Document 4JdREVjpvLDwbKmkdoBbpK3oV

FILE NAME: Union Carbide (UC) DATE: 2008 May DOC#: UC382 DOCUMENT DESCRIPTION: EPA Report - Atlas Asbestos Mine Superfund Site Atlas Asbestos Mine U . S , C u m . o. ' ,' P( i t , 'ift Av i n * * H ' 0 * 5 h', * A * Me < 2 0 0 8 U.S. EPA R eleases E xposure a n d Risk A ssessm ent tor C le a r C re e k M a n a g e m e n t A re a B ackg ro u n d In 1991, U.S. EPA signed the Record of Decision (ROD) selecting the cleanup remedy for the Atlas Asbestos Mine Su perfund site in San Benito and Fresno counties, California. In the ROD, EPA noted that it was not proposing any action for the Clear Creek Management Area (CCMA), one of the Atlas site's four geographic areas. Instead, EPA stated that it would evaluate whether the United States Department of In terior Bureau of Land Management's (BLM) plans for man agement of CCMA were adequate to procect public health from exposure to asbestos found in the Areas soil and air. The BLM is the agency' responsible for administering the public lands of CCMA. In 2004, as part of the process of evaluating the completeness of the Adas Mine cleanup for possible delisting from the fed eral Superfund list, EPA Region 9 initiated an asbestos expo sure and human health risk assessment for the CCMA. The goal of the assessment was to use current asbestos sampling and analytical techniques to update a 1992 BLM Human Health Risk Assessment and provide more robust informa tion to BLM on the asbestos exposures from typical CCMA recreational activities and the excess lifetime cancer risks asso ciated with those exposures. BLM will use the information to evaluate management and use alternatives in an upcoming environmental impact statement for managing the CCMA. The assessment was conducted consistent with U.S. EPA policy and guidance, including the Risk Assessment Guid ance for Superfund (RAGS) (EPA/540/1-89/002). and with the encouragement of the California Air Resources Board (CARB) and the California Department o f Toxic Substances Control (DTSC). Photo 1 The. CCMA contains the largest natural deposit of asbestos in the United States. Commercial asbestos mines operated in the deposit, including the Atlas Mine and the Coalinga Mine, which were addressed by the federal Superfund pro gram. Dust-generating activities, like riding motorcycles on the roads and trails of the CCMA, can release asbestos into the air where it can be breathed into the lungs. Asbestos is a known human carcinogen, causing lung cancer and mesothelioniJ*. as well as chronic and debilitating non-cancer respira tory disease. Exposure Assessment Asbestos Air Sampling fn 2004 and 2005, Region 9 collected air samples while EPA employees and contractors participated in typical recreational activities at the Clear Creek Management Area. The samples were collected from the breathing zone of individuals riding motorcycles and all-terrain vehicles (ATV), driving and riding in sports utility vehicles (SUV), hiking, camping, sleeping in a tent, fence-building, and washing and vacuum ing vehicles after use at CCMA. Sample cassettes were placed to collect air samples representing the breathing zone heights of both adults and children (Photo 1), and samples were collected for both lead riders and those trailing be hind them (Photo 2). These activity- based air samples were then analyzed for asbestos. Photo 2 `Words in italic are defined in the Glossary on page 9. Results it is important to note that the asbestos concentrations used by EPA in the exposure and risk as sessment and discussed in this fact sheet are for longer fibers known as phase contrast micros copy equivalent, or PCME, fibers. PCME fibers are those fibers whose shape and size have been most closely linked to asbestos disease. The Activity Drives the Expo sure - Figure 1 shows the indi vidual sample results for each ac tivity and for measurements of CCMA ambient air. The data shows that the activities which typically create the mosr soil dis turbance and dust, motorcycling, ATV driving/riding, and SUV' driving/riding, also release the most asbestos into the breathing zone. In some instances, the con centration of asbestos measured in the EPA samples even exceeded what the U.S. Occupational Safety and Health Administration (OSHA) sets for workers as a 30minute limit for asbestos. Position Is Im portant - Figure 2 shows the results for motorcycle riders in the lead and trailing be hind and for ATV and SUV drivers/riders. First trailing drivers/ riders encountered higher asbes tos air'concentrations than lead drivers/riders and second trailing drivers/riders typically encoun tered higher levels than first trail ing. This means that the asbestos levels in the air increased with rhe larger dust clouds encountered by those riders following one or more riders ahead of them. Figure 1: Com parison of Am bient Concentration and Activities z Ambient -> Motorcyclist ATV Driver/Rider SUV Driver/Rider v Hiker > Camper Powerspray Wash Hose Wash HEPA Vacuum Regular Vacuum * Fence Builder Figure 2: Comparison of Different Riding Positions for Adults a u=3 So CL 0.5 x$ Ambient Lead x First Trailing * Second Trailing Ambient Motorcyclist ATV Driver/ SUV Driver/ Rider Rider Hiker Page 2 A tlas A sb e sto s M ine Su p e rfu n d Site w^AAAAA<M W > w > w w ^ f t W>w><><><yvwv^wvwvtfVMvywv^^ Figure 3: Comparison of Different W eather Conditions for Adult Receptors 25-t > Dry (2004Sep) Lead i- 2- C o <5- n 3 <a5 SC at S o a 0.5- 0 > A 0 A A g Ot a * Motorcyclist -> Dry (2004Sep) Trailing Dry (2005Sep) Lead o Dry (2005Sep) Trailing * Moist (20Q4Nov) Lead = Moist (2004Nov) Trailing Wet (2005Feb) Lead $ I 1 * ' 8 s n Wet (2005Feb) Trailing _____________ L j_____________ J_6_c_____ ATV Driver/ Rider SUV Driver/ Rider Hiker Figure 4: Windows O pen vs. Windows Closed Scenarios (Septem ber 2005 - Ail Positions) 1 2 -, 08 & o Si V A x SS a Open Closed Wet Weather Reduces But Does Not Eliminate Exposure - Figure 3 shows the effect of sampling event weather conditions on as bestos air concentrations. Using rainfall patterns and on-site ob servations, the September 2004 and 2005 events were determined to be conducted under "dry" con ditions, with little or no precipi tation in the month prior to the event. The November 2004 event was designated as occurring under "moist" conditions, with two to three inches of rain in the two weeks before the event. The February 2005 events were con ducted under "wet" conditions, with rain immediately before and during the events. Based on the sampling results, it appears that only active rainfall reduces asbes tos air concentrations, although further study would be needed to define the exaci conditions neces sary to reduce dust generation and asbestos exposure. SUV Exposures Were Significant - As shown in Figure 4, driving on the unpaved CCMA access roads resulted in significant mea sured asbestos air concentrations inside the vehicles, even with the windows closed and the air sys tem set to "recirculate". O AA Q. A SUV Driver/Rider M ay 2008 Page 3 Child Exposures Tend to Be Higher - Figure 5 shows the ratio between the child and adult Figure 5: Ratio of Child to Adult Exposure Levels for Each Activity for Each Sampling Date samples collected at the same time on the same sampler i.e. the ratio between the child and adult sample cassettes shown in Photo 1. With the exception of the lit S camping activity, the majority' of O a. child exposures exceeded the ex t 3 posure recorded for the paired n< adult sample. In total, the asbes <3 tos concentration in the child isll sample exceeded the concentra 0. tion in the adult sample 64% of 2 2 the time. o .2 Amphibole Asbestos was De X Motorcyclist ATV Driver/Rider ' SUV Driver/Rider Hiker x Camper - - ' Ratio t tected in the Air Samples -- While chrysotile asbestos was the predominant asbestos mineral Nov 2004 Feb 2005 Sep 2005 type found in the EPA air samples, almost 8% of the PCME fibers were identified as tremolite, actinolite, or an other amphibole asbestos mineral. There is an emerging con sensus in the scientific community that amphibole asbestos Scenario 5 Combined Rider/Workday: Drive in. stage, ATV or motorcycle riding, fence building/re pair, stage, drive out, vehicle wash, vehicle vacuum. may present an even greater health risk. The typical worker scenarios are: Risk Assessment Scenarios Seven typical CCMA use scenarios- were created from the in dividual activities for which EPA collected air samples. Risk estimate calculations were then conducted for the scenarios. The scenarios were designed to make the risk estimations bet ter reflect typical CCMA use patterns and provide more Scenario 6 Patrol: Stage at Section 8 outside of CCMA, drive in and stage ar CCMA (lead driver/ rider SUV, ATV or motorcycle pan oiling), stage and drive our, vehicle wash, vehicle vacuum, unpacking at Section 8. Scenario 7 SUV/Truck Patrol: SUV/truck patrol (lead SUV only), vehicle wash, vehicle vacuum. useable information to BLM and the public. The scenarios were developed with input from BLM and D'l SC. Five of the seven scenarios represent recreationai/volunteer use of CCMA, and two represent typical worker use. The five rec reational scenarios are: Scenario 1 Weekend Rider: Drive in, motorcycle on Saturday, camp on Saturday, sleep in tent, camp on Sunday, motorcycle on Sunday, drive out, vehicle wash, vehicle vacuum. Scenario 2 Day Use Rider: Drive in, stage (prepare for riding), ATV or motorcycle riding, stage, drive out, vehicle wash, vehicle vacuum. Scenario 3 Day Use Hiker: Drive in, stage, hike, stag e , drive o u t. Scenario 4 Weekend Hunter: Drive in, hike/hunt on Saturday, camp on Saturday, sleep in tent, camp on Sunday, hike/hunt on Sunday, drive out, vehicle, wash, vehicle vacuum. Risk Assessment Methods - Excess Lifetime Cancer Risk es timates were calculated for the scenarios using both the U.S. EPA Integrated Risk Information System (IRIS) and the California EPA Office of Environmental Health Hazard As sessment (OEHHA) toxicity values for asbestos. These are standard methods for estimating risk. Adult, Child, and Child/Adult Risk Estimates - Consistent with the EPA Risk Assessment Guidance for Superfrmd (RAGS), a 30-year exposure duration was used for estimating excess cancer risks from the CCMA adult recreational and worker exposures. The risk assessment estimates risks for an adult who visits CCMA for 30 years, a child who visits for 12 years (ages 6 to 18) with his/her parents and then contin ues to visit for ari additional 18 years as an adult (30 years total exposure), and a child who visits for 12 years from ages 6 to 18. Page 4 A tlas A sb e sto s M ine Su p erfu n d Site CCMA Use Frequency - The EPA M G S guidance requires that risks be estimated for the reasonable maximum exposure (RME) that is expected to occur at a site under both current and future land-use conditions. Based on surveys and inter views, an earlier risk assessment conducted by BLM esti mated a CCMA recreational RME of five off-road vehicle rides a year. Because some users indicated that they rode more frequently, the BLM assessment also used a "high" esti mate of 12 days per year. Risks were also calculated for one day per year to provide a range of estimates and exposures. The EPA risk assessment incorporates the 1, 5, and 12 visitper-year frequency of the earlier BLM assessment for Sce narios 1 through 5 and, at BLM's request, uses a 1, 60, and 120 day-per-year frequency for the worker Scenarios 6 and 7. Risk Assessment Results - Excess Lifetime Cancer Risk esti mates for Adult, Adult/Child, and Child exposures using the U.S. EPA IRIS risk model are shown in Figures 6, 8, and 10. The Excess Lifetime Cancer Risk estimates using the Cal/ EPA OEHHA model are shown in Figures 7, 9, and 11. For reasons thar are explained in more detail in the risk assess- mem report,.the OEHHA toxicity value for asbestos is eight times higher than the IRIS value, and the OEHHA risk esti mations are therefore eight times higher. The IRIS and OEHHA risk estimates can be thought of as bracketing the range o f possible risks from CCMA asbestos exposure. The EPA Superfund program defines the acceptable risk range for exposure to a carcinogen, like asbestos, as 10'4 (1 in 10,000) to 10'6 (1 in 1,000.000) excess lifetime cancer risk. Exposures which are calculated to cause mote than 1 in 10,000 excess cancers are considered to be of concern and may require action to reduce die exposure and resulting risk. It is important to note that the risk assessment present quan titative estimates of excess cancer risk over a lifetime in a population based on the defined exposure scenarios. The scenarios have been designed to represent current and future exposures for recreational and working users of CCMA. The numbers do not predict individual exposures or individual health outcomes. W hat Do The Results M ean? There was no combination of scenario, toxicity value, or vis its per year that was below the risk of 1 in 1,000,000. Using the IRIS model, as shown in Figure 6, EPAs risk estimations found that, with the exception of Scenario 3 Day Use Hiker, making five or more visits to CCMA per year ovet a 30-year period would put recreational users above the 10'4risk range (1 in 10,000). Only Scenario 3 (Day Use Ffiking) had risk calculations within the acceptable range. The highest IRIS risk estimations, 2 x 10'5(2 in 1,000), were calculated using the 95% UCL exposure concentration for 12 visits per year for recreational Scenario 1 and 120 visits per year for worker Scenario 7 (SUV' Patrol). Figure 6: Adult C ancer Risk, Scenarios 1 - 7: M ean and 95% Upper Concentration Limit (UCL) Exposures Using IRIS Unit Risk *istwum waft*!* O*cS*it>fsc>e!Kn2 tSeyewltett*fe tfcs* ftd Kkl- Wcfc StoMxtffttSfXxsA SCK*<S>5 xiseri SAfet.Weok y<;Mt<VkJ<U>v 4:<y ttowcyfc stjvftcwf't ?<*! M ay 2008 Page 5 Using the OEHHA model, even one visit per year for recreational Scenarios 1, 2, 4, and 5, creates a risk that exceeds EPAs acceptable range (Figure 7). The higher risks reflect the fact that the OEHHA asbestos toxicity value is eight times higher than the value in IRIS. At the high end of the risk range, excess lifetime can cer risk estimations using the OEHHA model and the 95% UCL concentration level indicate that recreational users riding mo torcycles 12 weekends per year (Scenario 1), and workers per forming SUV patrol duties at CCMA (Scenario 7) for 120 days per year during a 30-year career, could have as much as a 1 in 100 (1 x 10'-) chance o f developing asbestos-related cancer. It should be noted that neither the IRIS nor OEHHA models are de signed for very high exposure lev els, so the absolute number calcu lated for the high-end risk has a higher degree of uncertainty than the numbers calculated for the lower exposure scenarios. How ever, the risks are still extremely high. The Child/Adult estimations us ing the IRIS model found that five or more visits per year for Scenarios 1 through 4 was above the 10 "4risk range (Figure 8) and all visits were above the accept able range using the OEHHA model (Figure 9). Figure 7: Adult C ancer Risk, Scenarios 1 - 7 : M ean and 95% UCL Exposures Using OEHHA Unit Risk ito id ito't : Vo;* 4vA&y*-'*.' s Sr V ,. ; 'Cvfeys.V?' cfifccAi : ^Avy.<#!>m.' }*&. I i m un \ >HVf,< ; >'.1946 w KstaricH accorto3 y/to& oxl O xy Uso to y to x (ATv) wc# tonfcoxot 6<xW:<otf SActoVWPxrttooA Wotaftiytfe toSfictotoTtoot?dc (AYv) $R&yto&-yoto> Figure 8: C hild/A dult C dncer Risk, Scenarios 1 - 4: M ean and 95% UCL Exposures Using IRIS Unit Risk fW'-Ji I i `/''OOJ Iy 16 m Page 1 i S0xc>w>iUtxt*oR2aba 2>UyOvKyRii<o.<Wtfio: >oyUs<*Hito* 54 Afeofeot* tPtwi A tlas A sb e sto s M ine Su p erfu n d Site Figure 9: C hiid/A duit C ancer Risk, Scenarios 1 - 4: M ean and 95% UCL Exposures Using OEHHA Unit Risk For the Child risks, which were calculated lor a 12-year exposure from ages 6 to 18, less than five visits per year for Scenarios 1 and 2; one, five, and twelve visits for Scenario 3; and one and five visits per year for Scenario 4 were within the acceptable risk range using IRIS (Figure 10). Using the OEHHA model, only less than five visits per year for Sce nario 3 Day Use Hiker was within the acceptable range (Fig ure 11). iW f 5K4?fWb>1 Zcfrn OayifcsHKw W6tsftKdrtiw <ATV) Figure 10: Child C ancer Risk, Scenarios 1 ~ 4: M ean and 95% UCL Exposures Using IRIS Unit Risk 1 in W- i f.wa{<j>x>a<>............................................. Wesfowai Rider Oa U$ <A7y> S>:wk2 DayUseRidir ?.www&>3 Scw>^ tte *f i Ws eke Wfri*r UWWWWWWa*MMMWSIUtBWWMWWWWUWWlMMMflWWWW'ftfl6 a a M ay 2008 Page 7 Limitations of the Assessment With any assessment of risk, there are assumptions and variables that can cause the calculations to either overestimate or underesti mate the actual risk. The CCMA risk assessment report contains a more detailed discussion of the exposure and toxicity parameters which affect the calculations of estimated risk. Figure 1 : Child C an cer Risk, Scenarios 1 - 4: M ean and 95% UCL Exposures Using OEHHA Unit Risk :x '$% .v/Mw Svfr > H| :v'V.w ** 1 f\t1.#*i The CCMA assessment may overestimate or underestimate risk if EPAs measurements of ex posure and the assumptions of exposure frequency' are either greater or less than actual condi tions. Additional uncertainty is w Stvesissit! i introduced because both the IRIS and the OEHHA toxicity values for asbestos are based on epide miological studies of work place exposures to intermittent high asbestos concentrations over extended periods. While the concentrations measured for activities at CCMA are sig nificantly elevated, the exposure is infrequent and episodic. Because there is no clear mode of action for asbestos-induced disease and no threshold for cancer health effects, using a di rect time-weighted extrapolation from the longer, chronic occupational exposures to shorter-term, episodic exposures , may underestimate or overestimate the risk. The risks could be much lower because the exposures may be too infrequent or the total retained fiber burden too few to initiate the as bestos disease process. O n the ocher hand, the EPA risk calculations may underesti mate the risk because take-home exposures and non-cancer health effects were not considered. Asbestos can adhere to equipment, clothes, and the interior and exterior of vehicles, and can be tracked out of CCMA resulting in future expo sures to CCMA users, families, and communities. The off site exposure could increase the risk, proportional to the time of exposure and the concentration of asbestos tracked off site. Perhaps most important, there is currently no reference value for calculating non-cancer risks from asbestos exposures and non-cancer risks were therefore not addressed in the EPA assessment. However, epidemiological studies indicate that non-cancer respiratory health effects from exposure to asbes tos can be significant and in some studies exceed the cancer cases. Therefore, the general probability of developing dis ease from exposure related to activities at Clear Creek may be significantly underestimated in the EPA risk estimations. , t&asiai (ATv'l Sfoir.atXi 2 tfe UAttfttfci Sissric.3 Cay s Hike- Scenrio i Watto&yHw>4p Conclusions Asbestos is a known human carcinogen. Despite the uncer tainties inherent in risk assessment, the EPA evaluation of asbestos exposures and risks at the Clear Creek Management Area has led to some important conclusions' The Activity Causes the Exposure - The concentra tion of asbestos in the breathing zone is directly re lated to the degree that an activity disturbs the soil and creates dust. Children Are of Special Concern - In a majority of the samples, the concentration of asbestos measured in the child's breathing zone exceeded the asbestos concentration in the companion adult sample. Fur ther, a child's life expectancy exceeds the latency pe riod for asbestos-related disease. The Higher the Exposure, the Higher the Risk - The activities with the highest exposure - motorcycling, ATV riding, and SUV driving/riding - had the high est corresponding excess lifetime cancer risk. Reducing the Exposure Will Reduce the Risk - The risk of developing asbestos-related disease is depen dent on the level of exposure, the duration of expo sure, and the time since first exposure. Reducing exposure will reduce the risk of developing asbestosrelated cancers and debilitating and potentially fatal non-cancer disease. In summary, the asbestos exposures that EPA measured at CCMA are high and the resulting health risks are of concern. Page 8 A tias A sb e sto s M ine Su p erfu n d Site G lo s s ary Actimty-bmedsampling~ Activity-based sampling of the air in the breathing'one of an indivtduaiwhile that in dividual pattieipates in typical work Of recreational ac tivities. It has been used for decades by industrial hy- gtenists to measure personal exposures in workplace environments, it is mote representative of actual indt-: viduai exposures than fixed, searionaty monitors and soil samplhsg,and isbying used by EPA to sample exposures " :'-ata^esros;sti^ ;aimisxt^'bptanrtjs^y'"''' ...:h;suftduhd|ng.ait!that is not immediately affected by a dikurhanee or activity. AwpMibeks- Ope of two mtheral families which contain ashksKts minerals. rVmpiifeMashesroS tends to Ibnn in needi^dike shapes and inciudei trerholitei acunolite, wmchite, richterite, mtthophyllhe, crocidolke, and amosite asbestos C hysm le- Asbestos from the serpentine family of miner als. Chrysotile asbestos is flexible and historically a<> coonts;:ldr;;abdat95% of the aslxjstosfuisedi^ymercially :inthcIhiitedAtatcs.::^ii.::: .-'A "1.: ."A\. ""1 "A. . '.. .^nMr Risk~;Anyydmate of die probabil ity thar;a;person:maydevelop;cancer;excess of back- : ...ground ratessometime' ip,his:or herlifetime following 1!:iiexppsai^:rp api&fk&fe ; ... PCMB or Pima ContrastMicroscopy EquivalentTMPhase ' Cootrasr Microscopy I'CM); is the analytical method ibt asbestos used in occupational endrontnehtS- Cuctent health standards for asbestos ate based on studies which document the adverse health effects from asbestos , exposure in workers. Since the worker exposures used PGM, the health standards are based on the fibers which are connted In PGM.''Today, the EPA usesan analytical technique,Transmission Electron Microscopy orTEM, wltich catr seentudh lsmaler and thinner fibetx, -in order. to apply thTeutrent h e i d t ^ were counted using' aTEM analysis:the;EPA;used only those fibers which:would hay# beep .seen In the PCM;;; "; ' method and this equivabftr count of ;fihers; is called the ;;; Phase Contrast;Mibmscopy E ^aivatet or PCME. ;Eor this risk assessment, only those fibers which ate consulered to be. o f PCME-di memiens, greater:tban:3 microns ' ; in length, with at least a 3:1 length to width ratio, and as; diameter between {b25 nbctonsmidiS: mlcmMinplUsiv'e, were used. To give some idea of die size of a PCME fi- ' her; the average width o f a lummii hair is 80 microns: :;;;;; 95% UCL ar 95% Upper ConjMetm Limit o fthe Mean ~ A statistical calculation of the meyin cbneentration so that the actual mean will be less than this value 95% of the time. ............ ::' ;; Mmmfelwma A ;rare:cancer which.may affect;the;lining;;of the lungs (pleura) or the abdominal contents (perito neum), Most mesotheliomas are caused hy exposure to asbestos. Most cases of mesothelioma are diagnosed 30 years or more after the first exposure to asbestos. Site C ontacte Jadde Lane, S FD -3 Community involvement Coordinator LAS. EPA Region 9 ; 75 Hawthorne Street San Francisco, Ca 94105 ......: {415} 972-3236 or (800) 231-3075 jere Johnson* SFD-7-2 ;;;. Remedial projectManager . : ; : LAS. EPA Region 9 : :7 : ". ' 75 Hawthorne Street " ;. .... San Francisco, Ca 941(15 :...... . :: (415) 972-3094 or (800) 231-3075 : M a y 2 0 0 8 aumaTOwwwMWWwwmmmwwM^^ Page 9 Atlas Asbestos M ine Superfund Site ERA Releases Exposure a n d Risk Assessment for C le a r C reek M a n ag em e n t A rea Inform ation Repositories Coalmga District Library Si()5;;Nbitb ;... : C oaling^ /aO.3210 Kings; County Library 40i HorthDofoy Hanford, CA 93230 (551:582-026} M art Lutbesr K ing Library, 1 Washington Sjuare Safoseia95}92 : (408) 808-2000 information about the him is available on the internet at; : hrtp;//www.epa.gov/rcgion09/toxic/noa/cleatcreefe/; f t Printed on 30% Postconsum er Recycied/Recydabie Paper United States Environmental Protection Agency Region 9 75 Hawthorne Street (SFD-3) San Francisco, CA 94105 Attn: Jackie Lane {Atlas 5/08} Offidai Business Penalty for Private Use, $300 Address Service Requested FIRST-CLASS MAIL POSTAGE & FEES PAID U.S. EPA Permit No. G -35