced lead risk assessors. Technicians followed the experimental protocol as

defined in the Quality Assurance Project Plan (see Appendix A). On-site training was

provided for all sampling technicians.

3. The protocol - A DCC/WG clearance protocol was performed on window sills and

floors at the residences with dust wipe clearance sampling before and after to

determine protocol efficacy.

A summarized and simplified version of the study protocol is as follows:

1. Identify two suitable rooms (designated Room A and Room B) within the housing

unit. In each chosen room, there should be evidence that lead hazard control, lead

abatement, or R&R-type work was completed, and that leaded dust might reasonably

be expected on the floors and window sills.

2. In each selected room, identify, measure, and, using masking tape, partition the floor

area into two approximately equal test areas. (The dry DCC and dry/wet DCC

protocol was tested in one area; the wet DCC protocol was tested in the other half.) 

3. Identify one window sill area in each room and partition this sill into two roughly

equal areas using masking tape.

4. In Room A, for the window sill:

a. Sweep any large debris from the sill.

b. Collect an ASTM wipe sample on one half of the sill.

c. Measure the associated dimensions of the sill to determine the area represented by

the wipe sample.
Final Report 20 December 28, 2005

d. Successively wipe dry DCCs over the other side of the sill until the used DCC

appears as clean as the reference white glove visual standard or until a maximum

number of DCCs (three) have been soiled.

e. Once achieving white glove (or the final limit cloth), perform a clearance wipe

sample on this same side of the sill, once again measuring the associated

dimensions of the sill.

5. In Room A, for the floor:

a. Sweep any large debris from the floor.

b. On one half of the floor

i. Randomly designate two, 1 ft2

 locations, and perform a clearance wipe sample

in each location.

ii. Perform the dry DCC/WG clearance protocol until a DCC mopped over the

entire floor surface is as clean as the appropriate visual standard for white

glove or until 15 cloths have been soiled without reaching this standard.

iii. Adjacent to the first two sampling locations, without overlapping any other

sample locations, take a second set of clearance wipe samples.

iv. Wipe the entire half floor surface with a single, wet DCC.

v. Adjacent to the first and second sets of samples, without overlapping any other

sample locations, take a final set of clearance wipe samples.

c. On the other half of the floor

i. Randomly designate two, 1 ft2 locations, and perform a clearance wipe sample

in each location.

ii. Perform the wet DCC/WG clearance protocol until a DCC mopped over the

entire floor surface is as clean as the appropriate visual standard for white

glove or until 15 cloths have been soiled without reaching this standard.

iii. Adjacent to the first two sampling locations, without overlapping any other

sample locations, take a second set of clearance wipe samples.

6. In Room B, for the window sill

a. Perform exactly the same protocol as for Room A, but use disposable wet cloths

instead of dry.

7. In Room B, for the floor

a. Perform exactly the same protocol as for Room A.

The critical sampling and cleaning cloth activities are illustrated in Figure 3. Floor

sampling is shown in the top diagram and sill sampling below. Each process diagram shows a

progressive view of the steps performed for each surface from initial wipe sampling, through

cloth mopping, and finally to post-protocol wipe sampling. At each step, the legend box under

each surface picture identifies the activity completed in that step. Activities previously

completed are retained on the diagram but are relegated to the background by graying or dashed

lines. In this way, the total protocol can be envisioned as a set of layers applied to a surface.
Final Report 21 December 28, 2005

Figure 3. Process Flow Diagram of Sampling for Residential Field Study

From the diagrams in Figure 3, it can be seen that the protocols can be evaluated for

effectiveness in the following manner:

For Floors

a. By comparing the mean of the two wipe samples taken after the dry protocol to the

mean of the two wipe samples before the dry protocol began, we can evaluate the

effectiveness of the Dry DCC/WG clearance protocol.

b. By comparing the mean of the two wipe samples after the dry protocol with one

additional wet DCC, to the mean of the two wipe samples before dry protocol began,
Final Report 22 December 28, 2005

we can evaluate the effectiveness of the Dry + 1 Wet DCC/WG clearance protocol.

c. By comparing the mean of the two wipe samples after the wet protocol to the mean of

the two wipe samples before the wet protocol began, we can evaluate the

effectiveness of the Wet DCC/WG clearance protocol.

For Sills

a. By comparing the value for the wipe sample taken after the dry protocol to the value

of the wipe sample before the dry protocol began, we can evaluate the effectiveness of

the Dry DCC/WG clearance protocol.

b. By comparing the value for the wipe sample taken after the wet protocol to the value

of the wipe sample before the wet protocol began, we can evaluate the effectiveness

of the Wet DCC/WG clearance protocol.

Note: No Dry + 1 Wet DCC/WG clearance protocol was evaluated for window sills

because the surface areas were insufficient to include this third treatment.

More specific details regarding selection of sampling locations, instructions for

performing the clearance wipe sampling, instructions for execution of the protocols (including

the appropriate visual standards), and required documentation of activities is provided in the

Quality Assurance Project Plan (see Appendix A).

3.4 QAPP Modifications

The following table details the deviations from the Quality Assurance Project Plan (see

Appendix A). For completeness, every known deviation has been included. However, it should

be noted that most of these deviations resulted from normal operational limitations that can be

expected in a field study of this type. The number and nature of the deviations were not judged

to threaten the accuracy or validity of the study results.

Sampling Unit Exception to QAPjP

Pilot (Unit 00) For Floor A, the condition of the half of the floor designated for the wet

treatment was deemed too poor to permit completion of the protocol.

Hence, pre-protocol wipe samples were taken but the protocol was not

completed, no post-protocol wipe samples were taken, and this half of the

floor surface was eliminated from the study.

01 For Floor B, the sampling staff ran out of time to do the half of the floor

surface slated to get the wet treatment, so this half of the floor surface was

eliminated from the study.
Sampling Unit Exception to QAPjP

Final Report 23 December 28, 2005

03 The two “halves” of Floor B are actually two very small adjacent rooms in

the unit. Additionally, in each of these spaces, the accumulation of

significant dried “mounds” or “caked-on” debris required more than just a

broom sweep before application of the protocol. In each case, debris was

first scraped from the floor surface before the broom sweep.

05 The sill with the wet treatment was recorded as failing to reach white glove

after two DCCs though this conclusion should not have been reached until

three DCCs had failed the visual inspection for white glove.

11 The wipe samples from this site were found to be mislabeled during

execution of the protocol. The measurements for this unit have been

excluded from the study results.

12 The sill with the wet treatment reached white glove in six DCCs, though

the treatment was supposed to be stopped and concluded as a white glove

failure after three DCCs failing the visual standard for white glove.

20 The sill with the wet treatment failed to reach white glove in six DCCs,

though the treatment was supposed to be stopped and concluded as a white

glove failure after three DCCs had failed the visual standard for white

glove. 

23 The sill with the dry treatment failed to reach white glove in six DCCs,

though the treatment was supposed to be stopped and concluded as a white

glove failure after three DCCs had failed the visual standard for white

glove.

25 The sill with the wet treatment failed to reach white glove in six DCCs,

though the treatment was supposed to be stopped and concluded as a white

glove failure after three DCCs had failed the visual standard for white

glove.

26 The sill with the wet treatment failed to reach white glove in six DCCs,

though the treatment was supposed to be stopped and concluded as a white

glove failure after three DCCs had failed the visual standard for white

glove.

27 The sill with the wet treatment reached white glove in six DCCs, though

the treatment was supposed to be stopped and concluded as a white glove

failure after three DCCs failing the visual standard for white glove.
Sampling Unit Exception to QAPjP

Final Report 24 December 28, 2005

28 No Floor A or Sill protocols were done in this unit. The Floor B protocol

consisted of the Wet Only treatment on both halves of the floor; one with

the mop manufacturer’s cleaning solution and one with only water as a

cleaning solution in the mop. Additionally, sampling where white glove

could not be achieved was limited to five cloths instead of the 15 required

in the QAPjP.

29 Floor A had the Dry+1Wet protocol applied to both halves of the floor.

The one wet cloth used the mop manufacturer’s cleaning solution on one

half of the floor. The one wet cloth on the other side of the floor used only

water as a cleaning solution in the mop. Floor B had the Wet Only

protocol applied to both halves of the floor. The mop manufacturer’s

cleaning solution was used on one half of the floor and only water was

used as a cleaning solution in the mop on the other half of the floor. The

side of the floor with only water failed to reach white glove in 14 DCCs,

though the protocol should have used 15 cloths before reaching that

conclusion.

30 Floor A had the Dry+1Wet protocol applied to both halves of the floor.

The one wet cloth used the mop manufacturer’s cleaning solution on one

half of the floor. The one wet cloth on the other side of the floor used only

water as a cleaning solution in the mop. Floor B had the Wet Only

protocol applied to both halves of the floor. The mop manufacturer’s

cleaning solution was used on one half of the floor and only water was

used as a cleaning solution in the mop on the other half of the floor.
Final Report 25 December 28, 2005

4.0 FIELD DATA COLLECTION

Field data collection was performed in Baltimore and Milwaukee from July to December

2004. A total of 31 housing units are included in the study results, 11 in Baltimore and 20 in

Milwaukee. The process for identifying and qualifying potential sample locations is explained in

Section 4.1. The locations, dates, and sample conditions for each unit are provided in Section

4.2.

4.1 Site Selection

The objective of the study was to identify real-world residential housing that could

provide an opportunity to assess the effectiveness of the protocol in determining if clearance had

been met. The selection of these units was restricted by the following factors:

• Units were obtained from owners willing to volunteer their property for the study.

Study team members in Baltimore worked through the City of Baltimore’s Lead

Program, as well as private owners, to identify units where the sampling team would

be allowed to complete the protocol. In Milwaukee, the City Lead Program was the

sampling team, though they still had to obtain permission from property owners to

perform the study. Though not strictly a requirement, it turned out to be logistically

easier to perform the protocol in uninhabited units. All sample units were

uninhabited at the time of sampling.

• It was desired to include as many units as possible with expected, pre-protocol lead

levels above the clearance standard for reasons explained in Section 3.2. In

Baltimore, selection of units with expected lead hazards was done subjectively, which

resulted in some units that were sampled having very low lead contamination levels. 

In Milwaukee, risk assessment sampling was used to identify and qualify units with

floors over the clearance standard.

• Some surface conditions were known in advance of this study to be untenable with

the proposed experimental protocol; therefore, these conditions were used to screen

potential sample locations. To the extent possible, surfaces were required to be

“smooth and cleanable.” While this terminology could be interpreted in different

ways, it was used in this study to exclude any surfaces that were in very poor

condition (e.g., cracking, splintering) so that the protocol could not be reasonably

implemented, because the DCCs would catch or tear apart on the surface

imperfections. As discussed in Section 3.2, this still resulted in some testing for the

field study of surfaces that would probably not meet “smooth and cleanable”

standards applicable to a general use of the protocol. Additionally, only hard surfaces

were considered (e.g., no carpeting). Other factors of floor condition were considered

in this study and are discussed in more detail in Section 6.3.
Final Report 26 December 28, 2005

4.2 Sampling Locations and Conditions

Tables 1 and 2 show detailed descriptions of the 31 units sampled. In addition to the

location and date, each table shows the size of the surface area, the surface material, the surface

condition, and what treatments were applied.

The floor areas in this evaluation ranged from 48 to 225 ft2

. Since two separate treatments

were completed on each floor (combined dry and dry+1wet or wet only), the results reported for

this study represent floor areas ranging from approximately 24 to 113 ft2. The majority of floor

surfaces sampled were wood (72 %). An additional 26% were linoleum or tile. In one location,

concrete floors were sampled. Surface conditions varied from very good (newly installed or

refinished wood floors with a polyurethane seal) to very poor (rough surfaces, unfinished

surfaces, cracked). Appendix G contains a gallery of digital photographs of the floor surfaces

sampled. In this appendix, Floor A for Unit 01 is an example of a floor in good condition. and

Floor A for Unit 03 is an example of a floor in poor condition.

The protocol was applied to sill surfaces ranging from 0.4 to 2.4 ft2. Two sill surfaces

were identified as ‘painted’ without designation to their underlying surface material. Otherwise,

all other sills were recorded to be wood. Sill surface conditions varied over the same range as

floor conditions.

The Swiffer® and Swiffer® Wet® cloths were used for all dry DCC and wet DCC

sampling, respectively, on window sills. For floors, the dry treatment was completed with the

Swiffer® mop and corresponding dry, electrostatic cloths at all locations. The wet treatment (and

the +1 wet cloth after the dry treatment) used two different systems; the Swiffer® WetJet® and

the Clorox® ReadyMop®. These are commercially available mop handles with an attachment for

a bottle of cleaning solution. Dry disposable cleaning pads are affixed to the rectangular mop

head and a trigger on the mop sprays a stream of cleaning solution ahead of the mop head onto

the floor. The spray function is battery-operated for the Swiffer® product and manual for the

Clorox® product. 

For Units 28-30, the treatments utilizing wet DCCs were modified slightly to obtain a

comparison of the protocol effectiveness with the manufacturer’s cleaning solution to

performance with only water as the cleaning solution. The results of this analysis are shown in

Section 6.2.3.4.
Final Report 27 December 28, 2005

Table 1. Field Study Floor Sampling
Final Report 28 December 28, 2005

Table 2. Field Study Sill Sampling
Final Report 29 December 28, 2005

5.0 LABORATORY ANALYSIS

All ASTM wipe sample preparation and analysis was conducted by Microbac

Laboratories, Inc., Gascoyne Division, an NLLAP-accredited laboratory. Details of the applicable

analytical methods are provided in Section 5.1. Descriptions of the laboratory QC results are

provided in Section 5.2.

5.1 Review of Analytical Methods

Sample analysis was conducted using Flame Atomic Absorption Spectrophotometry in

accordance with NIOSH method 7082. This method provided accurate measurement of lead

content to a lower quantitation limit of 10 :g per wipe sample.

All digestates from samples were stored following analysis in the event that EPA should

desire a re-analysis of the samples (e.g., with an analytical method providing a lower quantitation

limit).

5.2 Laboratory QC Results

QC samples for this study included the following:

Field Blanks - Field sampling staff inserted a single blank wipe into an empty sample

collection tube at the conclusion of sampling activities at each unit and returned that sample with

the other wipe samples. This sample was analyzed by the laboratory with the expectation that the

result would show no lead contamination.

Table 3 shows that all field blanks with the exception of one were below the quantitation

limit. The one exception was for Unit 08 which showed a measurement of 15 :g. This sample

was re-analyzed in the lab with a similar result (17 :g). Review of the sample log yielded no

explanation for why the field blank might have had lead contamination. Consequently, the data

for Unit 08 have been left in the final statistical analysis.

Spiked Samples - To provide a check on the analytical laboratory, Battelle laboratory staff

prepared two spiked wipe samples for analysis with other sampling data in each unit. One wipe

was spiked at 20 micrograms of lead and the second at 40 micrograms. Table 4 shows the

Microbac laboratory analytical results for these spiked samples.
Final Report 30 December 28, 2005

Table 3. Field Blank Sample Results
2NIST certified 9761 mg/kg with 95 percent prediction interval of ± 67 mg/kg for samples

of at least 100 mg.

Final Report 31 December 28, 2005

Table 4. Sampling Results from Battelle Laboratory Spike QC Samples

In 9 of the 62 samples (highlighted in gray), the measured recovery was outside the

QAPjP requirement of +/- 20% of the target values. These samples exhibit greater variability

than expected in the spiked sample recoveries. Additionally, the average measured recovery was

90.5 percent for the 20 microgram samples and 90.8 percent for the 40 microgram samples. This

suggests also a potential bias in sample recoveries. However, the small amounts of SRM 2584

(nominal 1% lead2

 by weight) required to produce the 20 and 40 microgram samples (two and

four milligrams, respectively) fall well below the minimum 100 mg sample size at which NIST
Final Report 32 December 28, 2005

has specified a known uncertainty of the mass fraction of lead in the SRM. Therefore, it could

well be that the failures and bias result from variation (about one percent) in the true mass

fraction of lead used to spike the samples.

If the observed bias is reflective of the laboratory lead measurement (and not a bias in

preparation of the spiked samples), it may indicate that the measured results from the wipe

samples in the study are artificially low. To understand the impact of this possibility, the study

results were adjusted under the assumption that laboratory measured lead levels were only 90

percent of the true lead levels. These recalculated results were not different for the primary data

quality objective of assessing whether attaining white glove was reflective of meeting the

clearance standard. The recalculated results did show minor changes for other study results. 

Laboratory QC Samples - As part of its standard laboratory QC procedures, Microbac

Laboratories performed QC samples including independent calibration verifications, independent

calibration blanks, continuing calibration verifications and blanks, post-digest analytical spikes

and duplicates, and sample wipe laboratory blanks. These were collected consistent with the

requirements of Table 2-2 in Section 2.4 of the QAPjP (see Appendix A). They are summarized

in Table 5 below.

Review of the QC data did not identify any deviations from the required frequency or

acceptance limits for these samples.

Table 5. Analytical Laboratory QC Sample Results 
Final Report 33 December 28, 2005

6.0 ANALYSIS RESULTS

This section provides graphical and tabular summaries of the data obtained from the field

study as well as detailed discussion of findings with regard to each of the study data quality

objectives (as introduced in Section 3.1). Section 6.1 provides reference graphs and tables of the

field study data. Section 6.2 contains a detailed discussion of the results by quality objective.

6.1 Graphical and Tabular Summaries of Results

Five separate treatments were evaluated in the field study. These included:

– For Floors

Dry Cloth to White Glove (or a maximum limit of 15 DCCs) - Graph 1

Dry Cloth to White Glove (or a maximum limit of 15 DCCs) Followed by One Wet Cloth 

- Graph 2

Wet Cloth to White Glove (or a maximum limit of 15 DCCs) - Graph 3

– For Window Sills 

Dry Cloth to White Glove (or a maximum limit of 3 DCCs) - Graph 4

Wet Cloth to White Glove (or a maximum limit of 3 DCCs) - Graph 5

Each of the scatter plots for these five treatments display the relationship between the

lead loading on each test floor or window surface before the protocol was begun and the lead

loading after completion of the clearance protocol. Note that for each floor test surface, two wipe

samples were collected before and after conducting each treatment protocol. (The before and

after wipe samples were collected side by side to minimize spatial variability.) The measurement

results used in each scatter plot graph are the arithmetic means of the paired wipe sample

measurements. For the window sill surfaces, only a single pre-protocol and post-protocol wipe

sample were taken due to sill size limitations. Both the horizontal and vertical axes are a

logarithmic scale.

Each graph includes two types of points. The empty boxes represent the data points

where the clearance protocol achieved white glove. The pluses are the data points where the

protocol failed to achieve white glove. Measured lead loadings less than the laboratory’s

minimum quantitation limit of 10 :g/ft2 are represented as one half this limit (i.e., 5 :g/ft2).
Final Report 34 December 28, 2005

Finally, each graph shows dotted reference lines (both horizontally and vertically) at the

clearance standard (40 micrograms for floors, 250 micrograms for sills). Using these lines, the

graphs are separated into four quadrants with the following labels and definitions:

a. Points plotted in the upper left hand quadrant represent surfaces that were below the

clearance standard before the DCC/WG protocol and ended up above the clearance

standard afterward.

b. Points plotted in the upper right hand quadrant represent surfaces that were above

the clearance standard before the DCC/WG protocol and remained above the

clearance standard afterward.

c. Points plotted in the lower left hand quadrant represent surfaces that were below the

clearance standard before the DCC/WG protocol and remained below the clearance

standard afterward.

d. Points plotted in the lower right hand quadrant represent surfaces that were above

the clearance standard before the DCC/WG protocol and fell below the clearance

standard afterward.

Graph 1 - Dry Cloth to White Glove (or Max 15 Cloths) on Floors
Final Report 35 December 28, 2005

Graph 2 - Dry Cloth to White Glove (or Max 15 Cloths)

Followed by One Wet Cloth on Floors

Graph 3 - Wet Cloth to White Glove (or Max 15 Cloths) on Floors
Final Report 36 December 28, 2005

Graph 4 - Dry Cloth to White Glove (or Max 3 Cloths) on Sills

Graph 5 - Wet Cloth to White Glove (or Max 3 Cloths) on Sills
Final Report 37 December 28, 2005

Table 6 provides counts of surfaces over or under the clearance standard after completing

each of the five treatments. The counts are grouped by whether or not white glove was achieved

and whether the surface was initially above or below the clearance standard before performance

of the protocol. In this way, Table 6 essentially provides two cross tabulations (achieving white

glove or not achieving white glove) of numbers of data points in each of the four quadrants of

Graphs 1-5.

Table 6. Counts of Surfaces Over or Under Clearance Standards by Treatment, PreProtocol Lead Loading, and White Glove Status
Final Report 38 December 28, 2005

Table 7 presents an overall summary of the effectiveness of each treatment. For surfaces

achieving white glove, the number of surfaces sampled and the number below the standard after

performance of the protocol are shown. From these two quantities, the estimated protocol success

rate is calculated as:

This is an estimate of the probability that the lead level of the surface will be below the clearance

standard given that the white glove condition was met. If the number of surfaces Below Standard

After Protocol is designated as s and the number of Total Surfaces as n, an estimated lower 95%

confidence bound on the protocol success rate is:

This p signifies the true population success rate below which it would be unusual (i.e., less than

or equal to 5% chance) to observe as many or more successes as were observed in this study.

For surfaces that failed to achieve white glove, Table 7 shows the total number of

surfaces, the number below the standard after the protocol, and the percentage that met the 

clearance standard (despite failing to achieve white glove).

Table 7. Overall DCC/WG Clearance Protocol Success Rates by Treatment
Final Report 39 December 28, 2005

6.2 Results by Data Quality Objective

6.2.1 Data Quality Objective 1

The first data quality objective of this study was to estimate the probability (and

corresponding one-sided 95% lower confidence bound) that surfaces will achieve the appropriate

clearance standard (as determined by wipe sampling), given that the floor or window sill surfaces

have passed the white glove test using the DCC/WG clearance protocol. Table 7 provides these

estimates for each of the protocol variations examined on floors and sills.

In Table 7, each of the five treatments is listed in a separate row, identified by the surface

type (floor or sill), corresponding clearance standard, and specific variation of the protocol tested

(wet, dry, or a combination). Data Quality Objective 1 is concerned with the portion of the table

for ‘Surfaces Achieving White Glove.’ Further discussion is provided for each of the five

treatments in Sections 6.2.1.1 through 6.2.1.5. 

6.2.1.1 Data Quality Objective 1 - Dry Cloth to White Glove Treatment on Floors. 

The first row of Table 7 shows that 47 floor surfaces out of a total of 58 treated floors achieved

white glove with the dry cloth treatment. In 43 of these 47 cases, the post-treatment protocol

mean wipe sample results were at 40 :g/ft2 or less. This results in an estimated 91.5% success

rate. The lower bound for a one-sided 95% confidence interval for this estimate is an 81.6%

success rate. Hence, the results from this study provide strong evidence (i.e., 95% confidence)

that the protocol would be effective in similar housing at least 81.6% of the time. The results for

this treatment were shown in Graph 1.

Further examination of the dry protocol results is provided under Data Quality Objective

2 (Section 6.2.2).

6.2.1.2 Data Quality Objective 1 - Dry Cloth to White Glove + 1 Wet Cloth

Treatment on Floors. For each of the 47 surfaces that achieved white glove with the dry cloth

treatment, a single additional clearance wiping was performed with a wet cloth. Only 38 of these

47 surfaces (second row of Table 7) showed mean wipe sample results of 40 :g/ft2 or less after

the additional wet cloth. This corresponds to an estimated 80.9% success rate. The lower bound

for a one-sided 95% confidence interval for this estimate is 69.0%. Hence, the results from this

study provide strong evidence (i.e., 95% confidence) that the protocol would be effective in

similar housing at least 69.0% of the time. The results for this treatment were shown in Graph 2.

The poorer estimated success rate for this treatment (80.9%) as compared to the dry cloth

treatment alone (91.5%) was unexpected. Laboratory data collected on smooth vinyl tile floors

had shown that a protocol that included a wet cloth mopping after reaching white glove with dry

cloths was more effective at reducing lead levels than the dry cloth treatment alone. While the

result from this study is not explained, one hypothesis is that the single wet cloth loosens and

disburses significant lead from cracks or crevices that subsequently become available to a wipe

sample collection but which would not have been accessible after a dry cloth treatment alone.
Final Report 40 December 28, 2005

Also, it should be noted that though the dry cloth treatment alone has a higher estimated

effectiveness than the combined dry and wet cloth treatment, the difference observed in this study

is not statistically significant.

6.2.1.3 Data Quality Objective 1 - Wet Cloth to White Glove Treatment on Floors.

The wet only DCC/WG clearance protocol performed best of the three DCC protocols tested on

floors (third row of Table 7 and Graph 3). The wet cloth protocol passed clearance for 36 of 37

surfaces where white glove was achieved, corresponding to a 97.3% success rate. The lower

bound for a one-sided 95% confidence interval for this estimate is 87.8%. Hence, the results

from this study provide strong evidence (i.e., 95% confidence) that the protocol would be

effective in similar housing at least 87.8% of the time. Although higher than the results for either

the Dry or Dry+1 Wet treatments, the observed success rate for the wet protocol was not

statistically significantly better than either of the other two.

Though not statistically significant, the order of observed effectiveness (dry+1 wet, dry

only, wet only), if true, is still puzzling: Why would one wet cloth not improve on the dry result

but multiple wet cloths would have the best observed performance? A possible explanation for

the poorer performance of the dry+1 wet cloth treatment compared to the dry cloth only treatment

was presented in 6.2.1.2 above. The logical extension to this hypothesis is that the additional

leaded dust exposed by the wet cloth cannot be adequately removed with only one wet cloth. 

However, multiple wet cloths will eventually remove it and ultimately leave even less available

leaded dust for a dust wipe sample than a protocol based on dry DCCs.

6.2.1.4 Data Quality Objective 1 - Dry Cloth to White Glove Treatment on Sills. The

fourth row of Table 7 shows that 27 of 28 (96.4%) sills receiving the dry cloth to white glove

treatment where white glove was achieved were found to be below the clearance standard of 250

:g/ft2. This corresponds to a lower 95% confidence bound of 84.2% on the protocol success rate. 

One important factor with the sill results (as seen in Graph 4 and on Table 6) is that only a small

number of sills that reached white glove with this treatment (six sills) were initially above the

clearance standard before application of the treatment. Also, the surface of the single window sill

that failed clearance was one of those initially above the clearance standard and that it was in

especially poor condition with deterioration to the paint and underlying wood.

6.2.1.5 Data Quality Objective 1 - Wet Cloth to White Glove Treatment on Sills. The

fifth row of Table 7 shows that 25 of 25 (100%) sills receiving the wet cloth to white glove

treatment where white glove was achieved were found to be below the clearance standard of 250

:g/ft2. This corresponds to a lower 95% confidence bound on the protocol success rate of at least

88.7%. As with the dry cloth protocol, only a small number of sills that reached white glove with

this treatment (seven sills) were initially above the clearance standard before application of the

treatment (as seen in Graph 5 and on Table 6). 
Final Report 41 December 28, 2005

6.2.2 Data Quality Objective 2

One objective of this field study was to compare the results obtained with those of the

Second Controlled Room Study (see Appendix E). In the Second Controlled Room Study, the

effectiveness of the DCC/WG clearance protocol was examined on a single floor surface and

with predetermined lead contamination levels. The planned nature of this previous study is the

source of the ‘controlled room’ name. It is titled the ‘second’ controlled room study because an

earlier controlled room evaluation was performed (see Appendix C). For simplicity, future

references in Section 6.2.2 to the Second Controlled Room Study will refer to it as the controlled

room study.

The experimental design for the controlled room study involved spiking a vinyl tile floor

(48 ft2 test areas) with one of two lead-containing standard reference materials (SRM #2584 =

house dust with 1% lead, SRM #2589 = pulverized paint with 10% lead). For each test area,

carefully measured quantities of the SRM were uniformly dispersed over the entire 48 ft2

 area at

one of four different lead loadings: 40 :g/ft2, 200 :g/ft2, 600 :g/ft2, and 1600 :g/ft2. Each of the

two SRM/lead concentrations and four lead loading combinations was repeated three times for a

total of 24 floor areas tested (2 x 4 x 3 = 24). A DCC/WG clearance protocol (similar to the dry

cloth treatment used in the field study) was executed for each floor test area and was followed by

collection of four clearance wipe samples from each floor test area. By comparing the wipe

sample results collected after the protocol with the known (initial) lead spiking levels, the

effectiveness of the treatment was evaluated for each lead loading/lead concentration

combination.

6.2.2.1 Comparison of Dry DCC/WG Treatment Between Controlled Room and

Field Study. The following sections separately outline the results for the dry DCC/WG

treatment in the controlled room study (Section 6.2.2.1.1), the field study (Section 6.2.2.1.2), and

then the comparison of the two results (Section 6.2.2.1.3).

6.2.2.1.1 Dry Cloth to White Glove in Second Controlled Room Study. Graph 6 displays

the comparison of the means of post-protocol lead loadings to initial lead loadings for the dry

DCC mopping protocol executed in the Second Controlled Room Study in late 2003. As

described above, each floor surface was spiked with a carefully measured mass of lead

(approximately 40, 200, 600, or 1,600 :g/ft2) in one of two different concentrations (1% and 10%

by weight).
Final Report 42 December 28, 2005

Graph 6 - Dry Cleaning Cloth to White Glove on Floors - Second Controlled Room Study (2003)

Graph 6 shows a linear regression model fit of the post-protocol lead levels versus the

initial lead loading (after log-transforming both measures). The model shows a moderately

strong linear relationship (r2

 = 0.83) between the dependent (post-protocol lead loading) and

independent (initial lead loading) variables. Though depicted individually, there was not a

statistically significant difference in relationship between the 1% and 10% SRM concentrations.

Graph 6 also shows an upper 95% confidence interval for a single predicted value. It is

this upper prediction interval that is of particular interest, especially at the point where it

intersects the horizontal reference line (40 :g/ft2

) for the clearance standard. The intersection

point in Graph 6 falls at approximately 385 :g/ft2

. This mean that we are 95% confident that a

floor with an initial (pre-treatment) lead loading of 385 :g/ft2

 or less would pass clearance based

on the data from the controlled room study.
Final Report 43 December 28, 2005

6.2.2.1.2 Dry Cloth to White Glove in Field Study in Residential Housing. Graph 7

displays the relationship of the means for post-protocol to initial lead loadings for the dry cloth

DCC/WG protocol from the current field study in residential homes. These data are the same as

plotted in Graph 2 except that the data points for the floor surfaces that did not achieve white

glove are excluded because they are not relevant to this assessment of protocol success. The

point where the upper 95% prediction interval for Graph 7 intersects the clearance standard line

falls at approximately 45 :g/ft2

.

Graph 7 - Dry Cleaning Cloth to White Glove on Floors -

Field Study in Residential Housing (2004)

It should be noted that the linear regression model fit (and accompanying upper 95%

prediction interval) have two important limitations as compared to the model for the controlled

room study: (1) the assumption of equal variance about the regression fit line seems much less

reasonable than it does for Graph 6, and (2) there are many censored values in this data set (also

relates to the first limitation). Hence, while a regression line has been fit through the data, it

should be interpreted cautiously.
Final Report 44 December 28, 2005

6.2.2.1.3 Comparison of Second Controlled Room Study and Field Study in Residential

Housing - Dry Cloth to White Glove. The intersection point for the upper 95% prediction

interval with the 40 :g/ft2 clearance standard reference line is lower in the field study (45 :g/ft2)

than in the controlled room study (385 :g/ft2

). The interpretation of this finding is that the

controlled room study suggests the possibility of ultimately achieving a passing clearance level

with the DCC/WG clearance protocols when starting from a much higher initial lead loading than

what appears achievable based on the field study results.

Although the true reasons for the difference in the prediction intervals between the two

studies are not known, some observations may clarify the situation. The research staff involved

in both studies noted that the field study involved a more complex lead-contamination scenario

than in the controlled room. The controlled room study involved ‘spiking’ with leaded dust

‘sprinkled uniformly’ onto the floor surfaces, which were then misted with water and left to dry. 

The objective of misting with water was to develop some adhesion between the floor surface and

the lead dust. It is conjectured that a relatively high proportion of this recently deposited (and

water misted) lead dust was easy to remove with a dry DCC. 

By comparison, in some of the real-world sites of the field study, lead dust adhered to

floors far more strongly than in the controlled room. Leaded dust had probably been

accumulating on floors over a long time and may have been mixed with sticky substances such as

wax and grease. Under these condition, the result was a much stronger adhesion of lead to the

floor surfaces. A floor with caked-on, dried grime presents special problems for the dry cloth

treatment. The dry cloths reach a point where no additional free dirt or debris are collected (i.e.,

white glove is achieved) but the ground-in dirt or dried residue still retains lead that can be

dissolved by moist clearance wipe sample cloths. Clear adhesion of lead-containing grime to

surfaces can be a critical issue in real-world situations.

Another critical factor is the condition of the floors (and window sills). In the controlled

room study, the vinyl tile floor was in excellent condition with no observable cracks or crevices. 

Many of the field study floors exhibited considerable damage and deterioration. Floors with

exposed wood grain, disintegrating wood, or with frequent cracks and crevices are problematic

for cleaning and sampling. They tend to capture and retain lead dust even after cleanup. So, the

factors of floor condition, lead-dust contamination and the interaction of the two may account for

the difference observed between the two studies in the apparent efficacy of the dry cloth

treatment. 

In the final analysis, Graph 6 and Graph 7 clearly show that dry cloth treatment

performance was far better in the controlled room than for the field study. The controlled room

study employed a clean vinyl floor that was in good condition. Lead-containing materials (SRM

2584 and 2589) were recently applied. The adhesion and entrapment of lead particles that

inevitably occurs in the real-world sites was not a serious issue in the controlled room study. As

such, the controlled room study may be viewed as a near-best-case scenario demonstrating how

well the dry DCC/WG clearance protocol might be expected to perform under ideal conditions. 
Final Report 45 December 28, 2005

6.2.2.2 Comparison of Dry+1 Wet DCC/WG Treatment Between Controlled Room

and Field Study. As in the current field study, the controlled room study also examined

variations on the DCC/WG clearance protocol. The controlled room study included some trials

with a single wet DCC after the dry DCC/WG treatment had been completed. This protocol

variation was performed on nine floors for a lead loading level of 1600 :g/ft2

. Graph 8 is a

duplicate of Graph 6 except that it includes these additional data points with a wet DCC. They

are identified as the filled-in data points and are all at an initial lead loading of approximately

1600 :g/ft2.

Graph 8 - Dry DCC/WG and Dry + 1 Wet DCC/WG Treatments on Floors - 

Second Controlled Room Study (2003)

From Graph 8 it can be seen that the inclusion of a single wet DCC after the dry

DCC/WG clearance protocol produced a reduction in the mean lead loading compared to the

comparable points with only the dry DCC/WG treatment. Floors starting at 1600 :g/ft2 lead

contamination and treated with the dry DCC/WG clearance protocol reached a mean posttreatment lead level of 49.1 :g/ft2

 (standard deviation=17.3). Adding one additional wet DCC

mopping to floors contaminated at the same initial level resulted in a post-treatment level

averaging 16.0 :g/ft2 (standard deviation=5.6). (Note that the dry+1 wet treatment points are

offset slightly to the right in Graph 8 so they can be clearly distinguished from the dry treatment

only points. Both sets of points are at very nearly 1600 :g/ft2

 lead loading before performance of

their respective DCC/WG clearance protocols.)
Final Report 46 December 28, 2005

As was discussed in 6.2.1.2, the application of the dry cloth + 1 wet cloth DCC/WG

clearance protocol in the field study did not produce a statistically significant improvement over

the treatment with the dry DCC alone. The controlled room study did seem to show better

protocol performance with the addition of a wet DCC. Within the context of the previous

discussion, the apparent contradiction in the two study results may be explainable. For the

controlled room study where (1) floor conditions were very good, (2) the application of the

leaded material was recent, and (3) attempts to produce adhesion were minor, the addition of a

single wet DCC was sufficient to significantly improve lead reduction relative to a dry DCC/WG

treatment alone. In the field study with many floors in poor condition and firmly adhered leaded

matter, a single wet DCC was not sufficient to improve lead reduction relative to the dry

DCC/WG treatment alone. However, multiple wet DCCs in the field study could eventually

break down and remove the more embedded leaded material.

6.2.3 Data Quality Objective 3

A number of covariate factors relating to the performance (success or failure) of the

DCC/WG clearance protocols were examined. The primary focus of this analysis was the

scenario of meeting the clearance standard when white glove is achieved. Covariates that were

examined included the specific DCC/WG clearance protocol performed (Section 6.2.3.1), the

pre-treatment lead contamination level (Section 6.2.3.2), and other covariates (Section 6.2.3.3).

Additionally, this field study incorporated an evaluation of whether the specific cleaning solution

used had an impact on the performance results (Section 6.2.3.4).

6.2.3.1 Performance of DCC/WG Clearance Protocol by Treatment Type. The

results for each DCC/WG clearance protocol on floors and sills was discussed under Data

Quality Objective 1 (Section 6.2.1). 

• The observed performance of the wet treatment on floors (97.3%) was greater than

that of the dry treatment (91.5%) which in turn was greater than that of the dry + 1

wet treatment (80.9%). However, the comparisons of each pair of treatments in this

set using Fisher’s exact test shows that none of the differences are statistically

significant when the joint confidence level for the three pairwise comparisons is

95%. Hence, there is not sufficient evidence to conclude that the true performance

of any of the three DCC/WG treatments on floors are different from each other.

However, it should be noted that the small sample sizes limit the likelihood of

identifying a sample difference as statistically significant unless the true population

difference is fairly large. This study showed approximate 80% power (probability of

concluding a difference when one actually does exist) when one treatment’s

performance was 95% and either of the comparison treatments was at least 30%

poorer.
Final Report 47 December 28, 2005

• The observed performance of the wet treatment on sills (100%) was greater than

that of the dry treatment (96.4%). However, comparison of these two treatments

with Fisher’s exact test shows that the difference between them is not statistically

significant with 95% confidence. The small sample size affects this comparison just

as for the floor treatments. The statistical comparison of sill performance by

treatment has approximate 80% power when one treatment’s performance is 95%

and the comparison treatment is at least 30% poorer.

6.2.3.2 Performance of DCC/WG Clearance Protocol by Pre-treatment

Contamination Level. For the dry treatment results on floors (see Graph 1), there does appear

to be a relationship between pre-protocol contamination levels and final lead loading achieved

upon reaching white glove. This relationship is most apparent when initial lead loading levels

exceed about 20 :g/ft2. (Because of the heavy censoring effect of the method detection limit in

this study, it is not possible to examine this relationship at lower initial lead loading levels.) 

Generally, floors initially contaminated at higher lead levels were observed to have higher final

lead loadings after reaching white glove. However, there is considerable variability about this

relationship. As discussed earlier, it is believed that the success or failure of the dry treatment at

higher initial lead loadings lies in whether the lead content is contained in loose dust or whether

the lead is somehow bound to the floor surface. If lead is contained only in loose dust, the dry

treatment can achieve white glove and reduce lead loadings to levels equivalent to that of a floor

with lower initial lead levels (though, of course, it may require more dry DCCs to do so). 

However, if the lead is tightly bound to the floor surface, the dry protocol can be susceptible to

attaining white glove when no further leaded material can be picked up by this protocol even

though there are higher remaining levels of lead that could be collected (as with a wet clearance

wipe).

For the dry + 1 wet treatment results on floors (see Graph 2), the conclusions appear very

similar to the dry treatment alone.

Unlike the treatments with the dry DCCs, the wet DCC/WG clearance protocol results on

floors appear equally effective across the entire range of initial lead concentrations encountered

for this field study (average of side-by-side measurements ranging from less than 10 :g/ft2

 to a

maximum of 375 :g/ft2). This can be seen in Graph 3. Of course, because of the heavy

censoring effect of the quantitation limit, it is possible that some trend exists below 10 :g/ft2. 

Regardless, the result is still clear that across a wide range of initial contamination levels, the wet

treatment consistently and substantially reduced lead levels to well below the clearance standard. 

For both the dry (see Graph 4) and wet (see Graph 5) treatment results on sills, there is no

obviously visible relationship between measured lead level after the DCC/WG clearance protocol

compared to before the protocol. For both treatments, the range of initial lead loadings on sills

extended from less than 10 :g/ft2 to more than 2,000 :g/ft2. Therefore, it does not appear within

this range of initial lead loadings that the pre-protocol contamination level had a significant

effect on the lead loading attained after the protocol. 
Final Report 48 December 28, 2005

6.2.3.3 Performance of DCC/WG Clearance Protocol as a Function of Other

Covariates. The primary statistical results from this study are presented for each treatment as

the proportion of surfaces achieving white glove that were found to have residual lead

contamination below the clearance standard. It would be desirable to ascertain whether the

observed results can be associated with additional covariates encountered in the field study such

as: (1) size of surface treated, (2) type of surface material, and (3) initial condition of the surface. 

The small sample size for this study and the form of the performance estimates (i.e., proportions)

preclude a robust statistical evaluation of the effects of these covariates. However, Table 8

provides a summary of the characteristics of the surfaces that failed (i.e., reached white glove but

were not below the clearance standard) and compares these to all surfaces tested in the field

study. 

Table 8. Covariate Levels for DCC/WG Clearance Protocol Failures Compared to All

Surfaces

From the summary results in Table 8, the average treated surface areas, distribution of

surface material types, and average initial surface condition codes are similar between the

surfaces that failed to meet the clearance standard (after reaching white glove) and the entire

sample of surfaces in the field study. One possible exception is the sill that did not meet

clearance after reaching white glove. The surface condition code for this sill is poorer (at 4) than

most other sills encountered in the study (average of 1.9).
Final Report 49 December 28, 2005

Additional anecdotal observation of covariate results included:

• Wood floor surfaces that were not finished and sealed (e.g., with polyurethane) did

not fair poorly in reduction of lead but they did present difficulties in achieving white

glove.

• Floors with cracks, splintering, or protuberances (dried spackle, staples) made it

operationally difficult to perform the protocol because the DCCs would tear on the

imperfections. Interestingly, though, despite the fact that the protocol could not be

recommended from an operational standpoint on these surfaces, the reduction of lead

levels was often just as successful here as on smoother surfaces.

6.2.3.4 Performance of Wet DCC/WG Clearance Protocol as a Function of Cleaning

Fluid Used. A question raised in the development of the study plan was whether the results

observed for the wet treatment would be applicable only for the specific cleaning fluid used with

the DCCs. This issue is important because it ultimately bears on how a final recommendation is

made for which wet DCC products are acceptable. To examine this study question, two different

mopping products were evaluated. Additionally, for a small number of floors, a change was

made to the experimental protocol on floor surfaces to evaluate the effects of using plain tap

water as the cleaning fluid rather than the mop manufacturer’s own detergent. Table 9 shows the

relevant results from this evaluation.

Table 9. Comparison of Wet DCC/WG Clearance Protocol Performance with Two

Commercially Available Cleaning Solutions and Water

Unit - Mop Used

First Half of Room Second Half of Room

Cleaning

Solution

Lead Loading

(:g/ft2)

Cleaning

Solution

Lead Loading

(:g/ft2)

PreProto

col

PostProto

col

PreProto

col

PostProto

col

28 - Swiffer® WetJet® Swiffer 42 <10 Water 50 <10

41 16 63 11

29 - Clorox® ReadyMop® Clorox 47 16 Water 16 17

40 9 18 14

30 - Swiffer® WetJet® Swiffer 81 <10 Water 61 <10

80 <10 62 <10

 
Final Report 50 December 28, 2005

The results obtained appear repeatable whether using the two commercial cleaning

solutions or water. If true, this may imply that it is not actually the specific formula of the

detergent that is important in achieving success with the wet DCC/WG clearance protocol but the

fact that a liquid is used at all. However, the very small sample size of this evaluation precludes

coming to a definitive conclusion on this issue and further study is recommended.

Note that due to the comparability of results for the different cleaning solutions (as well

as water), results presented elsewhere for the wet DCC/WG clearance protocol in this study are

made without distinction as to which cleaning solution was used.

6.2.4 Data Quality Objective 4

Data Quality Objective 4 was created to examine those cases where a DCC/WG clearance

protocol was completed but white glove was not achieved. It was asserted that a beneficial

concept of the white glove test would be that it recognized its own limits. That is, if the protocol

failed to achieve white glove, it would be an indication that the clearance standard had not been

met and that a more thorough cleaning or surface refinishing was necessary.

Table 7 (presented in Section 6.1) showed, by treatment, the proportion of surfaces that

had measured lead levels below the clearance standard even though white glove was not

achieved. The results are surprisingly similar to the performance of the treatments when white

glove was achieved. With Fisher’s exact test, none of the five treatments exhibited a statistically

significant difference in performance between the surfaces that reached white glove and those

that did not. Therefore, we cannot conclude that whether a treatment reached white glove in this

field study impacted the final effectiveness of the treatment in reducing the surface lead loadings

to below the clearance standard. However, it should be noted that the small sample sizes

involved in these comparisons do not preclude the possibility that some true (and possibly large)

differences do exist. 

Table 10 provides summary statistics on the average and standard deviation of the

number of DCCs required to reach white glove for each treatment as well as the corresponding

average and variability in number of DCCs when white glove was not achieved.
Final Report 51 December 28, 2005

Table 10. Average Numbers of DCCs Used

Those surfaces that did not meet white glove had on average about twice the number of

DCC moppings used as surfaces where white glove was achieved. It is possible that the surfaces

not meeting white glove achieved comparable performance to those that did meet white glove

because they had so much more cleaning and whatever remaining soiling that led to the white

glove failures was not highly related to recoverable lead content.

It is important to reiterate the point previously made about the number of DCCs used in

this field evaluation compared to what would be used in a real-world application of the protocol. 

The very high numbers of DCCs used in this field study were the result of minimal initial

cleaning of surfaces and this minimal cleaning was intentional to allow an evaluation of the

DCC/WG clearance protocols in the worst case scenario (i.e., an inadequate cleanup after R&R).

Effectively, some portion of the DCCs used in the field evaluation were principally serving as a

cleaning tool and not as a clearance evaluation (though, of course, the two purposes cannot be

strictly separated). In a real-world incorporation of these protocols, it is expected that a more

efficient cleaning step would be mandated before application of the DCC/WG clearance protocol.

6.3 Additional Results and Discussion

When examining the results from this study across the different data quality objectives,

some results and conclusions appear that are global rather than isolated to one DQO. This

section presents each of these different issues. 
Final Report 52 December 28, 2005

6.3.1 Effect of Reaching White Glove on Efficacy of Treatment

From Table 7, it is noteworthy that only 37 out of 58 floors passed the white glove test for

the wet treatment as compared to 47 out of 58 floors for the dry treatment. The experiences of

those performing the protocol was that white glove could be reached more often for the dry

treatment than the wet. After the dry treatment had removed any non-adhering dirt and dust,

subsequent dry DCCs would appear white even if there was significant visible dirt and grime

remaining on the surface. Though dry DCCs could not pick up this remaining dirt, the clearance

wipe sample collection could. This effect would account for the lower observed success rate of

the dry treatment in predicting clearance has been met. Conversely, the wet treatment sometimes

could not reach white glove (i.e., wet DCCs continued to be discolored after mopping) even

though visual inspection of the surface showed no remaining dirt or dust. A very interesting

result of this study, as shown in Table 7, was that the effectiveness of the wet protocol on floors

when white glove was achieved (36 of 37 = 97.3%) was almost identical to the effectiveness

when white glove was not achieved (20 of 21 = 95.2%). This suggests that whatever material

continued to discolor the wet DCCs (and result in white glove failures) may not have been a lead

reservoir. These materials might include bits of the floor finish or even of the flooring itself. 

6.3.2 Representativeness of Field Study Locations to R&R Population

The data collected from the field study are representative of a certain population of realworld housing units. To address the applicability of the proposed clearance testing protocol to

the R&R population in general, it is necessary to determine to what extent the field study units

reflect the R&R population at large. One indicator that the sample from this field study is

“representative” would be if the lead levels encountered before application of the protocol are

consistent with R&R experience. No source is known for true R&R experience but two studies

provide some relevancy to this issue. 

The EPA report “Analysis of Lead Dust Clearance Testing,” EPA 747-R-01-005,

December 2001, includes a summary of first site visit wipe sampling results across eight different

sources, collected over the period from 1989 to 1999, in lead hazard control and abatement

locations. For these sources, the median lead loadings ranged, on floors, from 5 to 48 :g/ft2 and

the 90th percentiles from 68 to 418 :g/ft2. On sills, the median ranged from 17 to 443 :g/ft2 and

the 90th percentiles from 175 to 1624 :g/ft2. For the present field study, the median level before

applying the DCC/WG clearance protocol (counting only those surfaces which would ultimately

achieve white glove) was 48 :g/ft2 with a 90th percentile of 202 :g/ft2 on floors and 45 :g/ft2 with

a 90th percentile of 401 :g/ft2

 on sills. The similar median and 90th percentile values for all floors

(including those where the DCC/WG clearance protocol did not achieve white glove) were 56

:g/ft2 and 225 :g/ft2, respectively. On sills, the median and 90th percentile of all surfaces in the

field study were 63 :g/ft2

 and 703 :g/ft2

, respectively. Hence, it would appear that the lead

levels encountered in the field study are at least similar to those found in lead hazard control and

abatement programs.
Final Report 53 December 28, 2005

The report, “Lead Exposure Associated with Renovation and Remodeling Activities:

Environmental Field Sampling Study, Volume I: Technical Report,” EPA 747-R-96-007, May

1997 provides information on lead levels encountered after performing some types of R&R work

and subsequent cleanup. The evaluations in this study were simulated and are not necessarily

representative of real-world R&R work. However, they do provide insight into the lead levels

that might be encountered under certain types of work practices. Specifically, drilling followed

by a broom or vacuum cleanup of floor areas resulted in mean post-cleanup lead levels of 130

and 147 :g/ft2, respectively, at five to six feet from the activity. Abrasive sanding followed by

the same two cleanup methods produced even higher average post-cleanup measurements; 865

and 357 :g/ft2, respectively. These levels are higher, on average, than what was encountered in

the field study. However, it should be noted that each estimate has a fairly large uncertainty

associated with it and that the types of cleanup evaluated (broom and vacuum) are not expected

to be adequate in conjunction with the DCC/WG clearance protocol.

In addition to the lead loading levels, the experience of the field study suggests that

surface condition (both in terms of deterioration and cleanliness) is an important factor in

determining the effectiveness of the DCC/WG clearance protocol. The general impression of the

team conducting the study was that the selection of the units in this study resulted in a

disproportionate number of residences with surfaces in poorer condition than they encounter in

their normal lead hazard control and abatement work.
Final Report 54 December 28, 2005

7.0 CONCLUSIONS

Several important conclusions are suggested by the analysis of the residential field study

data.

Wet Treatment of DCC/WG Clearance Protocol Very Successful

In every case for sills and in all but one case for floors, when the wet treatment was used

and white glove was attained, the average wipe sample results confirmed that the surface was

below the clearance standard. On floors, the protocol was estimated to be 97.3% successful with

lower 95% confidence bound of 87.8%. On sills, the protocol was estimated to be 100%

successful with lower 95% confidence bound of 88.7%. Success is the positive predictive value

of the protocol and is defined as the ratio of true positive results (protocol achieves white glove

and clearance standard is met) to all results that achieved white glove. The relatively

conservative lower confidence bounds for the results are a result of the small sample of units in

the study.

While the number of units was small, the results comprise housing units in two different

cities, using a number of different sampling personnel, and covering a range of floor sizes, types,

and conditions. The sampled units were primarily lead hazard control and abatement sites so no

definitive conclusion can be reached as to how representative they are of typical R&R locations.

Dry Treatment of DCC/WG Clearance Protocol Not as Good as Wet

The dry treatment results for floors and sills in the field study were not as good as the wet

treatment results, but not different enough to be statistically significant.

The dry treatment in the field study was less effective at reducing floor lead levels than a

similar treatment evaluated in the Second Controlled Room Study. It is believed that this may be

due to the more complex nature of the lead contamination in the real-world environment (e.g.,

ground-in dirt and grime) than what was simulated in the controlled room experiment (e.g.,

sprinkled, misted, and dried lead-dust).

Dry + 1 Wet Treatment of DCC/WG Clearance Protocol Less Effective Than Dry

The hybrid treatment of the dry DCC/WG clearance protocol followed by one additional

wet DCC (evaluated on floors only) was the poorest performing protocol on average, though it

was not statistically significant in comparison to the other treatments. A version of this protocol

had quite strong results in limited testing for the Second Controlled Room Study. Hence, it

might still offer promise but would likely need to be re-evaluated and possibly re-defined (i.e.,

more than one wet DCC). The one drawback of this hybrid protocol will always be the need to

have both dry and wet DCC equipment and supplies.
Final Report 55 December 28, 2005

“Smooth and Cleanable” Criteria Important Operationally

The selection of sampling surfaces based on “smooth and cleanable” criteria likely will be

an important part of any guidance. Contrary to expectations, the floor surfaces sampled that did

not strictly meet these requirements often displayed positive results in predicting clearance.

However, the criteria are important to the practical execution of any protocol.

No Other Covariate Results Were Definitively Linked to Treatment Performance

No significant effects were observed for the covariates of surface area, surface material

type, and surface condition in bivariate analysis. Also, no significant effect was found for mop

manufacturer and cleaning solution (manufacturer’s solution versus plain water). More complex

multivariate analyses were not possible based on the limited amount of data obtained. Lack of

findings here should not necessarily be interpreted to mean that there are no covariate effects, just

that none were obvious from the limited sample of data in this study.

Failure to Reach White Glove Not a Good Indicator of Failing to Achieve Clearance

Standard

Among the small sample of units where white glove could not be reached using one of

the treatments, the post-treatment wipe samples showed in most cases that clearance had been

achieved anyway. Epidemiologically, this can be interpreted as the tested protocol having a poor

negative predictive value, where negative predictive value is the ratio of true negative results

(failed to achieve white glove and lead level is above clearance standard) to all results that failed

to reach white glove.
Final Report 56 December 28, 2005

8.0 PEER REVIEW

EPA put the current study through a rigorous peer review process. This provided key

stakeholders and experts in the field of lead hazard control and mitigation the opportunity to

assess the importance of the study results and to provide critical feedback. This section of the

report summarizes the results of the peer review. Section 8.1 provides background on the peer

review. Section 8.2 identifies several of the key points uncovered in the peer review process and

provides EPA responses. Additionally, many minor editorial issues were identified in the peer

review process. These are not explicitly identified but they have been incorporated in the final

report from this study.

8.1 Peer Review Background

A draft version of the current report was prepared in early August of 2005. EPA provided

this draft in addition to a set of charge questions to a contractor that organized the peer review. 

EPA requested the peer review panel collectively include individuals with all the following

qualifications:

• Employees of the Federal Government with experience in measuring exposure to lead

dust in residential settings, preferably including experience in sampling and lead

clearance testing. EPA requested that two reviewers be recruited for this category, but not

from the same Federal agency.

• Employees of state, city, or local governments with experience in measuring exposure to

lead dust in residential settings, preferably including experience in sampling and lead

clearance testing. EPA requested that one or two individuals be selected from this

category.

• At least one statistician who is familiar with residential lead dust contamination and is

capable of evaluating variation and uncertainty in indoor air data. Ideally, this reviewer

would have a M.S. or Ph.D. in Statistics.

• One individual from the private sector with professional experience in lead dust

sampling, especially sampling in indoor environments.

• One chemist with knowledge and experience in lead sampling. In particular, extensive

experience in analyzing wipe samples is important.

A panel of six individuals was selected that collectively met all the requirements above. 

Each reviewer received a copy of the draft report and a set of charge questions from EPA. These

questions included four general and nine specific questions about the report and the prospect of

implementing the technology examined in the report. Additionally, all reviewers were

encouraged to provide any additional thoughts that would be useful to EPA. The reviewers were

given approximately one month to complete their reviews.
Final Report 57 December 28, 2005

8.2 Peer Review Results

Upon their receipt, EPA carefully reviewed the collective peer review responses. In some

cases, EPA contacted the peer reviewer to obtain additional clarification. The general impression

of the peer reviewers were positive to the report and to the prospects of using the DCC/WG

protocol. However, some important questions were raised and criticisms leveled.

The issues listed below were selected as the most important due either to their prevalence

(i.e., a comment appearing from multiple reviewers) or their potential impact to the

implementation of the study results in EPA’s R&R rulemaking process. In this latter category,

comments made by the HUD lead program personnel were particularly important (whether or not

their comments were shared by other peer reviewers). Following each key issue is a response

from EPA.

1) Reviewers indicated that the overall sample size for the study was small.

EPA Response: A total of 58 separate floor surfaces and 29 window sills from 31 residential

sites located in 2 cities (with documented lead-based paint hazards) were included in this field

study. Every floor surface (58 floors) was divided into two areas that were treated by different

DCC protocols. Two wipe samples were collected and analyzed both before and after DCC

treatment for each treatment area. While this field study was not large, it was nevertheless a

major research effort in which a substantial amount of empirical data was collected. This field

study systematically explored the effectiveness of the DCC/WG testing protocol under a variety

of challenging real world conditions. 

In addition, the field study employed essentially the same DCC testing protocol that had already

been thoroughly tested under controlled laboratory conditions. The lab results were consistent

with the findings from the field study. EPA believes that both the quality and quantity of the data

was sufficient to conclude that the DCC method is useful and reliable for the proposed use. 

2) Reviewers indicated that sites and work activities were not (or may not have been)

representative of R&R work.

EPA Response: The residential units used for this field study included both lead hazard

reduction and R&R project sites. A wide, overlapping range of work activities are shared by

both lead hazard reduction and R&R (e.g. sanding, scraping, cutting, drilling). At virtually every

site where data was collected, some work had been done prior to data collection. EPA has no

reason to believe the actual mix of work activities at each site and the particular sites employed

in this study are in any way atypical of R&R work. To actually attempt to define what constitutes

a representative mix of R&R work activities and then ensure that those activities were employed

at these work sites would have presented an almost impossible logistical challenge for

completion of this field study. EPA feels that it was better to view 'work activities' as a random

effect for the purposes of this study design. That is, a random set of work activities that might

reasonably be expected to occur as part of R&R work were believed to have been conducted at
Final Report 58 December 28, 2005

these sites, but there was no attempt to document or control for specific work activities.

3) Reviewers commented on the challenge of defining "Smooth and Cleanable" floors.

EPA Response: For the purpose of the field study, some floors were excluded. Based on

experience in some of the first units tested, floor surfaces that were expected to tear or damage

the disposable cleaning cloths (DCCs) were dropped. Floors that were excluded from testing

typically had broken or splintering wood or the floor surface/finish was so rough that it would

have caught on and torn the DCCs. 

Surprisingly and unexpectedly, for those floors with rough or deteriorated surfaces that were

tested before rough floors were dropped, they often did not pass the 'white glove' test, but most of

them still had post-treatment lead levels below the Federal hazard standard. 

4) Reviewers noted that the Unit 08 field blank did not yield the expected “zero” result but

that the remaining protocol wipe samples were not eliminated from study consideration.

EPA Response: The QA procedure for an unusual result (either a failed quality sample or an

outlier) is to examine the sample logs and other available information to identify if any

explanation can be found for the anomalous record. If none is found, the unusual observation is

identified in the results but the original data is not removed. This is the process that was

employed for this case. 

Additionally, EPA thinks it important to point out this result in context of the entire study. The

purpose of the field blanks was to provide assurance that the multiple wipe samples taken in a

lead contaminated field environment had minimal risk of being cross-contaminated. The fact

that only 1 of 31 field blanks showed lead contamination above the method detection limit and

this was at a relatively modest level actually provides assurance that the field data collection

procedures minimized the potential for errors dues to cross-contamination.

5) Reviewers expressed concern about the large number of QAPP modifications.

EPA Response: The relatively large number of QAPP modifications (14) reflects the extreme

care that was taken in documenting even minor changes in the planned study protocol. Since this

field study was conducted at sites that displayed considerable variation in their physical

characteristics, a number of adjustments to the data collection protocol were necessary. Even

minor adjustments were carefully and thoroughly documented in the QAPP.

6) Review pointed out that the DCC/WG protocol may lead to extra, unnecessary cleaning.

EPA Response: EPA acknowledges that the DCC/WG protocol may sometimes result in extra

cleaning of floors. In order to insure a high level of confidence that the floor lead level falls

below the Federal hazard standard when white glove is achieved, extra cleaning may occur. The

trade-off of employing a method that may require extra, unnecessary cleaning to save the time

and expense associated with the use of wipe sampling appears worthwhile.
Final Report 59 December 28, 2005

In addition, it must be noted that only a perfunctory broom sweep of each floor was performed

prior to DCC treatment. This was done to increase the likelihood that a range of 'higher' lead

loadings would be encountered during the field study. In actual practice, the DCC/WG protocol

would be implemented after a thorough cleanup had been completed, so fewer DCC treatments

would be likely to occur than were needed in the study. Hence, while additional cleaning may

occur in an implemented version of the protocol, it is expected that its prevalence would be a

lower proportion than was observed in this field study. 

7) Review identified a possible bias from spike laboratory QA sample results.

EPA Response: The recovery (average bias) for the 20 :g samples is 90.5% and for the 40 :g

samples is 90.8%. This observed bias may have been related to the preparation of the spike

samples, either through the methodology employed in spiking sample wipes or as a result of bias

inherent in the SRM material. In this case, the bias should have had no effect on the laboratory

wipe sample analysis. However, under the assumption that the observed bias is a true laboratory

measurement bias and that this bias is consistent throughout the study, the study results were

recast assuming the true measured lead levels should have been a factor of 10/9 greater than

observed. In this process, very little difference was found in the study results and no changes

were found for the key data quality objective of protocol success rates. This observation has

been added into the report.

8) Reviewers questioned the omission of window troughs.

EPA Response: Testing of window troughs is a component of Lead Abatement Clearance testing. 

Testing of troughs is not a part of the proposed post-cleanup testing for R&R. This has been

identified as a footnote to the report in the Executive Summary section.
Final Report 60 December 28, 2005

9.0 QUALITY ASSURANCE

This study featured a thorough and rigorous quality assurance process. This process was

embodied in two key components of the study:

1) The Quality Assurance Project Plan (QAPP) - The QAPP is a formal document prepared in

advance of the study, signed by all key personnel, and includes the detailed instructions on

performing the field study procedures. It has been incorporated in its entirety into the current

study report as Appendix A. Among its most important elements with regard to quality are:

• The key staff working on the study, their qualifications, and their roles.

• An objective for the study accompanied by a set of data quality objectives to assess this

objective. These DQOs are included in Section 3.1 of this document and they form the

basis of reporting the results of this study in Section 6.2.

• Specifications for procedures regarding sample handling and custody as well as study

documentation and records.

• Detailed specification of the study design, the protocols to be completed, and the

analytical methods to be employed. Each of these components have also been thoroughly

documented in the final report with study design and protocols in section 3.1 through 3.4,

and 4.1. The analytical methods are discussed in section 5.1.

• Quality control procedures including quality control samples as well as procedures for

data review, validation, and verification. The results of the quality control samples are

discussed in section 5.2.

• Procedures for data review, validation, and verification as well as the planned

calculations of final study estimates. The results and discussion of same are provided in

section 4.2 and throughout Section 6.

2) The Peer Review - An important final component to quality assurance for this study was

subjecting the results to a review by professionals of several different disciplines with experience

in the field of lead hazard control and removal. This peer review is documented in Section 8 of

the report.