Document 5b3JvGnyYgJawO34kpnxyboVD

FILE NAME Household Contact HC DATE 2015 DOC HC065 DOCUMENT DESCRIPTION Journal Article - Airborne Asbestos Home Exposures During Handling of Contaminated Clothing Following Simulated Full Shift Workplace Exposures Journal of Exposure Science and Environmental Epidemiology 2015 15 @ 2015 Nature America Inc. All rights reserved 1559-0631 www.nature.com/jes ORIGINAL ARTICLE Airborne asbestos home exposures during handling of contaminated clothing following simulated full shift workplace exposures Jennifer Sahmel Christy A. Barlow Shannon GaffneyHeather J. Avens Amy K. MadlJohn Henshaw Ken Unice David GalbraithGretchen DeRoseRichard J. Lee Drew Van Orden Matthew Sanchez Matthew Zock and Dennis J. Paustenbach The potential for occupational domestic or home exposures from contaminated work clothing has been acknowledged for decades but historically has not been quantitatively well characterized A simulation study was performed to measure airborne chrysotile concentrations associated with laundering of contaminated clothing worn during a full shift work day Work clothing fitted onto mannequins was exposed for 6.5 h to an airborne concentration of 11.4 cc PCME of chrysotile asbestos and was subsequently handled and shaken Mean min and min concentrations during active clothes handling and shake were 3.2 and 2.9 cc respectively PCME Mean airborne PCME concentrations decreased by 55 15 min after clothes handling ceased and by 85 after 30 min PCM concentrations during clothes handling were 11-47 11-47 11-47 greater than PCME concentrations Consistent with previously published data daily mean h TWA airborne concentrations for handling activity were approximately 1.0 of workplace concentrations Similarly weekly 40 TWAS for clothes handling were approximately 0.20 of workplace concentrations Estimated home cumulative exposure estimates for weekly clothes handling over year working durations were below 1 year for handling work clothes contaminated in an occupational environment with full shift airborne chrysotile concentrations of up to 9f cc h TWA Journal of Exposure Science and Environmental Epidemiology advance online publication 29 April 2015 jes.2015.15 Keywords asbestos domestic exposure exposure assessment inhalation exposure occupational exposure home exposure INTRODUCTION Previously published studies and reviews related to asbestos and home exposures have primarily explored the association between disease incidence and the reported potential for household or occupational exposure Beginning in 1976 a number of epidemiological studies reported on the risk for developing pleural mesothelioma in the household contacts of asbestos workers.14,9-13 Some studies have also noted that cases of disease in the household contacts of asbestos workers occurred more commonly in certain professions such as insulation workers and miners as well as some asbestos product manufacturing and shipyard workers.2.3.5.8-10 When studies have reported the asbestos mineral fiber type associated with disease in household contacts authors have specifically cited exposure of the workers to amositc 4,13 crocidolite or general amphibole and chrysotile exposure It is notable that there is a large body of evidence in the published literature supporting substantial differences in fiber potency according to asbestos mineral type with chrysotile being the least potent of the common industrial mineral types for lung cancer and mesothelioma and the amphiboles including both amosite and crocidolite being far more potent The accumulated evidence to date points to the potential for increased risk of disease in household populations with home exposure above some cumulative lifetime exposures to amphiboles or mixed asbestos fiber types World asbestos production data have shown that the use of amphibole asbestos began to decline in the 1970s and ceased in the 1990s whereas chrysotile production did not begin to decrease until the 1990s.19,20 Owing to the marked differences in potency epidemiological study results of home exposures to amphboles or mixed fibers are not relevant to populations exposed to predominantly or only chrysotile Additionally the epidemiology studies on home exposure generally involved persons who historically worked in industries with asbestos exposure beginning in the 1930s and 1940s through the 1970s or 1980s.913,22,23 Few studies have addressed the magnitude of airborne asbestos concentrations in the home environment associated with take- home contamination potential from the workplace The National Institute for Occupational Safety and Health NIOSH and others have examined available indirect evidence of the asbestos take- home exposures of household members using such methods as questionnaire responses evidence from medical evaluations and reports of possible sources of asbestos exposure in the home NIOSH highlighted laundering of the contaminated Chem ,,CardnoChemRisk Boulder Colorado USA Cardno ChemRisk San Francisco California USA Cardno Aliso Viejo California USA Cardno ChemRisk Sanibel Florida USA Cardno ChemRisk Pittsburgh Pennsylvania USA RJ Lee Group Monroeville Pennsylvania USA and Cardno ChemRisk Jackson Wyoming USA Correspondence Jennifer Sahmel Cardno ChemRisk 4840 Pearl East Circle Suite 300W Boulder 80305 CO USA Tel 11 303 906 7025. Fax 11 303 417 1066 E mail Jennifer Sahmel@cardno.com Sahmel@cardno.com Received 11 July 2014 revised 23 December 2014 accepted 3 February 2015 home exposure potential from full shift exposures Sahmel et al 2 clothing of workers as a primary exposure route for asbestos brought home by workers Correspondingly the current investigation focused on characterizing airborne concentrations during the handling of contaminated clothing consistent with laundering activities A handful of studies from the 1970s and 1980s reported airborne fiber concentrations associated with the presence or handling of contaminated clothing Of these Sawyer and Mangold reported sampling results using the phase contrast microscopy PCM analytical method which because of its low cost and ease of use in the field was the analytical method commonly used for regulatory purposes to estimate airborne asbestos concentrations However the PCM sampling and analytical method is not specific to asbestos fibers and therefore will not necessarily be an accurate metric for asbestos exposure potential when asbestos fibers are present e.g. fibers from work clothing A third study carried out by Nicholson et al reported air sampling results based on gravimetric analysis in nanograms of asbestos per cubic meter of air m a method that does not allow for a direct comparison with fiber counts per average 1.2 of the h TWA simulated work environment concentrations When converted to 40 TWAS consistent with once weekly laundering of a week's worth of work clothing chrysotile concentrations during min active clothes handling were found to average 0.25 of the weekly airborne concentra- tions to which workers were exposed The purpose of this follow study was to further evaluate the relationship between the handling of work clothing during laundry activities home exposure potential and the occupational airborne exposure of the worker Like the initial study this study evaluated scenarios in which the clothing was handled and shaken indoors Historically workers may have blown or brushed off clothing in the workplace or shaken it outdoors before bringinigt into the home thus actual exposures of clothes handlers may have been lower than what was measured in our study in certain scenarios This study also investigated in more detail some of the potentially important exposure factors that could affect indoor airborne chrysotile concentrations during clothes handling Specifically the current study ) simulated a concentration of chrysotile that was many fold higher than what volume of air without a conversion factor which is likely to vary with each workplace Owing to the sampling and analytical methods used in these three historic studies none of their results can be used to provide an accurate range of the airborne asbestos fiber concentrations associated with handling of contaminated work clothing Several more recent exposure studies have been published that evaluated the simulated handling of contaminated work clothing following automotive work activities using both PCM and transmission electron microscopy TEM which is a specific analytical method for determining asbestos mineral fiber types29-32 In these studies the reported airborne concentrations of asbestos during work activities associated with friction products were very low or detectable ND and the airborne asbestos concentrations during clothes handling when detectable were even lower.29-32 Although these data are informative for the specific tasks evaluated they have unknown relevance to the handling of clothing that is more heavily contaminated with asbestos fibers or for activities in which the worker exposures were to friable asbestos products or raw asbestos fibers Further these studies do not present a basis to quantitatively characterize the relationship between workplace exposures and the exposure potential associated with handling contaminated work clothing in the home To address the identified gaps in the available data an initial study was designed and conducted to compare asbestos exposures at selected simulated workplace concentrations with the corresponding concentrations generated during contaminated clothes handling and shake SO Chrysotile asbestos grade 7T was used in that study because of its use in many industrial and consumer products e.g. brakes roofing materials floor tiles gaskets packing and because data indicated that chrysotile asbestos continued to be used in these products after amphibole asbestos use declined substantially As a result the potential for home exposure to chrysotile was likely to have occurred more frequently and more recently compared with home exposures to amphiboles In the initial study described in Sahmel et 28 clothing was fitted on mannequins in a sealed chamber and exposed to target airborne chrysotile concentrations over periods of 30-45 min to concentrations of up to 3.3f cc or 0.55 cc as an h weighted average TWA In six subsequent individual handling events the clothing was then handled and shaken out for min to simulate laundry activities in the home For direct comparison with the simulated workplace concentrations in the initial study h TWA handling concentrations consistent with daily clothes handling and shaking out for min active daily clothes handling were calculated and found to was measured in the initial study and involved work clothing exposed over a full simulated work day ii utilized a lower indoor dilution ventilation rate to more closely approximate the natural room ventilation rate within a typical residence and iii evaluated the potential influence of work clothing made from different types of fabric i.e. cotton or polyester blend as well as both used and new clothing And finally estimated cumulative exposures of the clothes handler were compared with the estimated cumulative worker exposures For retrospective exposure assessment purposes often the only available information for estimating clothes handler exposure potential for a specific scenario is the corresponding worker exposure both in terms of h TWAs and overall cumulative exposure and so it is informative to compare daily weekly and total cumulative exposures for the simulated worker to the corresponding exposures of the clothes handler The data generated should help to further inform the scientific understanding of asbestos exposure potential during the handling of contaminated work clothing for the conditions evaluated METHODS Study Preparation and Study Setting An institutional review board IRB reviewed and approved the study design prior to commencement Copernicus Group Study ID CRI1-11-208 Durham NC USA The study was conducted in a negative pressure chamber volume of m at RJ Lee Group in Monroeville PA USA that was equipped with an airlock for entering and exiting the chamber after following proper decontamination procedures The chamber was con structed of conductive painted plywood to minimize interaction with airborne fibers or particulates Safety and clearance sampling procedures as well as isolation decontamination and personnel safety procedures have been described previously During all study events a high efficiency particulate air HEPA ventilation air filtration device AFD was operated at a rate of 5 air changes per hour ACH This rate is consistent with the average U.S. EPA reported rate of the naturally driven minimum room to room airflow within residential buildings as presented in the U.S EPA's indoor air quality monitoring program RISK Version 1.5 which is designed to estimate individual exposure to indoor air pollutants.33 Between study events a separate AFD was run at a rate of approximately 24 ACH to decontaminate the chamber and decrease the time to background concentrations During the 5 days of testing which occurred from April 9 to 13 2012 ambient outdoor temperatures ranged from 16.7 62.1 F to 24.3 75.7 while temperatures within the study chamber ranged from 18.5 653 to 23.6 74.5 F during testing Ambient humidity levels outside the chamber ranged from 21 % to 43.1 while levels inside the study chamber were found to be 254 % to 53.6 Details about the grade 7T 7T chrysotile fibers used have been previously described Three types of clothing were utilized new 100 cotton new Journal of Exposure Science and Environmental Fpidemiology Fpidemiology 2015 1-15 '2015 Nature America Inc. HEPA AFD used during decon and clearance -24 ACH HEPA AFD used during study events 3 5 ACH { mannequin + f 47 Figure 1. Chamber design for clothes loading events simulated workplace environment for clothing contamination home exposure potential from full shift exposures Sahmel et al HEPA AFD used during decon and clearance -24 ACH HEPA AFD used during study events 3 5 ACH : _ 0Sm . , 21m Y re 18m 21 a \ 7 t Area Sample Location Location Bystander C f Area SampSalmple e Location Bystander B Area Sample Location ByBsytsatnadnedrer 37m upg 3 AiArirllocok ck . Area Sample Location Bystander D Figure 2. Chamber design for handling and SO events simulated household environment cotton blend of 35 cotton polyester and used 100 cotton For consistency the new uniforms were purchased from the same vendor as the initial study Banner Uniform Center San Francisco CA USA Both new and used cotton work clothing were of a similar work uniform style The used clothing was obtained from a variety of sources and was selected to match the style of the new clothing as closely as possible Human hair wigs were also placed on the mannequins during loading events to characterize the additional exposure potential from contaminated hair after working in an environment with airborne asbestos Loading Events Simulated Workplace Environment For the two replicate loading events an airborne chrysotile concentration of 10f was targeted The chrysotile was aerosolized in the chamber using a dust generation system as previously described with fans running to assist in airborne mixing For each clothes loading event in the chamber nine dressed mannequins three mannequins for each of the three clothing types were placed in a circular pattern at a distance of 1.52.5 meters from the dust generator at the center of the chamber A fresh set of clothing was placed on each mannequin prior to each loading event Figure 1 illustrates the layout of the study chamber during the loading events Exposures to the simulated workers i.e. dressed mannequins were estimated by placing sampling cassettes on the right and left lapels of each mannequin at breathing zone height 1.5 meters during the loading events To avoid overloading the sample cassette filters during the generation of a high concentration of airborne fibers consecutive samples were collected for 75 min or less over a total of 6.5 to simulate the typical exposure duration in an h workday No study participants entered the chamber during loading events and the sampling pumps were turned on and off remotely Following each loading event clothing was carefully removed from the mannequins in order to avold disrupting settled fibers placed in three conductive storage boxes one box for each of the three clothing types and stored for later use in the handling and 50 events Handling and SO Events Simulated Household Environment Six handling and SQ events were performed using the work clothing contaminated during the two simulated workplace loading events Two separate handling and SO events were conducted for each of the three clothing types Three pants sets of clothing of the same fabric type were handled in two separate handling events matched to the corresponding loading event This design allowed for the direct comparison of the corresponding workplace vs clotheshandling concentrations by event During each handling and 50 event personal samples were collected on the right and left lapels of the clothes handler and area samples representing bystanders BYST were collected at distances of 1.8-3.7 meters from the handling activities A diagram of the handling and SO event layout is shown in Figure 2 Each handling and SO event consisted of min of active clothes handling followed by a period of no activity for an additional 30 min for a total of 45 min per event The additional sampling time following clothes handling activities allowed for the measurement of potential residual exposure to the clothes handler if he or she stayed in the room following the handling of clothing for an extended period of time performing other activities such as to iron or fold clean laundry A total of six personal samples were collected on the clothes handler during each handling and SO event Specifically one min lapel personal sample and a pair of min right and left lapel personal samples were collected during the active clotheshandling period During the subsequent min period of no activity one min sample was collected for the 15-20 min time period one min sample was collected for the 15-30 min period and a final sample was collected during the 30-45 min period during each of the six clotheshandling events Four area samples that were intended to represent bystander exposure were also collected over the entire min period See Figure 3 for a graphical depiction of the sampling timeline for each handling and SO event At the beginning of each handling event the handler removed the contaminated clothing from the conductive storage box and then handled and periodically shook out the contaminated work clothing consistent with typical laundering activities The accompanying contaminated human hair wigs associated with the exposed mannequins work clothing were also shaken out during each handling event During the min period of inactivity following active clothes handling clothes handlers did not physically contact the clothing but remained in the chamber so that the residual exposure potential associated with the laundry area after clothes handling could be evaluated Sampling and Analytical Methods Air samples were collected and analyzed in accordance with NIOSH 7400 PCM and NIOSH 7402 TEM PCME concentrations i.e. asbestos fibers ...m in length and 0.25...min width with a 3-1 aspect ratio were calculated by multiplying the ratio of asbestos fibers to asbestos fibers as measured by TEM by the measured PCM concentration for each sample as described in NIOSH method 7402. Area and simulated personal breathing zone air samples including on mannequin lapels during the loading events BYST samples during handling events ambient and background samples and AFD exhaust samples were collected with stationary volume sampling pumps Emerson Pennsylvania USA at a rate of 5.5-20 liters per minute min Personal samples of the clothes handlers study participants working outside the chamber and '2015 Nature America Inc Journal of Exposure Science and Environmental Epidemiology 2015 1-15 . home exposure potential from full shift exposures Sahmel et al 4 Activity Activity Activity Activity Activity df 07 07 Clothes Handlung and Shake A YO 15 On No Actary Post Shake Actary AL 30 must 45 un Sampling Sampling Sampling Air Air Air SO 0-5 mun PSO 15-20 m SQ 0-15 wa rr Sa rrr Fn a PSO 15-30 mu BYST 0-45 min ~ Soon weet PSO 30-45 mu eT SSS SSS i wd Figure 3. Study sample timeline and nomenclature during handling and shake events This figure shows the relative time duration and nomenclature of ) personal samples taken during clothes handling and shake SO 2 personal samples taken post shake PSO and 3 samples collected at bystander BYST locations samples of study personnel during decontamination activities were collected using personal volume sampling pumps SKC Pennsylvania USA at a rate of 1-2 min A minimum of two field blanks was collected during each study event All samples were analyzed by the RJ Lee Group in Monroeville accredited by the American Industrial Hygiene Association Laboratory Accreditation Program 100364 Data and Statistical Analysis Descriptive statistics were performed on the PCM TEM and calculated PCME results of airborne fiber concentrations collected during the loading and SO events Arithmetic means and standard deviations SD were calculated for each type of sample and analytical method along with standard error of the mean SE when appropriate Systat 11 Systat Software San Jose CA USA was used to perform all statistical tests factor analysis of variance ANOVA was used to evaluate the effects of differences in sampling period and measurement method Likewise factor ANOVA was used to evaluate the effects of differences in sampling period and fabric type To perform wise comparisons between different sampling periods or sampling conditions tests were used with the Bonferroni adjustment to account for multiple comparisons For the left and right lapel samples collected during each 15 min handling period the paired results were averaged together and treated as a single sample for further calculations and analyses The sampling results have been presented primarily in PCME however PCM data are also presented for comparison to the PCME values in order to explore the differences between total airborne fibers and airborne chrysotile fibers Calculation of Cumulative Home Exposure Estimates Associated with Specific Workplace Concentrations In the workplace cumulative lifetime exposure to asbestos is often expressed as the average h TWA airborne concentration in units of cc multiplied by the number of occupational years of exposure years or by the number of hours of exposure hours For example the cumulative asbestos exposure of a worker with an h TWA workplace concentration equal to the current asbestos OSHA PEL of 01 fiber for 40-45 years is between 40 and 4.5 years or between 8000 and 9,000 / cc assuming 2000 h worked per year Cumulative exposure or dose can be defined in terms of different metrics including cumulative workplace exposure and cumulative environmental exposure e.g. occupational or ambient air exposures Cumulative occupational exposures are often used when attempting to characterize the plausible lifetime cancer risk for asbestos because this metric can be most readily compared with dose-response information developed from epidemiology studies of workers who encountered asbestos -36 When estimating the incremental cancer risk associated with a lifetime of exposure to a carcinogenic agent an occupational year is defined differently than an environmental or occupational year As stated above an occupational year is typically defined as 250 days for 8h day or 2000 year In contrast an environmental ambient year or calendar year is often defined as 24 day for 365 days or 8760 year As the asbestos epidemiology literature is typically presented in terms of year of exposure based on a 40h work week one must convert the environ- mental cumulative exposure to an equivalent workplace cumulative exposure in order to be able to estimate the lifetime risk using available epidemiological data Using units of cc rather than years allows for a direct comparison of cumulative exposure between the workplace ambient exposure and the exposure scenario of interest if term average inhalation rates are taken to be relatively similar between scenarios An analysis of the association between the simulated workplace exposures and handling exposures measured in this study and the initial study was used to estimate cumulative exposure potential over the range of specific workplace concentrations evaluated. RESULTS A total of eight separate exposure events were conducted two loading events and six handling and SO events For all study events samples resulted in measureable concentrations i.e. there were no samples that were ND for asbestos Personal sampling was also conducted outside the study chamber to monitor participant safety during the study Sample results demonstrated that personal airborne fiber concentrations for study participants outside the study chamber were /0.002 /0.00c2 c PCM Inside the chamber during decontamination activities personal exposures collected on the outside of PPE and without regard to respiratory protection were /0.03PCME Outdoor background concentrations were /0.00c3c PCM for the duration of the study Chamber clearance samples prior to handling events and samples collected at the AFD exhaust points were /0.003 /0.00c 3 c PCM Airborne Fiber Concentration Measurements During the Loading Events Simulated Workplace Environment Each loading event lasted approximately 6.5 h 386 and 388 min Figure 4 shows the overall distribution of the PCM and PCME air concentration results for both events arithmetic mean quartiles fifth and ninety percentiles The mean of the PCME airborne loading concentrations for chrysotile was 11.4f cc 11.1 cc and 11.7 cc for Loading Events # and 2 respectively The mean PCM airborne concentration was 11.6f cc 11.4f cc and 11.8 cc respectively Supplementary Table A provides the sample numbers = 15-18 sample durations 57-73 min each arithmetic means and Ds for PCM TEM and PCME results for each loading event Airborne Fiber Concentrations During and After Indoor Clothes Handling and SO Simulated Household Environment Figure 5 visually depicts an exemplar handling and SO event PCM and PCME airborne fiber concentrations were measured during each active handling and 50 sampling Journal of Exposure Science and Environmental Epidemiology 2015 1-15 '2015 Nature America Inc. home exposure potential from full shift exposures Sahmel et al 5 period SO 0-5 min and SO 0-15 min during each shake out PSO sampling period PSO 15 2m0in PSO 15-30 min and PSO 30-45 min and at area BYST locations during the combined SO and PSO periods BYST 0-45 min Figure 6 Mean PCME airborne fiber concentrations were 3.2 cc for SO 0-5 min and 2.9 cc for SO 0-15 min As noted above the right and left lapel 50 0-15 samples for each of the six handling events were averaged together and treated as a single sample consistent with standard industrial hygiene sample analysis Paired tests for the PCM TEM and PCME results indicated that concentration differences between the right and left SO 0-15 min samples were not statistically significant >> 0.05 Airborne concentrations decreased during the clothes handling and SO period PSO compared with the active handling and SO period similar decreases in fiber concentrations were observed for both the PCM and PCME measurements with approximately a 50 decrease in fiber concentrations during the first 15 min PSO to 1.31 cc PCME a decrease of 49 for PCM and 55 for PCME A total decrease of over 80 was observed from active SO to the second 15 min PSO with a reduction in the airborne concentration to 0.45 cc PCME decrease of 82 for PCM and 85 for PCME ) 16 cc f Concentration 14 | Concentration Concentration 12 Concentration Concentration Concentration 4 Fiber Fiber 00 Airborne Airborne Airborne Airborne 50 PCM N 15 . PCME N 15 Loading Event 1 PCM N 18 PCME N 15 Loading 2 Figure 4. Distribution of the PCM and PCME airborne concentrations for the loading simulated workplace events This figure shows the comparative median quartiles fifth percentile and ninety percentile values box plots and means black circles for the loading events # and 2 All samples were detected above the limit of detection LOD In cases where N < 18 the remaining samples were overloaded and not analyzed during the PSO 30-45 min period The mean PCM and PCME concentrations during the second half of the PSO sampling period PSO 30-45 min were statistically significantly lower than during the active handling period SO 0-15 min test Bonferroni = 0.05 Within each of the handling sampling periods the mean PCM concentration was higher than the mean PCME concentra- tion A factor ANOVA conducted to evaluate the effect of sampling period and measurement method i.e. PCM vs PCME on the measured fiber concentrations indicated that the order of the sampling periods significantly impacted the measured concentra tions as did the analytical method i.e. PCM vs PCME = 0.05 Depending on the sampling period the PCME results were % to 32 lower than the PCM results with the smallest difference seen for the BYST samples These results indicated that a statistically significant fraction of the airborne fibers meeting the PCM counting criteria were likely fabric fibers Additionally both the PCM and PCME concentrations measured during the first 5 min of clothes handling and SO were virtually the same as concentrations measured during the entire 15 min of clothes handling and SO This finding suggested that airborne fiber concentrations remained relatively steady between the 5 to min active handling period Supplementary Table B reports the sample numbers arithmetic means and SDs for the PCM TEM and PCME mea- surements taken during each of the handling events for all sampling time periods during and after clothes handling Personal vs BYST Exposures During and After Indoor Clothes Handling and SO Simulated Household Environment To evaluate the potential for exposure to bystanders during the handling events area samples were collected at 18 meters n per event 2.1 meters = per event and 3.7 meters = per event from the clothes handler BYST samples were collected throughout each min handling and SO event period which did not allow for a direct comparison with the active personal clothes handler measurements Therefore to compare the personal and BYST samples the clothes handler exposure during the full min period was calculated by averaging the PCME results for the three min time periods SO 0-15 min PSO 15-30 min and PSO 30-45 min with equal weighting for each min time period The arithmetic mean calculated personal PCME concentration for the clothes handler during this min period was 1.57 cc whereas the mean measured PCME concentration at the BYST locations was 0.63 cc range 0.61-0.65 cc Figure 7 No trend was observed among the BYST concentrations with increasing distance from the clothes handler up to a distance of 3.7 However analysis of this Figure 5. Photos depicting clothes handling and shake out '2015 Nature America Inc. Journal of Exposure Science and Environmental Epidemiology 2015 1 15 home exposure potential from full shift exposures Sahmel et al 6 cc f Concentration Concentration 4.0 Concentration 3.0 Concentration Concentration Concentration Concentration 20 Concentration Airborne Airborne Airborne 1.0 4 Airborne Airborne 80 ; So 0-5 min 0-15 min N N Active Clothes Handling Shake Out 1 PSO 15-20 min 15-30 min PSO 30-45 min ; N N N Post Shake Out No Activity 1 BYST i 0-45 min i 24 Bystander Locations | Sampling Period Figure 6. PCM and PCME mean airborne fiber concentrations measured during clothes handling and SO post shake PSO and at BYST locations This figure presents the PCM grey and PCME black average airborne fiber concentrations measured during handling and SO events Letters and notations below the figure indicate the sampling periods for which the mean concentration was statistically significantly lower signified by the symbol < compared with other sampling periods test Bonferroni a = 0.05 All samples were detected above the LOD Error bars indicate SE PCME PSO 15-30 min 0-5 min PCM PSO 30-45 min 0-5 min and SO 0--15 min PCME PSO 30-45 min 0-5 min and SO 0-15 min PCM BYST 0-45 min 0 m5in SO 0-15 min and PSO 15-20 min PCME BYST 0- 45 min 0-5 min and SO 0-15 min comparison was limited because of the continuous sampling at all BYST locations across both the active and inactive clothes- handling periods that did not allow for a direct ratio of concentrations at distance by activity For the exposure conditions used in this study chamber volume of m ventilation rate of 3.5 ACH chrysotile concentrations at the BYST locations 1.83.7 m from the source were just below 50 of the concentrations measured in the personal breathing zone of the clothes handler Effect of Fabric Type on Exposure Potential During Clothes Handling and SO For the six handling events two events utilized new cotton fabric clothing two utilized new polyester fabric clothing and two utilized used cotton fabric clothing Figure 8 shows the PCM and PCME concentrations by clothing type associated with the active handling periods for all events SO 0-5 min and SO 0-15 min There were no statistically significant differences observed in PCM or PCME concentrations for the three different fabric types ANOVA 0.05 Additionally no trends were observed between results during the first 5 min of SO as compared with the entire 15 min SO period for any of the fabric types Supplementary Table C provides the sample numbers arithmetic means and standard deviations for the PCM TEM and PCME measurements taken during active clothes handling for each fabric type Comparison Between Loading Events Simulated Workplace Environment and Handling Events Simulated Household Environment To facilitate a comparison between the loading simulated workplace environment and handling simulated house- hold environment PCME concentrations TWA airborne concen- trations were calculated for each simulated workplace event and handling event to evaluate the relative household exposures associated with specific workplace exposures For direct comparison with the h workplace TWA measurements h handling TWA concentrations were calculated representing the measured exposure potential associated with daily washing of three sets of contaminated work clothing compared with the daily 8 TWA in the workplace Forty TWA clotheshandling concentrations were also calculated to account for the fact that for household washing contaminated clothing for a single worker multiple sets of contaminated work clothes would more likely be laundered together approximately once per week For both the simulated workplace and simulated handling events the TWA values were calculated assuming that clothes- handling asbestos exposure did not occur for the remaining period of time outside of the min duration of the active clothes handling and staying in the laundry room after clothes handling and for which no data were obtained in this study The arithmetic mean of the calculated PCME h TWA values was 9.2 for the simulated workplace exposure events loading and the 40 TWA was also 9.2 cc PCME assuming the same consistent concentration in the workplace over the day work week The mean handling PCME h TWA concentrations were 0.033 cc 5 min and 0.092 cc 15 min for active clothing SO The mean calculated PCME h TWA values associated with 15 min of daily active clothes handling SO 0- 15 min were therefore 1.0 of the simulated workplace h TWA This compared with a value of 1.2 for the initial study which loading involved lower concentrations of up to 0.55 cc as an 8 h TWA TEM Table .28 For BYST exposure potential the mean calculated BYST PCME 8 TWA during the 15 min of daily clothes handling and subsequent 30 min of inactivity was an average of 0.6 range 0.3 1.o3f the PCME h TWA for the simulated workplace Additionally 40 TWA or weekly percentage ratios for clothes handling were calculated by dividing the 40 handling TWA concentrations by the 40 workplace TWA concentration Table 2 The 40 workplace TWA concentration is the same as the 8 workplace TWA concentration as it was assumed that workplace exposures were consistent from day to day For the 40 handling TWAS it was assumed that either one or Journal of Exposure Science and Environmental Epidemiology 2015 1-15 '2015 Nature America Inc home exposure potential from full shift exposures Sahmel et al 7 2.5 PCME 2.0 + 1.5 Concetraion cc 1.0 4 Personal vs. Bystander PCME 15 min active shake i + 30 min inactivity shake n a b 0.5 Airbone 0.0 | : 0m moe 1.8 | 2.1 Z se 3.7 N 6 N 6 N 12 N Personal Exposure ' Bystander Exposure Measured Calculated Figure 7. Comparison of mean PCME concentrations associated with personal vs BYST exposures during handling events Area samples to estimate BYST exposure potential were collected during each min handling event sampling period As no single personal sample spanned the entire 45 min personal concentrations for each event were calculated from the 15 min sampling periods as follows 1/3 0-15 PSO 15-30 PSO 30-45 min The mean min calculated personal handling exposure was 1.57 cc PCME Error bars indicate SE Letters and notations below the figure indicate the datasets for which the arithmetic mean was statistically significantly lower signified by the symbol << compared compared with the mean personal exposure test Bonferroni a = 0.05 Arithmetic mean for BYST 1.8 m away 0.62 cc calculated personal concentration 1.57 cc PCME Arithmetic mean for BYST 2.1 m away 0.61 cc calculated personal concentration 1.57f cc PCME Arithmetic mean for BYST 3.7 away 0.65 cc calculated personal concentration 1.57 cc PCME two loads of work laundry would be handled in a typical household per week three or six sets of work clothing total Two different numbers of clothing sets were evaluated in order to assess the potential effect of the number of sets handled on the airborne concentrations and for comparison with the initial study For active clothes handling the mean handling PCME 40 TWA values ranged from 0.007 5 min to 0.018 cc min The 40 TWA percentage ratio of clothes handling to simulated workplace concentrations for handling clothing for min once per week averaged 0.20 in the current study compared with 0.25 in the initial study Table 2 The mean calculated PCME 40 TWA for BYSTS over the 15 min of clothes handling and subsequent 30 min of inactivity was 0.13 of the simulated workplace concentration 0.012 cc for BYSTS vs 9.1/8 cc for the simulated workplace Results indicated that the TWA ratios remained relatively consistent despite differences in average simulated workplace concentrations across the two studies of approximately fold 0.3-9f cc handling duration appeared to be a better predictor of exposure potential than the number of sets of clothing handled based on the combined results of the two studies Measured RT Values for Determining Cumulative Exposure Estimates On the basis of the very consistent results obtained for the workplace concentration ratios over a substantial range of airborne asbestos concentrations it was determined that cumulative exposures associated with handling activities could be estimated for home exposure over a range of airborne concentrations The ratio of the home to occupational airborne concentrations measured over the range of simulated concentrations tested in the two studies was therefore used to develop an approach for conducting cumulative exposure calculations This ratio is referred to as R and is defined as the home based concentration CTH.Sim divided by the 8 TWA occupational or workplace concentration Cocc 8hr that is COLL for handling exposure times ranging from 0.08 to 0.75 h R values for the scenarios examined in the + 2< 015 Nature America Inc. current study are presented in Table 3. These values were very consistent over the breadth of simulated workplace concentrations evaluated in the two studies average was 0.35 +/- 0.04 for active handling activities Using the information presented in Table 3 and the calculated R values the estimated home airborne concentration for a specific task of interest Cmi task can be determined when the h TWA workplace exposure concentration Cocc cc 8hr TWA for the worker bringing home contaminated clothing is known or can be reliably estimated Citask = cc Cocc free 8hr TWA ^ RTH It should be noted that the corresponding airborne concentra- tions for handling times shorter than min were not measured and therefore estimates for handling exposures less than 5 min may not be accurate using the RTH values from this study However according to the airborne handling concentrations presented in Tables 1 and 2 it does appear that the handling exposure potential was consistent between 5 and 15 min allowing for the consideration of exposure estimates for different time durations within this range e DISCUSSION This study quantitatively compared the concentrations of asbestos in a simulated work environment with the corresponding airborne concentrations generated during the subsequent handling of contaminated work clothing for laundering in a household environment The TWA concentrations of airborne chrysotile obtained for the simulated workplace conditions evaluated in this study clothes loading events averaged 9.2f cc as determined by PCME This concentration was consistent with historical airborne fiber concentrations that were observed in many industrial environments in the 1960s The correspond- ing mean of the airborne concentrations associatwietdh active handling of contaminated work clothes in the home between 5 and 15 min was 3.1 cc PCME Airborne chrysotile concentrations declined substantially during the period following the 15 min of active clothes handling from 2.9 to 1.3 cc PCME during the first 15 min of inactivity and then to 0.45 cc PCME during the second min period of inactivity Journal of Exposure Science and Environmental Epidemiology 2015 1-15 home exposure potential from full shift exposures Sahmel et al 8 7.0 - -: a _ we / . T PCM cc 6.0PCME 5.0 + Concetraion Airbone SO 0-5 min SO 0-15 =, min 0-15 min min T i SO | 0-15 min N N N 9, N | N N New Cotton New Polyester Used Cotton Fabric Type and Sampling Period Figure 8. Comparison of airborne PCM and PCME fiber concentrations measured during handling of different clothing fabric types Clothes used in the study were made of new cotton new polyester and used cotton PCM grey and PCME black results are shown for the SO min and SO 0-15 min sampling periods Error bars indicate SE There were no statistically significant differences in PCM or PCME concentrations by clothing fabric type The min active handling value could be considered a maximum plausible concentration associated with clothes handling at the workplace concentrations evaluated as it is unlikely that the duration of handling and SO of contaminated clothes would have typically exceeded min Additionally heavily contaminated laden work clothing may have been brushed off before leaving the workplace or shaken out before bringing it into the household environment rather than the assumed indoor handling scenario used in this study Such activities could result in lower exposure potential to the household member On a TWA basis min handling concentrations equated to either % on a daily basis h TWA or 0.20 on a once per week basis 40 TWA of the measured exposures for the simulated worker The corresponding percentage ratio values from the initial study were 1.2 8 TWA and 0.25 40 TWA Taken together the ratios between handling concentrations and workplace concentrations were extremely consistent between the two studies and showed a trend of increasing airborne chrysotile concentrations during clothes handling with increasing workplace airborne concentrations The combined results of this study and the prior published study demonstrated that either daily or weekly exposures based on an h or 40 TWA airborne concentration for clothes handling were likely to be a small fraction % or below of the corresponding workplace airborne loading concentrations despite a fold range in the simulated average workplace airborne chrysotile concentrations that were evaluated see Table 2 0.3 cc to over 9f PCME h simulated workplace TWA On the basis of the consistency of the measured ratios between workplace and household exposures the results of the study were also used to estimate cumulative exposure potential for takehome scenarios using the R ratio values as presented in Table 3 Examples of the use of RTH to estimate cumulative home exposure for clothes loading in work environments with hypothetical h occupational TWAs of 0.1 1 and 9 cc are shown in Table 4. For the purposes of these examples a handling frequency of 50 weeks and a duration of 25 years were assumed.T3he9 units of hour allowed for a direct comparison of the ambient occupational and home cumulative exposures Corresponding cumulative exposures in year were also presented on both an occupational basis and environmental basis for comparison Table 4 shows that similar estimates of cumulative exposure were derived from the current study and the initial study for various exposure scenarios despite appreciable differences in the loading concentrations between the two studies This result indicated that cumulative exposure potential appeared to be linearly proportionate to workplace loading concentration expressed as an h TWA Table 4 also illustrates the use of our data to reconstruct cumulative exposures for different combina- tions of occupational loading and home scenarios For example 15 min per week of handling clothing that was exposed to a high occupational loading environment of 9f cc as an h TWA corresponded to a home cumulative exposure of 0.45 / year on an occupational year basis The data also indicated that remaining in the room after SO for min would contribute an additional 0.20f year to lifetime cumulative exposure For comparison these cumulative exposure values for the clothes handler are within the range of allowable cumulative lifetime equivalent exposures for workers at the current Occupational Safety and Health Administration OSHA Permissible Exposure Limit PEL and American Conference of Governmental Industrial Hygienists ACGIH Threshold Limit Value TLV of 0.1 cc as an h TWA Over a working lifetime of 45 years daily workplace exposures of 0.1 cc would translate to a theoretical tolerable lifetime equivalent cumulative exposure of 4.5 cc- year Toxicologically and epidemiologically there is as much or more than a fold difference in the potency of the various asbestos fiber types with respect to mesothelioma if chrysotile is potent at 15,21,41,42 Therefore when estimating risk this difference must also be considered as it is currently not addressed in the PEL or TLV for asbestos With respect to residual exposure in a small room with a residential ventilation rate the study results showed that chrysotile fibers in the size range of interest for the regulatory Journal of Exposure Science and Environmental Epidemiology 2015 1-15 '2015 Nature America Inc. calculation calculation calculation calculation TWA h for used used Asumptions As umptions Asumptions Asumptions concentrations concentrations concentrations concentrationsconcentrations conetraions PCME PCME TWA TWA ( average average weighted weighted weighted weighted time time h calculated calculated calculated calculated Mean Mean 1. 1. Table loading simulate in loading 01-0.7 13 01-05 simulate calculations range 04-17 25 100 chrysotile TWA 01-0.7 05-22 chrysotile to calculations Percent 04 chrysotile calculations Percent airborne performed the performed cc ) 0.0004-0.00-10 airborne performed used calculated 0.037-0.158 0.021-0.030 0.004-0.0-10 used workplace range 0.037-0.158 0.0021-0.0300 workplace activities was calculated 0.037-0.158 0.0004-0.00-10 workplace TWA 0033 092 0.058 0.0004-0.00-10 PCME & 9.184 0.019 0.2964 00022 0.004 shake 0.0026 simulated and oposed Number events 266 wows wave simulated handling oposed Number 8 handling as handling handling spent handling min handling time clothes shake clothes clothes handling 15 15 15 measured clothes TEM measured clothes inactivity inactivity the to inactivty refers refers min compared handling min handling . 15 compared by Sha ke followed duration clothes shake clothes clothes Shake folowed followed shake handling conetraions laundry handling work laundry washed clothes load clothes per mm mm mm mm 666 handling concentrations clothes clothes loading handling loading underestimate done clothes active understimate done laundry laundry laundry eres min min clothes of underestimate ee} chrysotile min daily asuming during asuming airborne during as so 45 . asuming lower colected detects 30 presented detects PSO presented min presented study samples non calculation calculation 30 iinnitiiatliasamlples TEM calculation 15 calculation PSO conetraions our min and for min min min concentrations with 30 used min min concentrations from Samples 15 study concentrations Samples Loading PSO BYST Initial compared Calculated number Samples SO Initial Calculated out out chrysotile compared Calculated large out out also large shake shake study shake shake study post post results shake shake Initial out shake shake TWA The owing post during handling study shake and shake 8 conetraions handling | Bystander Loading Bystander conetraions initial Measured Current " During Post During Loading Bystander Measured initial Activity During During Bystander laundry initial home exposure potential from full shift exposures Sahmel et al control of airborne asbestos fibers 5 min length 0.25 min width and an aspect ratio of 3 settled out of the air fairly rapidly with fiber concentrations decreasing by 55 after 15 min and 85 after 30 min These data are useful for understanding and characterizing chrysotile exposure potential in a home environment with a typical air exchange rate 3.5 ACH after active fiber disturbance has ended This drop in airborne concentrations was more rapid than expected based on either gravitational settling calculations of asbestos exposure potential 43--46 or dilution ventilation models in the published literature The decline in fiber concentrations was more likely due to the effects of diffusion electrification impaction on other bodies centrifuga- tteixotnbootextkbosks.4.7-540 7a-g5g0 lomeration as described in particulate research and It was notable in this study that the workplace handling TWA air concentration ratios between the current study and the initial study remained consistent despite differences in certain study conditions and exposure factors The first of these for simulated exposures contamination different exposure factors was the use of a longer duration of time workplace with consistent of the clothing a over full work shift 6.5h in this study vs 30-45 min in previous study second the important difference : the betweenthe two stusdtudiesies was the ventilation rate in the chamber In the prior study an air exchange rate of 13-19 ACH was used during all study events whereas in current study air the room exchange rate of 3.5 ACH was used to more closely approximate the natural mechanical residential difference between in notable rate difference in ventilation rooms rates did a house This not appear to affect the personal sample results This consistency was not surprising because of the proximity of the clothes handler's breathing zone to the airborne fibers generated However the lower ventilation rate may have had some effect on BYST airborne concentrations the concentrations whwihcihch were 0.6 ofof the simulated workplace simulated concentrations concentrations weighted range 0.3-1.3 on an h time weighted basis in the current study vs 0.2 range 0.1-0.5 in the initial study potential A third exposure factor evaluated was the for chrysotile differences to occur in airborne concentrations during clothes handling owing to differences in work clothing fabric type Interestingly neither fabric type nor the age of the clothing appeared to have a significant effect on the overall airborne chrysotile result was csoonmceenwthraattiuonnesxpgeecnteerdataes d during it was handling clothes hypothesized that This new vs old fabrics or fabrics of different types could lead to differences electrical in fabrics charge or adherence properties of chrysotile fibers to Another notable finding of this study was that during both the active clotheshandling min of min of inactivity the mean and the subsequent 30 concentrations were approximately 10- 32 lower than the mean PCM concentrations and were statistically significantly different It appeared that a substantial number of clothing fibers in the counting range for the PCM analytical method were released from the work clothing during handling This result demonstrated that the use of PCM analysis alone to estimate handling exposures is likely to overestimate total asbestos exposure as clothing fibers can influence the results In the prior study which was conducted at lower chrysotile loading concentrations the relative PCME concentrations during clothes handling compared with PCM were even lower 55 85 lower than the mean PCM concentrations This suggests that it is important and in some cases critical to differentiate between asbestos and asbestos fibers when evaluating exposures associated with the handling of contaminated clothing There are very few other datasets against which the results of study compared early this can be The results of consistency studies conducted with findings inin the 1970s and 1980s suggest consistency with the findings of fi2015 Nature America Inc Journal of Exposure Science and Environmental Epidemiology 2015 1-15 10 Journal Table 2 Mean calculated 40 weighted average TWA PCME concentrations Assumptions used for 40 TWA calculation of Exposure Scien Activity . Samples used for calculation Sets of work Total time spent Loods of clothes washed Total duration of in room after Take of laundry done home per week per load of foundry clothes handling clothes handling Number shake min shake min of events . Mean calculated 40 TWA range cc Percent of loading 40 TWA range % . Current study _ Im Innooon and Loading Dunng shake During shake Post shake Loading 50 0-5 min SO 0-15 min PSO 15-20 min 1 Im Inoon 1 mm Innooon 1 mm In o on Post shake PSO 15-30 min 1 mm Inoon Envirometal Postshake PSO 30-45 min 1 mm In o on During and post shake SO 0-15 PSO 15-30 min 1 mm Innooon During and post shake SO 0-15 PSO 1 mm 15 15-30 PSO 30-45 min ~ N0 10 10 9.184 8.942-9.425 100 0550 N0 10 10 0.007 0.003-0.013 0.07 003-0.14 exposure 0550 N01010 0.018 0.007-0.032 0.20 0.08-0.34 0550 N0 10 10 0.004 0.001-0.008 0.04 0.01-0.08 0055550 N0 10 10 0.008 0.001-0014 0.001-0014 0.09 0.01-0.15 0055550 N0 10 10 0.003 0.001-0.005 0.03 0.01-0.06 0055550 30 N0 10 10 0027 0.009-0.045 N0 10 10 0.029 0.010-0 050 0.29 0.49 0.32 0 10-0.55 potenial Bystander during and post shake BYST 0-45 min 1 3 15 from During shake SO 0-15 min 2 3 500 During and post shake SO 0-15 PSO 15-30 min 2 3 30 30 6 0.012 0 006-0024 013 013 0.06-0.26 000 6 0037 0.015-0.063 040 0.16-0.69 30 6 0.053 0.017-0090 0.017-0 90 0.58 0 19-0.98 full Epidemolgy shift Initialstudy Loading , During shake Sahmel During and post shake 2015 Bystander during and post shake Initial study Initial study Initial study Initial study _ ~ 1555 1 6 1555 1 6 1555 1 6 1555 1055 4 0.2964 0.0976-0.549)1 . 100 1055 3 0.00052 0.043-0.061 0.00043-0.00061 0.25 0.10-0.44 1055 4 0.00045 0.00008-0.00081 0.17 0.03-0.27 1055 4 000009 0.00004-000015 0.00004-000015 0.04 0.01-0.10 0.01-0.10 et exposureal Measured 40 TWA airborne chrysotile concentrations are presented assuming weekly clothes handling and shake For comparison concentrations for both one and two loads of laundry per week were 1-15 calculated for a total of either three or six sets of work clothing The concentrations were then compared with the measured 40 simulated workplace airbome chrysotile TWA concentrations to determine the percent of the loading concentration The results are also compared with our initial study of lower airborne chrysotile loading concentrations Shake refers to handling and shake out activities performed to simulate laundry handling Initial study Calculated from min samples collected during 15 min of active handling followed by 15 min of inactivity TEM as opposed to PCME was used for the calculations in the initial study owing to the large number of PCM and TEM detects so as not to underestimate concentrations ' 2015 Nature America Inc. ' Table 3. home to occupational exposure concentration ratio values Ru for cumulative exposure calculations of clothes handling over time 2015 Average calculated home to Nature Activity Samples used for calculation Sets of work clothes washed per load of laundry Total duration of clothes handling shake Total time spent in room after clothes handling Average task concentration during simulated clothes handling C range h TWA for simulated workplace Coccan range occupational exposure concentration ratio RT range RT COCCB COCCB America Inc. Units Sample name Number of clothing sets handled min fice as task concentration min cc as task concentration cc as h TWA cc as -h TWA Current study During shake SO 0-5 min mmmm During shake SO 0-15 min mmmm Post shake PSO 15-20 min mmmm Post shake PSO 15-30 min mmmm Post shake PSO 30-45 min mmmm During and post shake SO 0-15 PSO 15-30 min mmmm During and post shake SO 0-15 PSO 3 15-30 PSO 30-45 min Bystander during and post BYST 0-45 min 3 shake 5 05 5 5 3.15 1.24-6 24 9.184 8.942-9.425 0.343 0.135-0,679 0555 15 2.94 1.17-5.05 9.184 8.942-9.425 0.321 0.127-0.550 0.127-0.550 myo oy 0555 1.87 0.53-3.64 9.184 8.942-9.425 0.203 0.058-0.396 0 15 1.31 021-2.17 021-2.17 9.184 8.942-9.425 0.143 0.023-0.237 0 15 0.45 0.15-0.83 9 184 8.942-9.425 0.049 0.016 0.090 myoooyy 055555 2.13 0.69-3.61 9.184 8.942-9.425 0.232 0.075-0.393 15 30 1.57 0.51-2.68 9.184 8.942-9.425 0.171 0.055-0.292 15 30 0.62 0.31-127 0.31-127 9.184 8.942-9.425 0.068 0.034-0.138 initial study During shake Initial study Post shake Initial study During and post shake Initial study Bystander during and post _ Initial study shake 1000 youn 0 0.083 0.068-0.097 0.311 0.098-0.549 0.397 0.155-0.697 youn 1000 15 0.011 0.009-0.014 0.09-0.014 0.311 0.098 0,549 0.054 0.020-0,092 1000 youn 15 0.035 0.006-0.063 0.296 0.098-0.549 0.132 0.024-0.215 1000 15 15 0.007 0.003-0.011 ) 0.296 0.098-0.549 0.034 0.012-0.082 from home activities can be estimatedestimated using the RTH values in this table and the following equation Coccs XRTH EX EXEXC EXEXC EXEXC EXEXC where CE is the cumulative The cumulative exposure potential is the concentration for the worker in cc as an h TWA RTH is the home to accupational concentration ratio for the Take lifetime exposure from handling contaminated clothing in years Coccs exposure clotheshandling exposure time in hours per week E is the handling exposure frequency specific handling scenario of interest units of cc as a task concentration as an h TWA Er is the Journal 2000hours The Sahmel in and CF is the conversion factor for a cumulative occupational or cumulative environmental year in OT yent 8760hours RT value used in home of itnhiws ecealkcsulyateioan srhoiulsd btehesedluercatteidonbaosfecd lonoktnhowensihnanfdliongremaxtpioosnuraeboutyetahersclotheshandling scenario of interest For example a different RH value would be selected if clothing is handled for 5 min 0.08 h or 15 min et and whether not the household household individual remains in the room following clothes handling Cooch can be measured or estimated for various tasks or job titles from the al 0.25 h perlihteraatnurde lThiisnstgudeyvaenndt the prior studyorinvolved simulatedsimulated occupational exposures within a range of 0.1 to 9f as an h TWA thus the results presented here are best suited to address home and shake activities performed to simulate laundry handling On published Exposure cumulative exposures for workers who were exposed to airborneairborne concentrations between these values Shake refers to handling exposure of the values from each of the six clothes handling and shake events in our study TEM as opposed to PCMEPCME was used for the calculations in the initial study owing to the large number of PCM 28 study the basis average and TEM detects so as not to underestimate concentration On the basis of the average values from three handling and shake events in our initial On the basis of average values from four handling and shake events in our initial study Calculated from 30 min samples collected during 15 min of active handling followed by 15 min of inactivity Calculated by averaging the appropriate Saciennd potenial 15 min measured values from Envirometal full shift Epidemolgy exposure 2015 2015 1-15 11 12 Journal Table 4. Example cumulative exposure estimates based on the mean home to occupational exposure concentration ratio RI Low occupational loading Moderate occupational loading of Core 01f cc as h TWA Cour 1f as h TWAJ High occupational loading Coce 9f as h TWA home cumulative Exposure exposure home cumulative exposure home cumulative exposure Saciennd home Scenario concentration Mean hame . * home tosk . to occupational Total home task exposure exposure exposure occup env home task exposure concentration exposure occup env concentration occup env year year cc conrcateinotrRataion wenmee k coCnracsekntcraction cc year year Clask f cc Cast c year year pexoptoesnurieal 0.0051 0.046 Currentstudy 0.034 0.0018 0.00041 034 0.0041 During shake SO 0 5 min 0.0050 0.050 900 Dunng shake SO 0 min 0.00024 0.0024 Post shake PSO 15 min 0.0022 400 Post shake PSO 15 30 min Envirometal 0049 0.00077 000017 0.0077 0.0017 140 Post shake PSO 30-45 min from 00073 0.0017 0.23 1300 During and post shake 0.343 0.321 0.203 0.143 0.232 5 5 50 GGGE88 555550 0032 GGGE88 00011 0.32 0.20 190 5550 0.020 GGGE88 00011 555550 0.014 GGGE88 0.14 0.00051 0.049 0.44 555550 GGGE88 0.0049 555550 0.023 GGGE88 STANOW 0.018 3.1 STANOW 0.011 2.9 STANOW 0.011 1.8 STANOW 0.022 1.3 STANOW STANOW 0.073 0.017 2.1 320 016 0.45 0037 010 0.10 0.022 0.20 0.069 0.016 0.65 0.15 SO 0-15 PSO 15-30 min During and post shake 0171 45 0017 36 0.0080 0.0018 0.17 160 0.080 0.018 15 1400 0.72 16 full SO 0-15 PSO 15-30 min 30-45 min Epidemolgy shift Bystanderduring and post 0068 45 0.0068 6.4 00032 0.00072 0068 . 0.032 0.0073 0.61 570 029 0.065 shake IBYST 0-45 min 2015 Initial study During shake 1-15 shake During and post shake Bystander during and post shake Sahmel 0.397 15 0.040 12 00062 0.0011 40 120 0.062 0014 3.6 1100 0.56 0.13 150 0.017 et exposure 0.054 15 0.0054 1.7 000084 0.00019 0.05 0.0084 17 0.0019 0.5 1.2 0.076 740 0.37 0.085 al 0.132 30 0.01.3 8.2 0.0041 0.00094 0.13 83 0.041 0.0094 0.10 0.022 0.034 30 0.0034 2.1 0.0011 0.00024 0.034 21 0.011 0.0024 0.31 190 concentrations of year assuming weekly handling and laundry room activities lasting 5-45 min per week An exposure frequency 25 years was selected based on the estimated upper bound Cumulative exposure presented that worker will remain in a single job Event exposure times were set equal to the sampling times A standard occupational exposure frequency of 50 weeks was assumed The for the amount of time a Shake refers to simulated handling and shake activities performed prior to laundering Cask R results are compared with our initial study of lower airbome chrysotile CE = 20020000 year year.env = CEfice 8760 The samples included in the current study " ^ 1 ^ x 25 hour TH Case CEffcc hour Crask ^ min 60 min50 year year / occup CEffcc = scenarios are indicated in parentheses Initial study.28 @ 2015 Nature America Inc measured the handling of clothing worn during the removal of containing building materials The author presented airborne concentrations collected at a distance of 1.5 meters from contaminated clothes handling and reported that the concentrations ranged from ND to 0.4f over variable time durations using PCM The PCM concentrations measured during clothing SO in this study were consistent with the PCM concentrations reported by Sawyer Additionally in 1982 Mangold27 compared the mean airborne fiber concentrations for individuals wearing light medium or heavily contaminated clothing and found a correlation between the airborne fiber concentrations and the different levels of clothing contamination The current study resuits are consistent with the reported findings by Mangold in that airborne fiber concentrations were correlated with the magnitude of clothing contamination However as previously mentioned neither Sawyer nor Mangold measured the asbestos proportion of measured airborne fibers by TEM and thus additional direct comparisons with these studies are not possible On the basis of the statistically significant a = 0.05 lower PCME concentrations as compared with the PCM concentrations observed in both this study and the prior study it appears likely that an appreciable fraction of measured fibers was due to the clothing particularly with decreasing asbestos workplace concentrations More recent simulation studies 2008-2009 evaluating the handling of clothing worn during work activities with asbestoscontaining friction products have generally shown that airborne asbestos exposures from simulated laundering activities of contaminated work clothing were undetectable or were a fraction of the exposures experienced in the simulated occupational environment A study evaluating exposures during the unpacking and repacking of clutch parts reported mean worker exposures ranging from 0.002 to 0.231 cc PCME over a min time period and a corresponding mean chrysotile concentration during the handling of clothing worn during these activities of 0.003 cc range 0-0.005 cc by PCME In a similar study involving unpacking and repacking of automobile brake pads and shoes mean worker exposures ranging from 0.004 to 0.541 cc PCME min resulted in corresponding clothes- cc handling exposures of 0.011 cc range 0.007-0.015 by PCME for detectable samples In a simulation study to characterize exposures during the removal of containing heavy equipment brakes mechanics were exposed to mean airborne chrysotile concentrations ranging from 0.003 to 0.044f cc by PCME with subsequent mean handling exposures of 0.036 cc by PCME for the samples in which asbestos was detected A fourth study evaluated airborne concentrations associated with clothes handling in a small chamber of 1501 0.15 min volume making the results difficult to compare with concentrations measured in larger study chambers or rooms such as this study Additionally for all four of these studies the exposure conditions were different from the current study in that the impact of work with specific products was evaluated rather than the effect of a specific target occupational concentration on handling exposures As with any study despite the careful design and data collec- tion process there are several factors that should be considered when evaluating the results presented here The use of stationary mannequins as a surrogate for active workers to load the work clothing with chrysotile may have affected the potential for fibers to deposit and remain adhered to the clothing It is plausible that movement by workers could lessen although perhaps to a negligible extent the concentration of fibers deposited on or adhered to the clothing at the end of the work day Additionally this study did not consider the effects of commuting or blowing brushing off of work clothing before entering the home It is likely that these activities if they occurred would have removed some of the fibers adhered to work clothing before they could be home exposure potential from full shift exposures Sahmel et al 13 brought into the home environment In contrast this study was designed to maximize the number of fibers that remained adhered to the clothing between the workplace loading and handling events This study did not specifically assess the home fiber resuspension exposure potential from other surfaces or materials other than resuspension from active clothes handling However based on previously published data on fiber adherence and reentrainment from other surfaces it appears unlikely that substantial airborne asbestos concentrations could be generated simply by moving around in rooms where asbestos fibers have settled out of the air or where contaminated clothing has pre- viously been shaken out and handled.4 Esmen performed experimental measurements which supported the conclusion that fibers which are adhered to a surface will require air speeds of at least 10 m to become resuspended into the air This air speed is much higher than would be encountered in an indoor environment without mechanical disturbance and therefore normal air currents in an indoor space would likely be insufficient to resuspend settled asbestos fibers Similarly in a U.S. EPA report on the resuspension of fibers from indoor surfaces due to human activity the authors remarked that no measureable dusts were observed from particulate deposits on bare flooring It could be conjectured that resuspending dust from bare floors requires substantial turbulence from either stomping or very fast walking to provide the energy to both release particles from the surface and elevate them into the air sufficiently to add to the air concentration Low pile outdoor carpeting also provided essentially immeasurable air concentration levels Testing data using asbestos surrogate Wollastonite fibers in medium pile carpets showed some fiber release under certain conditions but the results were difficult to interpret because airborne fiber concentration measurements were not reported using relevant dimension criteria such as PCM If household cleaning or laundering activities involving mechanical disturbance did yield the resuspension of fibers brought into the home on workers clothing it is likely that fibers in the PCME size range would settle out of the air at a similar rate as was observed following clothes handling in this study As seen in Figure 6 both PCM and PCME fiber concentrations decreased significantly within approximately 30 min after clothes handling ended It should also be noted that this study evaluated clothes- handling activities between 5 and 15 min in duration which is likely to be at the upper end of plausible clothes handling duration prior to laundering In this study min and min handling airborne concentrations were not statistically significantly different but the weekly TWA concentrations for 5min clothes handling were approximately one third of the TWAS for min clothes handling 0.003-0.013 cc as a 40 TWA for 5min clothes handling vs 0.007-0.032 as a 40 TWA for min clothes handling This finding suggested that exposure duration is an important factor for evaluating the exposure potential associated with handling activities . And finally this study focused on chrysotile asbestos Physical differences have been noted between the amphibole and chrysotile minerals that could affect home exposure potential including surface electrical charge differences in fiber shape and possible differences in affinity for surfaces and agglomeration However it is possible these physical differences may have little effect on the surface adherence and release behavior of the different asbestos fiber types CONCLUSIONS The results of the current study indicated that for loading over a full work shift at h TWA airborne concentrations of approximately 9f the household concentrations related to the handling of contaminated work clothing were consistently a small '2015 Nature America Inc Journal of Exposure Science and Environmental Epidemiology 2015 - 15 home exposure potential from full shift exposures Sahmel et al 14 proportion of the simulated workplace airborne exposures When the results of this study were considered together with the prior study a clear trend was seen of increasing TWA airborne concentrations of asbestos during clothes handling with increas- ing TWA workplace concentrations in ratios of approximately % or less for clothes handling to workplace concentrations These ratios remained consistent even with the use of a substantially lower ventilation rate of 3.5 ACH in the current study compared with 13-19 ACH in the initial study.The results confirm that dilution ventilation rates did not have a significant impact on personal exposures resulting from airborne fiber concentrations generated in an individual's breathing zone this was not altogether surprising as dilution ventilation has little impact on personal breathing zone airborne concentrations for the primary worker On the basis of measurements collected for passive exposure potential over 30 min following active clothes handling the data indicated that the rate of settling of PCME fibers is faster than has been previously suggested by either ventilation models or gravitational settling calculations The results also demonstrated that the use of the PCM vs PCME analytical method overestimated chrysotile exposure potential by 11-47 in the current study and 2 to fold in the initial study owing to the presence of clothing fibers Despite differences in simulated workplace airborne concentrations of more than an order of magnitude between the two studies the corresponding estimated weekly household handling TWA concentrations remained at approximately 0.25 of the workplace concentrations on a weighted basis home cumulative exposure estimates based on a greater than year period of weekly laundry activities by a single household contact were below 1 year for handling contaminated work clothes worn in an occupational environment with an airborne chrysotile concentration of up to 9 cc 8 TWA 6 Gibbs AR Jones JS Pooley FD Griffiths DM Wagner JC occupational malignant mesotheliomas IARC Sci Publ 1989 219-228 219-228 7 NIOSH Report to Congress on Workers Home Contamination Study Conducted Under the Worker's Family Protection Act 29 U.S.C. 671a NIOSH Pub No. 95 123 September 1995in National Institute for Occupational Safety and Health Cincinnati OH 1995 8 Donovan EP Donovan BL McKinley MA Cowan DM Paustenbach DJ Evaluation of take home para occupational exposure to asbestos and disease a review of the literature Crit Rev Toxicol 2012 42 703-731 9 Goswami E Craven V Dahlstrom DL Alexander D Mowat F Domestic asbestos exposure a review of epidemiologic and exposure data Int J Environ Res Public Health 2013 10 5629-5670 10 Vianna NJ Polan AK Non occupational exposure to asbestos and malignant mesothelioma in females Lancet 1978 1. 1061-1063 . 11 Magnani C Terrac~-n~B- Ivaldi C Botta M Budel P Mancini A et al A cohort study on mortality among wives of workers in the asbestos cement industry in Casale Monferrato Italy Br J Ind Med 1993 50 779-784 12 Camus M Siemiatycki J Meek B Nonoccupational exposure to chrysotile asbestos and the risk of lung cancer N Engl J Med 1998 338 1565-157 13 Bourdes V. Boffetta P Pisani P. Environmental exposure to asbestos and risk of pleural mesothelioma review and meta analysis Eur J Epidemiol 2000 16 411-417 14 Enterline PE Henderson V. Type of asbestos and respiratory cancer in the asbestos industry Arch Environ Health 1973 27 312-317 15 Hodgson JT Darnton A. The quantitative risks of mesothelioma and lung cancer In relation to asbestos exposure Ann Occup Hyg 2000 44 565-601 16 16 Berman DW Crump KS Final Draft Technical Support Document for a Protocol to Assess Asbestos Risk October 2003 EPA 9345.4-06 Environmental Pro tection Agency EPA Office of Solid Waste and Emergency Response Washing- ton DC US 2003 Report no EPA 9345. 4-06 17 ERG Eastern Research Group Report on the Peer Consultation Workshop to Discuss a Proposed Protocol to Assess Asbestos Risk Prepared for the US Environmental Protection Agency USEPA Office of Solid Waste and Emergency Response Washington DC EPA Contract No. 68 C 98 148 Work Assignment 2003-05 30 May 2003. Lexington MA Eastern Research Group 18 Berman DW Apples to apples the ongin and magnitude of differences in asbestos cancer risk estimates derived using varying protocols Risk Anal 2011 31- CONFLICT OF INTEREST At the ume of the study 8 of the 13 authors were employed by Cardno ChemRisk a consulting firm that performs scientific research and support for the government corporations law firms and various professional organizations The other five authors were employed by RJ Lee Group an analytical laboratory and consulting firm A portion of the funding for the preparation of this article and the underlying research was provided by John Crane Inc. a manufacturer of sealing devices that historically manufactured or supplied asbestos containing gaskets and packing Funding was also provided by Cardno Chem" isaknd the RJ Lee Group Cardno ChemRisk has been engaged by John Crane Inc to provide general consulting expert advice and litigation support on scientific matters involving asbestos This paper was prepared and written exclusively by the authors without any review or input by John Crane Inc employees or legal counsel Seven of the authors DJP JLH DG JS AKM PUL and DVO have served as expert witnesses regarding historical exposures of various tradesmen to asbestos AKM JLH and DG have testified on matters related to the historical use of containing gasket and packing materials on behalf of John Crane Inc. 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