Comparison of the Alternative Asbestos Control Method and the NESHAP Method for Demolition of Asbestos-Containing Buildings

Comments by Andrew F. Oberta, MPH, CIH
The Environmental Consultancy

June 4 , 2007

INTRODUCTION AND SUMMARY
The findings of my review are summarized below and explained in detail in the body of this submittal.

• Two 4,500 ft² buildings, each containing 3,992 ft² of asbestos-containing floor tile and mastic plus 252 ft² of linoleum with friable asbestos-containing backing, were demolished in a demonstration at Fort Chaffee , AR. The first building demolished had 20,700 ft² of asbestos-containing wallboard removed immediately before the demolition, which was performed essentially dry. The wallboard was not removed from the second building but was saturated before demolition. A foaming agent was added to the water for dust suppression during the second demolition.

Figure 4-17. Starting demolition of the NESHAP building.	Figure 4-32. Progressing with the AACM demolition.
Photos from EPA report

• Soil samples collected after demolition of both buildings contained a substantial amount of asbestos-containing debris from the floor tile, linoleum and possibly previously-removed pipe insulation. The samples from the first building demolished (the “NESHAP” building) had more debris than those from the second (“AACM”) building. These results suggest that asbestos-containing flooring materials should be removed before demolition of a building, particularly if the minimal amount of water used for dust suppression during the NESHAP demolition represents customary practices.

• Leaving the flooring materials in the buildings introduced a variable not discussed in the report. These materials represent a source of airborne fiber release that could have affected the air sampling results. The implied assumption that no such fiber release occurred or that it affected the results for both tests equally is not defensible.

• The air sampling results used to compare the two methods were inconclusive, primarily due to the large percentage of samples with zero structure counts. If anything, the results faintly suggest that the AACM creates higher airborne asbestos concentrations than the NESHAP method. No effort was made to compare the airborne asbestos concentrations during either demolition to background levels or prevailing urban ambient concentrations.

• The AACM demolition was preceded by saturating the wallboard with water containing a foaming agent, which was also sprayed on the building as it was demolished. Whether a contractor demolishing a building for low bid would spend the time and money to use this method properly, or would be able to maintain the spray equipment and calibrate the mixture, is very doubtful based on my experience on asbestos abatement projects.

• The purported cost savings of 47% for the AACM compared to the NESHAP method are reduced to 31% when expenses for necessary preparation and oversight by the owner's representative and training of the contractor's workers are included. The biggest and most unpredictable cost variable, as acknowledged in the report, is the competitive nature of bidding for demolition work.

• There are numerous technical errors, inconsistencies and questionable items in the report. ASTM and ISO methods for sampling and analysis are misrepresented. Prevailing industry practices described in ASTM asbestos control standards are not recognized.

The following statement appears on page 1 of the Introduction: “These data may be used to help EPA determine whether it is appropriate to include an alternative method in the current asbestos regulations contained in 40 CFR Part 61 Subpart M.” If this statement signals EPA's intentions to amend the NESHAP to allow use of the AACM, it would be a serious mistake and compromise the protection of health and the environment. Exhibit 1 appears to represent a potential draft of the regulatory language that would describe how the AACM is to be used. This Exhibit has serious flaws, the foremost of which is allowing several asbestos-containing materials (ACM) to remain in the building during demolition that should be removed. An equally serious omission from the exhibit is any consideration of vacating or protecting nearby residences and businesses, and measures to assure occupants of the safety of moving back into them.

I cannot endorse the AACM on the basis of this report any more than I could before the tests were conducted. If the NESHAP is amended to allow its use, my recommendation to building owners would be to follow the advice of a qualified asbestos professional who has inspected the building according to ASTM E2356 Standard Practice for Comprehensive Building Asbestos Surveys (www.astm.org) and made an informed decision as to whether any asbestos-containing materials (ACM) can remain in place during the demolition. The project should be conducted in the same stringent manner as any other abatement project, which is what the AACM amounts to. This includes a project design and proper oversight by the owner's representative and compliance with applicable state and local asbestos regulations. This is the only way that health and the environment can be adequately protected and that the owner can avoid possible liability including citations from regulatory authorities.

DISCUSSION

Section 1 Introduction – A schedule showing the activities performed each day would help greatly in understanding the sequence and timing of events. Currently, this information has to be dug out of the text.

Exhibit 1, 2.0 Applicability – Is there a limit on the size of a building (floor space) other than the height and number of stories? It is conceivable that a 100,000 ft² single-story building could be demolished under these requirements.

Exhibit 1, 3.0 Building Inspection/Asbestos Assessment -- An “AHERA” inspection is not “comprehensive” because it allows exclusions for sampling and assessment based on friability and location of suspect materials. Exterior materials that are required to be sampled are specifically enumerated and non-friable materials are not assessed. Inspections for pre-demolition abatement projects should be done according to ASTM E2356 Standard Practice for Comprehensive Building Asbestos Surveys as Project Design Surveys, which requires all ACM regardless of friability and location to be identified.

Exhibit 1, 5.2 Wetting Process – Even amended water will not penetrate non-friable materials such as floor tile and asbestos-cement roofing or siding that the AACM allows to be left in place. A surfactant will, at best, allow the water to spread over the surface and contribute to the control of dust. However, the product used in this demonstration in no way resembles the amended water commonly used by abatement contractors.

This procedure assumes the existence of an attic, which I take to include a plenum above a lay-in or solid ceiling. Is the procedure modified if there is no attic or plenum?

Exhibit 1, Table 1 – ASTM E2356 discusses some of these materials in Appendix X1. SAM PLI NG TECHNIQUES AND EQUI PMENT in ways that suggest they should be removed prior to demolition rather than left in place according to Table 1.

Spray-applied surface coatings (popcorn ceiling) are covered in E2356 under X1.3.2.3 Textured Finishes and Spray applied acoustical or decorative surfacing is covered under X1.3.2.2 Plaster as friable materials. The ability to wet these inherently-dusty materials sufficiently to minimize the release of airborne fibers and debris with the AACM was not demonstrated. They should be removed before demolition.

Troweled-on crows foot texture, splatter texture, and joint compound combines very dissimilar materials. Joint compound is covered under X1.3.3.3 Wallboard Systems as a friable miscellaneous material along with texturizer, or skim coat, and the tape covering the joint. OSHA posted an interpretation on May 14, 1998 titled “Asbestos standard: Joint compound is not a surfacing material.” A decision on whether these materials must be removed before demolition should be made by the project designer on the basis of multi-layer sampling and analysis.

Vibration-dampening cloths are covered under X1.3.3.5 Vibration Dampeners as a friable material. These items are woven from almost-pure chrysotile fiber and should be removed before demolition.

Linoleum or other floor tile are distinctly different materials. Linoleum is covered under X1.3.3.4 Sheet Vinyl Flooring containing a woven or matted backing with a high chrysotile content that is very friable. If this backing is present the flooring should be removed before demolition as the amended water will not penetrate the vinyl facing.

Ceiling tile is covered under X1.3.3.1 Acoustical Ceiling Tiles as a friable material, as are X1.3.3.2 Glued-on Tiles . The former often contain amosite and the latter may be attached to the deck or ceiling with asbestos-containing mastic. These tiles should be removed before demolition as the ability of the AACM wetting agent to penetrate to the substrate has not been demonstrated.

Examples of the above materials
"Popcorn" ceiling	Wallboard joint compound	Vibration dampener	Linoleum and backing	Glued-on ceiling tiles

The decision whether to remove any ACM or leave it in place during demolition should be left to the project designer with a default to removal if the possibility exists of generating debris or releasing fibers.

Exhibit 1, 5.3 Demolition Process and 5.4 Visible Emissions – It may be as naïve to expect the demolition contractor to “minimize breakage of asbestos-containing materials” as to expect the demolition contractor's NESHAP-trained individual “to stop work if visible emissions are observed.” The AACM process suffers from the same lack of independent oversight by the owner's representative as the current NESHAP. Fortunately, such oversight is required by some state regulations as well as consensus standards such as ASTM E1368 Standard Practice for Visual Inspection of Asbestos Abatement Projects.

2.1 Primary Objectives – Primary Objective 2 states: “The AACM requires soil excavation following demolition and the NESHAP Method does not.” Why not? As seen later, the soil around the NESHAP building was just as contaminated after demolition as the soil around the AACM building.

Primary Objective 4 should be to compare airborne asbestos (TEM) concentrations during the NESHAP and AACM demolitions to the background TEM concentrations and to prevailing urban ambient concentrations.

2.2.3 Worker -- Objective 9a should be to determine whether worker exposure using the AACM can be statistically shown to comply with the OSHA Permissible Exposure Limits of 0.1 f/cc for an 8-hr TWA and 1.0 f/cc for the 30-minute excursion level. Comparisons are made later in the report (4.1.3.3.3 and 6.1.5.1) but no statistical analysis was performed.

3.2 Site Description – Most buildings that the AACM appears intended for will not have had the benefit of previous asbestos abatement. They may also have been subject to maintenance, vandalism, neglect and other activities that result in disturbance of asbestos-containing materials and the presence of debris that would need to be cleaned up before an AACM demolition began.

3.3.1 Asbestos Inspection of Buildings – Reference has previously been made to the limitations of an “AHERA” inspection and to ASTM E2356 Standard Practice for Comprehensive Building Asbestos Surveys. Figure 3-5 in the Draft Report has been cropped horizontally from Figure 1 in the EEG inspection report, which shows a section approximately 3.5” wide. As the EEG report states on page 9 that 2” and 3” hole saws were used to obtain the samples, the question is whether this picture is on a section through a joint that was not a sample but obtained separately.

Figure 3-5. Section of ½-inch gypsum wallboard showing a multi-layered joint interval.	Figure 1. Section of ½-inch gypsum wallboard showing a multi-layered joint interval.
Photo from EPA report	Photo from EEG report

What is labeled “joint compound” in the EEG Figure 1 is ~1/8” thick at the edges of the picture and does not appear to decrease in thickness. This suggests it may be a layer of plaster and not joint compound, which would make it surfacing material. Were any samples taken of this material between the joints? The answer affects the relative contributions of this layer and the flooring materials. If 20,700 ft² of wallboard is covered with 1/8” of plaster containing 10 – 19% asbestos, the amount of asbestos available for release from this plaster is roughly five times that in the 4,244 ft² of floor tile and linoleum backing of equal thickness with 10 - 25% asbestos. If, however, only the joint compound itself – between the wallboard sheets at four foot intervals – contains asbestos, the flooring materials constitute a much larger, even a predominant, amount of potential fiber release.

The EEG report also states “ In the laboratory the full-depth core sample was separated into its discrete layers ( Figure 1 ) for analysis.” Was this done using the dimension d2 in Figure 3-5 of the Draft Report? What is the basis for the width of the seam in the absence of joint tape or other defining components of the wallboard system? The “Joint Interval Composite” percents in Table 3-1 calculated from these dimensions should not depend on an arbitrary reference point.

Wallboard joint compound doesn't cover the entire surface of the wall. The wallboard joint is a complex structure.

Table 3-1 has a single line for mastic in each building, whereas the lab reports (EEG pages 110 – 115 of PDF file) show brown/tan for the linoleum and black for the tile. The latter was not gravimetrically analyzed as a separate layer, even though it qualifies as a non-friable organically bound (NOB) and has a high probability of containing asbestos.

The lab reports also list a white tape as part of the joint sample, which is not listed in Table 3-1 or in the body of the EEG report and is not apparent in the photos.

3.3.3 Concentrations of Asbestos in Soil – When were these (nine) samples taken? They do not appear to be the same (ten) samples for each building that appear in the remainder of the report.

4.1.3.1 Background Air Monitoring – Are these the samples in Table A-4 that were taken on January 11, 2006 ? Where were these samplers in relation to those shown in Figure 4-1? The report states that these samples were taken “to collect data necessary for potential comparison of air concentrations of asbestos and total fibers during demolition.” However, it is not clear what comparison is meant here, and the concentrations during the demolitions were not compared to background levels.

4.1.3.2 Perimeter Air Asbestos, Total Fibers, Settled Dust, and Particulate Sampling During Demolition – Page 30, 5th paragraph: The pumps shown are capable of pulling more than 4 lpm. Although the 1920 – 2400 L volumes exceed that for ambient samples at many abatement sites, higher volumes would have increased the number of samples with one or more structures counted. Once it became apparent that filter over-loading was not a problem, was any consideration given to increasing the flow rate and thus the sample volumes?

4.1.3.3.1 Discharge Air Sampling During Asbestos Abatement of NESHAP Building – In response to an inquiry, EPA informed me that the isokinetic sampling was done according to the following reference: Quantitative Evaluation of HEPA Filtration Systems at Asbestos Abatement Sites, Roger C. Wilmoth et al. Environmental Choices Technical Supplement , Vol. 2, No. 1, Fall 1993. Environmental Information Association, Chevy Chase , MD. This article describes a series of tests where samples were taken in ducts attached to HEPA-filtration units. To achieve isokinetic velocity, the cap was left on the 25mm cassettes, which presumably faced into the airstream, the plug removed and a tube inserted into the hole. The filters were analyzed by TEM with indirect preparation to overcome the problem (not discussed in the article) of uneven fiber distribution on the filter. This methodology is not described in this Draft Report and without information on the air flow rates through the HEPA-filtration units and the sampling cassettes, and the diameter of the inlet tube, the existence of isokineticity cannot be confirmed.

One learns from Table 4-1 that these filters were analyzed by TEM but Tables 5-1 and 5-2 do not mention them. However, Table 6-16 also gives results for PCM analysis in f/cm³, which raises the question of how fiber counts were done on asymmetrically-loaded filters that were also indirectly-prepped for TEM analysis. It is implied that ISO 10312 was used but that is a direct prep method.

4.1.3.3.2 Personal Breathing Zone Sampling During Abatement -- With ~81 man-days of abatement, why were only six personal samples collected for worker exposure? On which day out of the nine during which abatement was conducted were these samples taken?

4.1.3.3.3 Personal Breathing Zone Sampling During Demolition – I believe the text should read: “ For each of the two building demolitions, samples were collected during the sampling demolition periods to calculate the time-weighted average (TWA) concentration for comparison to the OSHA Permissible Exposure Limit for Asbestos (29 CFR §1926.1101)..” However, Objectives 8 and 9 refer to comparing concentrations between the NESHAP and AACM methods – comparison to the OSHA PELs would be an additional objective, which is identified in my comment on 2.2.3.

No personal samples were taken during pre-wetting of the AACM building on the day before it was demolished. During this time the workers were dragging hoses through the building, moving ladders and doing other things that could have released airborne fibers from the asbestos-containing wallboard joint compound. Their exposure should have been monitored.

APPENDIX C Procedures for Visual Inspection and Clearance of Project Sequence of the EEG SPECIFICATIONS & DRAWINGS FOR ASBESTOS ABATEMENT PROJECT requires a visual inspection that closely follows the sequence in ASTM E1368 Standard Practice for Visual Inspection of Asbestos Abatement Projects and clearance by air sampling with PCM analysis. Other than a statement here that “ The EPA and contractor staff inspected the abated area following acceptance …” and another in Section 8 about “… clearance testing by a licensed asbestos consultant;” there is no mention in this Draft Report that the visual inspection and clearance procedures in the specification were carried out. There are no air sample results for the clearance testing.

4.3.3 Cross-contamination control – Imagine yourself living in a house across the street from one being demolished by the AACM. You would ask the following questions: "Will my family be re-located during the work and at whose expense? Will my house and yard be covered with plastic as in Figure 4-16? Will my house and yard be inspected and cleaned if necessary so it is safe to move back in?" These questions may not have arisen in the context of this demonstration project but will undoubtedly be asked if an AACM demolition is proposed.

Figure 4-16. Preparation of site prior to demolition of NESHAP Method building (left).

Photo from EPA report

4.4.2.1 Amended Water System – Page 49: The Kidde Fire Fighting NF-3000 Class “A” Foam Concentrate is a respiratory, eye and skin irritant according to the MSDS and handling it requires appropriate PPE. Figure 4-25 shows a worker wearing a full-facepiece negative pressure respirator with P100 cartridges during application of the foam, but would a demolition contractor have the necessary PPE for the workers who are handling the concentrate?

Page 50, 1st paragraph: What would the cost be for such a system if a contractor had to buy or rent it?

The remainder of page 50, Table 4-4 and Figure 4-22 describe conductivity measurements to calibrate the foam concentration. Is it realistic to expect a contractor to do this on an actual project under time and cost constraints?

4.4.2.2 AACM Pre-Wetting – Would ordinary amended or just soapy water have saturated the walls and ceilings equally as well as the foam? Is the foam necessary to penetrating the wallboard or does it just sit on the surface?

4.4.2.3 AACM Demolition Phase – Page 52, last paragraph, describes problems with the foaming nozzles, which appear related to the footnotes to Table 4-4 about “non-foam proportioning.” Even the simple spray equipment used at abatement sites frequently malfunctions and workers are continually cleaning, adjusting and repairing the spray nozzles and pumps. If the AACM depends on using a complicated foaming device as was done on this project, contractors will not spend the time to keep it operating properly. They will just spray the building with amended (or plain) water, which may be adequate for the purpose intended, but this project did not show that to be the case.

5.2.4.1 Soil Preparation – Under what magnification was the soil examined for the presence of building debris? Was the mass of the debris pieces determined by weighing them or by inference from the PLM visual estimate?

5.2.4.2 Soil Analysis (TEM and PLM) – The pieces of debris that were picked out of the soil don't seem to have been subjected to the same gravimetric and point-counting procedures as the soil, which included the pieces of debris that were not removed.

5.2.5 Settled Dust Samples (TEM) – The reference to ASTM D5755 in this paragraph and Tables 5-1 and 5-2 is inappropriate. These samples were not collected, prepared or analyzed according to either D5755 or D1739 (referenced in 5.1.6) but a combination of methods loosely resembling both.

• D1739 requires gravimetric analysis, not TEM. It is meant to measure particulate fallout, not fibers or structures.
• D5755 requires microvacuum sampling of surfaces. There is no apparent reason why this could not have been done.
• The fallout container had a volume of 5555 cm³, a surface area of 1642 cm² and was rinsed with 300 ml of solution. The cassette used in the D5755 method has a volume of 25 cm³ and a surface area of 47 cm²; it is filled with 10 ml of rinse solution and shaken, then this solution is added to 75 ml used to further rinse the cassette.
• D5755 uses an indirect preparation method for TEM analysis of aliquots from the rinse solution that are filtered; the cassette filter is not analyzed. ISO 10312 is a direct preparation method where the filter in the cassette is analyzed by TEM.
• D5755 and ISO 10312 have different grid opening requirements and stopping rules (Tables 5-1 and 5-2).

The settled dust (mud?) results are of little consequence to this study and the method certainly would not be used on an actual project. However, the deviations from the referenced ASTM and ISO methods should have been more fully explained.

Section 6 RESULTS – Due to the large number of non-detects, the conclusions are based more on the absence of asbestos structures in the samples than on their presence. The statement at the top of page 74 may be more candid and revealing than the authors intended: “…any conclusions that are based upon counts less than four, as almost all the ones in this study were, should be used with some caution.”

6.1.2.1.2 Demolition Air – The highest recorded concentrations are 0.0015 s/cm³ for the NESHAP building and 0.0019 f/cm³ for the AACM building. These are compared – favorably – on page 80 to various clearance limits in the US. Other countries have stricter limits, e.g. the guidance limit in Israel for asbestos in ambient air is 0.0014 f/cm³ measured by SEM. Moreover, the limits in the penultimate paragraph on page 80 are not directly comparable: the AHERA limit is based on analytical sensitivity and not a health-based standard; the AHERA, Katrina and WTC limits are for re-occupancy of indoor environments, not outdoor exposures. The last paragraph admits that the AACM demolition concentrations were statistically higher than the NESHAP values.

6.1.2.2 Asbestos in Settled Dust – A footnote to Table A-7 gives a surface area of 181.5 cm² that was presumably used to calculate the surface loading (not concentration as in the titles of Table 6-4 and Figure 6-6). This is the area of the bottom of the can. How were the bottoms of the cans rinsed without also rinsing the sides? It is hard to believe that all of the dust particles, water droplets and floating fibers fell straight down into the can without touching and sticking to the sides. If the sides were also rinsed, the total area of 1642 cm² should have been used in the calculations, which would reduce the surface loadings by almost an order of magnitude. This would place even the highest loadings below the WTC and Libby criteria, for what that is worth.

6.1.2.2.1.1 Background Air -- Table 6-5 is titled in part “…total fibers (PCM) prior to demolition…” and the units are f/cm³. However, Table A-4 lists 5 samples analyzed by TEM and none by PCM. No structures were counted on any of the filters, a fact not mentioned in this paragraph. Nor is it stated that the samples were taken four months before the demolitions and not immediately preceding the work.

Figure 4-2. Location of soil sampling grid around the NESHAP building.

Photo from EPA report (notations in original)

This illustration shows the soil sampling grid. The total area of the sampling grid (red lines) is 11088 ft² or 2.5x the floor space of the building. Ring 1 and Ring 2 refer to the locations of the air sampling pumps.

6.1.4.2.1 Soil Fraction – Table 6-11 summarizes the analyses of the soil fraction (Fraction 01) from which rocks/organics (Fraction 02) and building debris (Fraction 03) had been removed. Thus, the soil in Fraction 01 was at least “visibly clean” and, if examined under magnification, even cleaner. Fraction 01 was then separated into sub-fractions for analysis by TEM and point-counting (1000 points) by PLM. The sub-fractions were gravimetrically reduced by ashing and acid-rinsing before the analyses.

The text on page 90 doesn't mention the two pre-demolition AACM samples (9 and 10) with 0.11% and 0.33% asbestos by PLM/point-counting. If these percentages refer to the one-liter split for PLM/TEM ana;ysis (Fraction 01), the latter represents ~4 gm of asbestos, or ~0.15 ounce of floor tile or other debris. This is the equivalent of one square inch of floor tile, an amount that should have been visible -- even as fragments -- in one liter of soil. Perhaps it belonged in Fraction 03 and should have been transferred to that set of samples.

The conclusion that the pre-demolition debris came from pipe insulation is logical, as pipes ran in the crawl spaces under buildings such as these. This does not account for pre-demolition NESHAP sample 9, however, which was identified as VAT. The next italicized paragraph addresses Primary Objective 2, comparing post-excavation AACM soil to post-demolition NESHAP soil. First, I consider this a meaningless comparison. The comparison should have been to the post-demolition soil for both buildings.

Second, if post-demolition NESHAP sample 7 also refers to the one-liter split for PLM/TEM ana;ysis (Fraction 01), it similarly represents ~4 gm of asbestos that possibly should have been extracted and put in Fraction 03. Doing that would have changed the results in Table 6-11 and perhaps the conclusion for Primary Objective 2. This suggests that removing the building debris not only biased the analyses of Fraction 01 toward the low side but that it may have been done inconsistently. Needless to say, Fraction 03 was affected as well.

There is a very poor correlation between the PLM point-counting results and the TEM results for the two samples just discussed when one calculates the mass of asbestos on the filters. For post-demolition NESHAP sample 7, the 0.34% asbestos by PLM translates to 4.42E-07 gm while the 110 structures by TEM in the same sample gives 7.33E-08 gm, a 6x difference. For pre-demolition AACM sample 10, 0.33% by PLM gives 3.63E-07 gm vs 1.18E-08 gm for the 136 structures by TEM, a 30x difference. Are such variations typical when comparing PLM point-counting and TEM results from similar samples?

6.1.4.2.3 Building Debris Fraction -- What method was used to visually estimate the asbestos content of Fraction 03 by PLM to two decimal places? Were the debris fragments gravimetrically reduced or was a stratified point-count method used, or both? If the asbestos content could be visually estimated to two decimal places, why are some shown as “<1” percent? If these were visually estimated between 0,01% and 0,99% they should be shown as such. If no asbestos fibers were found, they are “ND” or 0%. The <1% regulatory definition of ACM has no meaning here.

The text on pages 93 and 94 attributes nearly all of the soil contamination to the VAT. Table A-13, which is not discussed in the text, shows this to be an exaggeration for the NESHAP building. Dividing sums of the VAT and “other” ACM weights by the sum of the weights of all the original samples gives 90% for the VAT and 10% for the “other,” not 98% and 2%. The “other” could have come from the backing on the linoleum or pipe insulation removed in 1999.

If the percents of building debris in Table 6-12 were determined by visual estimation and those in Table 6-13 by weighing the VAT fragments, the numbers are not directly comparable. If they were, one might conclude that the 0.28% mean weight of building debris in the NESHAP soil samples consisted of 0.07% VAT and 0.21% “other” debris. For the AACM samples it would be 0.07% VAT out of 0.87%, with 0.80% being “other” debris. This is not consistent with Table A-13.

Accepting the figures in Table 6-13, rough calculations show that the mean of 0.07% by weight of VAT fragments in the ½” deep post-demolition NESHAP soil samples is the equivalent of 18 ft² of VAT, or 0.46% of the total in the building. The AACM amount would be slightly higher. There would also be mastic associated with this debris. This would seem to be an unacceptable degree of soil contamination regardless of the abatement and demolitions methods used.

Figure 6-12. Weight fraction of soils that were VAT and ACM building debris.

Graphic from EPA report

NESHAP Post-Demo and AACM Post-Demo: This is clean soil?

The post-excavation AACM data in Table 6-13 and Figure 6-12 do not match the figures in Table A-13. The latter are identical to those for the post-demolition AACM samples immediately above, except for the number of decimal places. This appears to be an editorial mistake, but it renders comparison of these samples to any other sample set – for what it's worth – difficult.

6.1.5.1.1 Demolition and Abatement Workers -- To compare the entire sequence of both methods, Table 6-16 should show the exposure of the workers who pre-wet the AACM building. Unfortunately, no worker monitoring was performed during pre-wetting. Therefore, the conclusions at the end of this section are based on an incomplete data set.

6.1.5.1.3 The statement in the second paragraph refers only to the TEM samples. Figure 6-15 is missing exposure data for AACM workers during pre-wetting and the conclusions in the last paragraph reflect this omission.

SECTION 7 STATISTICAL ANALYSES – One of the primary objectives should have been to compare the airborne asbestos TEM concentrations during both demolitions to the background airborne asbestos TEM concentrations and to prevailing urban ambient air levels. Data for the background comparison, shown in Tables 6-5 and A-4, are unfortunately limited in number and all yielded zero structure counts. Still, the null hypothesis that the demolition did not raise airborne asbestos TEM concentrations above background should have been tested separately for both methods. Rejecting the null hypothesis casts doubt on the advisability of leaving floor tile and linoleum in a building during demolition.

Data on asbestos TEM concentrations in urban air have been published for many years, including a compilation in the HEI-AR report of 1991. More recent compilations are no doubt available. A statistical comparison of published ambient concentrations to the levels measured during demolition of the buildings would be of interest.

7.1 Primary Objective 1 – This objective compares airborne asbestos contamination during demolition of two buildings with 3,992 ft² of non-friable floor tile and its underlying mastic plus 252 ft² of linoleum with friable backing. The fact that the 20,700 ft² of wallboard in the NESHAP building had been “meticulously removed” had no bearing on contamination levels during demolition, assuming that the abatement, visual inspection and clearance testing were done according to the EEG specification. The wallboard remained in the AACM building but, unlike the NESHAP building, it was saturated and foamed during the demolition. Thus, the variables are the absence of the wallboard during essentially dry demolition (NESHAP) and presence of the wallboard during wet demolition (AACM) with the presence of floor tile, mastic and linoleum common to both.

The statistical analysis dealt largely with the handling of the non-detects -- zero structure counts -- due to the small number of positive samples where at least (and usually) one structure was detected. Thus, the conclusions are based more on what was not found on the filters than what was (barely) found. For no reason other than referencing the QAPP, data from Ring 2 were not used in this analysis, so a value of 0.0015 s/cm³ during the NESHAP demolition was ignored. The conclusion from the statistical analysis was that the airborne asbestos contamination generated during the AACM demolition was higher than during the NESHAP contamination. This does not argue well for acceptance of the AACM . How much the floor tile, fragments of which were found in the soil after demolition, and the linoleum backing contributed to the airborne concentrations is not known but could be significant as it may have affected the results of both demolitions differently. Was the assumption that the floor tile and linoleum would not contribute to the contamination levels, or that it would be the same for both buildings? Either would be a dangerous assumption.

7.2 Primary Objective 2 – The post-demolition NESHAP soil results for Fraction 01 on which this objective depends were questioned in my comments on 6.1.4.2.1. The other pertinent results are the post-excavation AACM Fraction 1 soil results. Table 7-3 shows the soil to be clean by the TEM results, but do the PLM results agree?

The data for Fraction 03 for post-demolition AACM soil and post-excavation AACM soil do indicate a difference in the average asbestos content by PLM visual estimation: 0.87% for the former vs 0.32% for the latter. (The “<1” values were changed to 0.01 for this calculation.) However, the distributions overlap. In a practical sense, could two inches of depth be expected to have much effect on samples of soil that has been run over by a tracked vehicle?

7.7 Secondary Objective 8 – Table 7-19 does not include samples during pre-wetting of the AACM building because none were taken. Using data from Table A-9, a comparison of the samples during demolition only (without the walkers) affirms that the exposure during the AACM demolition (mean = 0.0098 f/cm³; 95% UCL = 0.0180 f/cm³) is much less than during the NESHAP demolition (mean = 0.0351 f/cm³; 95% UCL = 0.0781 f/cm³). Considering that a wet demolition is being compared to a dry one, this should surprise no one.

The abatement samples should not be included in the comparison. In Table A-10, the “ND” entries for the NESHAP abatement are <0.0017 f/cm³ and <0.0032 f/cm³ with both equal to the limit of detection. Excluding the sample for Worker 5 (<0.0032 f/cm³) because of its very short duration (possibly a pump failure) gives a mean concentration of 0.0621 f/cm³ and a 95% UCL of 0.1424 f/cm³. Although comparison to the OSHA PEL is not an objective, this result suggests that the wallboard may not have been “adequately wet” before removal.

The duration of sampling is unclear. For the NESHAP abatement, an 8 to 10 hr work shift is mentioned in 4.1.1.3.1 and the flow rate for personal samples is given in 5.1.2 as “either one or two liters per minute. An air volume of approximately 480 to 960 liters was targeted for these samples.” The data in Table A-10 suggest that the samples were taken during a 10-hr work day. Because these workers had exposure for an entire 8-hr shift and then some, there is no “zero exposure time” by which to adjust their exposure. Based on the sample volumes, ASB-2, 3, 4 and 6 were apparently taken at 2 lpm and ASB-1 at 1 lpm; the 60-L ASB-5 could have been either and probably represents a pump failure. It is unclear from Table A-9 whether the AACM demolition took twice as long as the NESHAP demolition or whether the former samples were taken at 2 lpm and the latter at 1 lpm.

Although “All field blanks had non-detected asbestos concentrations at <7 s/mm,” (9.3.1.2) there is no record of blanks for the personal samples taken for worker monitoring having been analyzed by PCM as required by 29 CFR 1926.1101 Appendix A or by NIOSH Method 7400.

The personal sample results have implications for respiratory protection requirements under OSHA's revisions to 29 CFR 1926.1101(h)(3)(iv) on August 24, 2006 . Demolition of a building with asbestos-containing wallboard is OSHA Class II work. It is Class I if friable materials such as “popcorn ceilings” are left in the building as contemplated in Exhibit 1, Table 1. In the latter case, the OSH A standard would require the demolition workers to use powered air-purifying respirators until exposure monitoring showed that the PELs were not likely to be exceeded.

SECTION 8 COST COMPARISON – This section documents substantial savings for the AACM demolition over the NESHAP abatement and demolition. These savings were realized with the demolition contractor working under intensive scrutiny by EPA and their designees in the context of a research project. Absent such oversight and with the emphasis on productivity and cost control common to a competitive bidding environment, further savings could undoubtedly be achieved.

The costs in Table 8-1 are well-documented in the text and mostly reflect actual or pro-rated charges. I do not challenge them insofar as they pertain to this specific demonstration . Table 8-2, however, presents my estimate of what it would cost to demolish the AACM building under “real world” conditions.

This table breaks out costs for an owner's representative and a demolition contractor. The Draft Report emphasizes the demolition aspects of taking down the AACM building while down-playing the fact that this work includes removal of ACM from the building and its disposal, making the job an abatement project subject to not only EPA but OSHA and state regulations. Most states that regulate asbestos abatement will require that it be done under the cognizance of an owner's representative independent of the demolition contractor and that plans and specifications be prepared for the work. Some may require the work to be done by a licensed asbestos abatement contractor, an assumption that Table 8-2 does not make. Participation by an owner's representative in the capacity of a consultant and project monitor is required by ASTM E1368 Standard Practice for Visual Inspection of Asbestos Abatement Projects as well as the National Institute of Building Sciences Asbestos Abatement and Management in Buildings: Model Guide Specification.

Pre-demolition
The NESHAP does not define a “thorough inspection” before a renovation or demolition. The industry standard for such an inspection is not an “AHERA survey” but a Project Design Survey according to ASTM E2356 Standard Practice for Comprehensive Building Asbestos Surveys. The cost of this survey in Table 8-2 has been increased to $3,000 to allow for collection of information to prepare the plans and specifications in addition to collecting and analyzing bulk samples.

If and only if the Project Design Survey determines that no ACM needs to be removed by an abatement contractor and an accredited project designer so attests (which could be challenged and subject him to a citation and other liabilities) should demolition by the AACM proceed.

Plans and specifications need to be prepared by the accredited project designer because ACM will be disturbed and removed in the course of demolishing the building. The procedures for pre-wetting the ACM, wetting it during demolition, loading the trucks, disposal at the landfill and all associated clean-up must be described. The cost of preparing the plans and specifications is reduced from the NESHAP figure to $3,500 in recognition that certain activities and requirements for conventional abatement need not be described.

Site mobilization by the contractor has been increased to $5,000 to allow for construction and operation of decontamination facilities for personnel.

OSHA would consider this Class II work under 29CFR1926.1101 and require that the workers receive 8 hours of training and the supervisors an additional 4 hours. This training can be provided by the owner's on-site representative (project monitor), for which a daily rate of $400 reflects the absence of air monitoring services on days while training is being conducted. The contractor's labor rates for 14 workers and two supervisors approximate the $45/hr average in paragraph 8.2.5. The demolition crew will need to be fit-tested for respirators and there are other costs to the employer such as medical examinations and training associated with a respiratory protection program.

Building Demolition
Coverage by two on-site project monitors for the first three days of demolition, including air monitoring for the owner's purposes, is shown. This would not be nearly as extensive as during the demonstration and analysis of samples by PCM would be expected. Coverage by one project monitor during excavation on the fourth day is shown.

The contractor's costs are taken for excavation, labor and wetting surfactant directly from Table 8-1. OSHA compliance monitoring is reduced to $1,000 by eliminating lead – assuming the contractor actually gets it done by a third party (not the project monitor). As it is unlikely the local fire company will send a foaming truck, $1,000 is shown to rent this equipment. The necessary equipment for conductivity testing will have to be rented and this cost is shown as $500.

Construction Debris T&D
One day of project monitor oversight and final close-out documentation are the only costs for the owner's representative, shown as $500 each. The costs for the contractor are taken directly from Table 8-1. Not to dispute that the contractor spent $7,078 on scaffolding during the demonstration for lining the trucks, I question whether they would go to that effort and expense were they not under the watchful eye of the federal government.

Summary of costs
The total cost for the owner's representative is $10,600 and for the contractor is $63,909, for an overall total of $74,509. Instead of the $50,967 (47%) difference between the NESHAP and AACM costs in Table 8-1, the difference in Table 8-2 is $33,822 (31%). The 4,500 ft² floor space is not necessarily the most appropriate basis for calculating unit costs: they could also be figured on the basis of the 20,700 ft² of wallboard or the combined 4,244 ft² of floor tile and linoleum.

Other costs
Two costs of potentially major significance are not shown in either table. It may be necessary, for community relations purposes if no other reason, to temporarily re-locate occupants of buildings in the vicinity of the one(s) being demolished. The size of such a “buffer zone” will depend on many intangibles and affect the costs accordingly. Business interruption and temporary lodging of residents are two of the costs. Also, it may be necessary (or at least prudent) to cover buildings with plastic as shown in Figure 4-16, and to inspect the buildings after the demolition is complete, in a manner that will convince occupants it is “safe” to move back in.

This section concludes by recognizing the competitive factors in the construction industry – including abatement and demolition – that could drive the costs for either approach up or down. A major cost that is not shown as a direct expense in either table is the contractor's general liability insurance. Unless the firm is regularly engaged in asbestos abatement as well as demolition, its insurance will exclude the work required by the AACM. Firms without asbestos coverage, which the owner would be foolish not to require, would not bid and the pool of potential contractors would be reduced.

CONCLUSIONS

The demonstration project did not provide conclusive evidence that the AACM is comparable to current NESHAP methods insofar as the most important metric of airborne fiber concentrations is concerned; in fact, the statistical analysis shows it to be slightly inferior. A major deficiency was the failure to compare fiber concentrations during the demolitions to previously-measured background levels or to prevailing urban concentrations.

To achieve even this level of fiber control required using a foaming method that is beyond the capabilities or inclinations of the contractors who would be doing this work. The “cost savings” are substantially reduced when the expense of adequate preparation, oversight and training are considered.

If anything, the demonstration showed that leaving asbestos flooring materials in a building while it is demolished is not advisable, as high concentrations of debris were found in the soil after the both buildings were demolished. The extent to which the presence of these materials in both buildings affected the airborne fiber levels on which the primary objectives depended cannot be known.

Prepared by:

Andrew F. Oberta, MPH, CIH
The Environmental Consultancy
107 Route 620 South, Suite 102 , MS 35E, Austin , TX 78734
www.asbestosguru-oberta.com
(512) 266-1368

Mr. Oberta has over 25 years of experience as an asbestos consultant. His work has been internationally-recognized and extensively published and presented. He chairs the ASTM Task Group on Asbestos Management and is the author of the ASTM Manual on Asbestos Control: Surveys, Removal and Management.