Industrial Hygiene Sampling Scenario – MT Cast Works Tasks • • Overall Objective: Develop an exposure monitoring plan, remember to consider all possible hazards by understanding the process be sure to o Define objectives of sampling strategy o Research contaminates ▪ Develop a health hazard evaluation o Determine your scope of work (protocol for each agent) ▪ SEGs Prepare a detailed sampling plan and submit in a report format citing all references appropriately Assumptions: • • • You are a new hire at Montana Cast Works. The previous sampling data are vague and therefore you don’t feel confident using it as a baseline You do not have a strict budget. You must however, consider cost when you determine the sampling strategy. You can freely select employees. Possible Sample Protocol Questions 1. 2. 3. 4. 5. 6. 7. 8. What is the goal of the sampling strategy? What data should be collected during each sampling campaign? Where should the samples be collected? How many workers should you sample? a. Are there SEG? When should the samples be collected? What collection technique should be used? What analytical techniques should be used? What data analysis methods should be used? Demographics Major work areas on shop floor • Wax Forms • Shell making • Hand finish • Welding • Supervisor Office Overall Process Lost Wax Process https://www.youtube.com/watch?v=Xeg575g_Cgs Wax form contains 2 (two) machines which form the wax shapes. The same workers either operate the machines or attach the different wax pieces on to a center tree with Paraffin Wax. https://www.youtube.com/watch?v=GcmAGz8WGWI. Twelve people work in this area on first shift. Shell Making: The wax forms are dipped into a large flask of sand. The sand is silica free. http://www.chinametalcastings.com/investment-casting-services. Six people work in this area, two on each shift. The hand finishers wipe the parts down to remove the dust with toluene throughout the process of removing burrs and imperfections from the cast parts. The process of finishing the product is similar to the one seen in the video https://www.youtube.com/watch?v=CvHFGy5Sn5s. The hand finish work is preformed within an environmental booth (dust collection booth). http://www.hydrotron.net/products/booths/. The booth is a designated a hearing conservation zone. Aluminum dust is generated during the hand finish process. Twelve people work in this area, four on each shift. Welding is the final process. Materials are jointed together with a Mig welder. Twenty people work in this area, twelve on days, 6 on second, and 3 on third. Six maintenance personal work at the facility, three on days and two on second and one on third shift. Each shift has a supervisor and a manager, supervisor offices are on the shop floor where as manager offices are not. The break room is separated from the industrial area by a door that is often left open. All workers wear safety glasses, steel toed shoes and gloves. Welders don positive pressure hoods. o First shirt: 8AM-4:30PM; o Second shift: 4PM:12:30AM o Third shift: 12AM -8:30AM 1. Montana Resources Industrial Hygiene Monitoring Plan 1.1. Objectives The goal of the monitoring plan is to investigate occupational exposures to inhalation and noise hazards during tasks associated with maintence workers perforking tasks in the Primary and Seconday Crushers and Mill Building. These results will be utilized to determin a exposure distribution, recommend hazard control strategies, assess OEL compliance. 1.2. Hazards Potential hazards associated with this facility and their respective regulated limits/levels are shown in Table I. Table I: Hazards Hazard Noise Noise Dust (repairable) Dust Repairable (quarts) Dust (total) Method OEL TWA Action Level and Hearing Conservation Ceiling Exchange Rate Value ACGIH (quarts) OSHA OSHA ACGIH Molybdenum OSHA Target Organ Method MSHA 90 dB Ear 85 dB 115 dB Ear 5 dB Eyes, respiratory .1 mg/m3 system 10 mg/m3 / %SIO2 + 2 Eyes, respiratory system 15 mg/m3 Eyes, respiratory 10 mg/m3 (less system 1% silica) 15 mg/m3 Eyes, respiratory system, liver, kidneys MSHA 7500 / 0600 7500/ 0600 0500 7300 and 7303 1.3. Sampling Demographic Ten workers will be selected to accommodate the class size and represent the three different work locations. All ten works will be sampled for noise, 2 workers for Molybdenum and 4 workers for total dust and 4 workers for repairable dust. Students will arrive at MT Resources at 6AM on 11 April to calibrate equipment, sampling will be being at approximately the beginning of the shift. At least one student from each group will return at a time convenient with MT Resources to check on the samples and again end at 3PM, to collect the samples. An estimated 8 hour sample period is expected. 2. Methods and Measurement 2.1. Dust Personal dust exposure will be assessed using NIOSH method 0500 for total dust and 7500 / 0600 for % silica and respirable fraction. Dust as full period single sampls (one 8 hour sample). Samples will be obtained using personnal air sampling pumps (pre and postcalibrated), connected with flexible to: • Alumunum cyclone and tared 37mm 5um PVC filter membrane filter, at a sample flow rate of 2.5 L/min. for % Silica and total dust respirable (PNO or particles not otherwise regulated) • A tared open face 37mm 5um PVC filter, at a flow rate of 1.7 lpm for Total Dust (PNO) Table III: Sampling Summary Hazard Dust (repairable) (quarts) Additional Total Samples Media 4 media Dust Repairable 2 blanks 2 back up 9 Included in above samples Dust (total) Method 4 media Molybdenum 1 media Molybdenum 1 media 2 blanks 2 back up 9 2 blanks 1 back up 2 blanks 1 back up 5 5 Methods Flow MSHA method deviation rate (lpm) 7500 2.5 V est = 1200 L V max NIOSH method V max = 1000L 0600 V est 1200 L NIOSH Method V max = 400L 0500 1.7 V est = 816 L NIOSH method V max method 133L 7300 1.7 V est 816 L NIOSH method V max 67L 7303 1.7 No deviation 2.2. Molybdenum Molybdenum exposure will be assessed using OSHA Method 7300 and 7303 as full period sample (one 8 hour sample). Samples will be obtained using personnal air sampling pumps (pre and post-calibrated), connected with flexible tubing to a 37mm cassett with a .8um MCE filter (open face) at a sample flow rate of 1.7 L/min. 2.3. Noise Ten noise samples will be collected according to MSHA Standards for TWA of 8 hours. The microphone was placed on the top of the shoulder, in the hearing zone of the employee, unobstructed by clothing. Edge 4 or Edge 5 dosimeters will be pre-calibrated at a level of 114 dB. Each dosimeter allowed for two separate settings--one for MSHA Hearing Conservation (HC) and the other for MSHA PEL. The HC criterion is set to 85 dB and the PEL to 90 dB, both have a 5 dB exchange rate. 2.4. Team assignments Table III shows the MT Tech teams and the methods they will be following. DUST A Ethan A Ciara B Kristopher B Jessica C Caitlin C Aris D Hali D Mark E Kylie E McKinley F Elizabeth F Dylan G Shandy G Ray G Natalie H Turk H Alicia Method Media Serial# 7500 1 7500 2 7500 3 7500 4 500 5 500 6 500 7 500 8 Blank 7500 9 Blank 7500 10 Blank 500 11 Blank 500 12 7300 11APR2017_M1 7303 11APR2017_M2 MOLYBDENUM - Mo I Zachary I Kayla J Abdullah J Molly Blank 11APR2017_M3 Blank 11APR2017_M4 Blank 11APR2017_M5 Blank 11APR2017_M6 Example 1. Introduction The XXX sampling is occurring to evaluate employee exposure to XXX utilized within the facility for XXX. These XX include: XXX. Since all of the solvents have relatively low flash points, vapor pressures and boiling points the solvents may present significant inhalation hazards. As such the sampling will concentrate on XXX in selected employees. While it is the hope the exposure levels are below the regulatory action levels it is the intent of management to achieve compliance with the strictest exposure limits feasible. 2. Agents of interest Table 1. Chemicals OSHA Exposure Limits NIOSH ACGIH Regulatory Action Limit Health Factors/ Target Organs Work Zone Used Table 1 describes the exposure limits, target organs, and general areas used for each solvent. Additional Information on each solvent can be found on XXXX 3. Operations/Facility Description 3. Employees Area 1st 4. Table 2 Shift 2nd Sample Plan/Strategy . 1 3rd Total Area Employees Example Table 3 identifies the number of employees to be sampled per shift and the total number of employee group full period consecutive samples to be collected for each solvent. Area 1st 5. Table 3 Shift 2nd 3rd Total Samples Sample Protocol & Analytical Methodology The sample protocol and analytical methodology for each solvent to be used is summarized in Table 6. Solvents of Interest 6. Table 6 Sample Protocol Analytical Methodology Outcomes While it is the hope the exposure levels are below the regulatory action levels it is the intent of management to achieve compliance with the strictest exposure limits feasible. If at any point an exposure is found above the regulatory action limit management shall evaluate the processes and equipment for potential improvements to reduce the exposures to below the regulatory action limit. If at any point an exposure is found above OSHA permissible exposure limits there will be an immediate, mandatory implementation in the use of respiratory personal protective equipment prior to further 2 Example processing. Once respiratory PPE is in place production shall commence again. The use of respiratory PPE will remain in effect until adequate engineering and administrative controls can be implemented, the sampling can be repeated and results show exposure levels below OSHA permissible exposure limits. 3 1 Exposure Assessment Part II Theresa Stack, MS, CSP, CPE Associate Professor 2/18/2020 Topics • Unusual Work Schedules • Additive and Independent Effects Unusual Work Schedules (UWS) • Workers on schedules significantly different from the conventional • 8-hour/day, 40 hr/week ▫ Adjustment is required to ▫ Provide protection equal to that provided to workers on conventional work shifts ▫ OSHA based on 8 hr days 40 hr wk; •OSHA ▫ http://www.osha.gov/OshDoc/data_Hurricane_Facts/faq_longhours.html •NIOSH ▫ http://www.cdc.gov/niosh/docs/2004-143/ 42 4 Decay of chemicals in the human body 2/18/2020 Chemical Determinant Timing Half-life (hours) Nickel In urine 24 Phenol In Urine 3.5 Polycyclic aromatic hydrocarbons In Urine 6-35 Sulfur Dioxide Toluene 6 mo In blood 5 Exhaled air 1.5-5 Unusual Work Schedule Models Adjusted OELs •Brief and Scala Model ▫maintain the same overall body burden yet preserve the same margin of safety as the original standard. The Occupational Environment -- Its Evaluation and Control 46 Unusual Work Schedule RF = REDUCTION FACTOR OEL is multiplied by RF for ADJUSTED OEL HR PER DAY RF = (8 / T) x {(24 - T) / 16} HR PER WEEK RF = (40 / T) x {(168 - T) / 128} Hrs/day unexposed Hrs/week unexposed T = actual hours worked by week and day Only variable Do both calculations The adjusted exposure limit is calculated using each equation and the most restrictive value adopted. 48 Unusual Work Schedule – Brief & Scala Daily Adjustments of Occupational Exposure Limits: • Daily Reduction Factor = (8/t) x {(24-t/16)} ▫ where t = actual hours worked per DAY Adjusted Exposure Limit = 8hr OEL x Daily Reduction Factor Weekly Adjustments of Occupational Exposure Limits: • Weekly Reduction Factor = (40/t) x {(168-t)/128} ▫ where t = actual hours worked per WEEK Adjusted Exposure Limit = 8hr OEL x Weekly Reduction Factor The adjusted exposure limit should be calculated using each equation and the most restrictive value adopted. Example Work place exposure to 1,2 trichloroethane Work schedule = 12 hr/day - 3 days/week ▫ ACGIH TLV and OSHA PEL = 10 ppm. What modified OEL would be appropriate for these workers? Daily Adjustments of Occupational Exposure Limits: • Daily Reduction Factor = (8/t) x {(24-t/16)} ▫ where t = actual hours worked per DAY Adjusted Exposure Limit = 8hr OEL x Daily Reduction Factor Weekly Adjustments of Occupational Exposure Limits: • Weekly Reduction Factor = (40/t) x {(168-t)/128} ▫ where t = actual hours worked per WEEK Adjusted Exposure Limit = 8hr OEL x Weekly Reduction Factor The adjusted exposure limit should be calculated using each equation and the most restrictive value adopted. 50 Unusual Work Schedule – Brief & Scala Equations 12 hours/day, 3 days/week | OEL 10 ppm HR PER DAY RF = (8 / T) x {(24 - T) / 16} HR PER WEEK RF = (40 / T) x {(168 - T) / 128} 48 12 hours/day, 3 days/week | OEL 10 ppm Daily Adjustments of Occupational Exposure Limits: • Daily Reduction Factor = (8/12) x {(24-12/16)} • DRF=.667 X .75 D-RF = .5 Adj. Exposure Limit = 8hr OEL x Daily Reduction Factor Adj OEL = 10 x .5 Adj OEL = 5 ppm Weekly Adjustments of Occupational Exposure Limits: • Weekly Reduction Factor = (40/36 )x {(168-36)/128} WRF = 1.11 x 1.03 W-RF = 1.13 NEVER INCRESE OEL Ta k i n g t h e c o n s e r v a t i v e a p p r o a c h the adjusted OLE is 5 ppm . 11 2/18/2020 Short Term Exposure Limit 12 STEL is a SHORT TERM EXPOSURE LIMIT 2/18/2020 An STEL is not a separate independent exposure limit, but supplements time-weighted average limits where there are recognized acute effects from a substance For example, STEL concentration is not acceptable if the TWA exceeds the OEL. Workers can be exposed to a maximum of four 15 minute STEL periods per 8 hour shift, with at least 60 minutes between exposure periods. 13 OEL = 8 ppm, STEL = 15 ppm 2/18/2020 Worker 1 Sample # PPM Time (min) 1_4Mar15_WS 10 60 2_4Mar15_WS 8 120 3_4Mar15_WS 15 30 4_4Mar15_WS 10 60 5_4Mar15_WS 5 120 6_4Mar15_WS 15 30 7_4Mar15_WS 1 70 14 2/18/2020 15 2/18/2020 PEL 8 PPM TWA 6.44 PPM Exposure Profile 16 14 12 PPM 10 8 6 4 2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Time (30 min) 2 STELs separated by at least 60 min AND TWA not exceeded 19 16 2/18/2020 Two or More Chemicals in the Work Place – additive effects AIHA Chapter 4 ~ Appendix A If it is reasonable to conclude that the chemicals present in the work place could add, one on the other, to the total affect then it is also reasonable to consider adding the exposure assessment to derive a total exposure. Additive effects for agents with similar toxicological effects DOI: 10.1520/STP634-EB 17 2/18/2020 Mixtures - Additive Effects Same target organ, similar toxicological effects Where 𝑇𝑉 = 𝐶1 𝑇𝐿𝑉1 + 𝐶𝑛 𝑇𝐿𝑉𝑛 C = Measured Concentration (actual) TLV = Threshold Limit Value or other OEL (allowed) TV = Total Value TV is the percentage of allowable dose The same formula as Severity previously seen a value of 1 = at the combined OEL 40 Additive Effects Example • Employees are exposed to the following, all target the organ systems: Chemical TWA  Benzene  Toluene  m-Xylene 0.1 ppm 40 ppm 40 ppm • Using the additive effects equation • Calculate the Total Value or percentage of the dose for this chemical mixture for OSHA and NIOSH 20 2/18/2020 TWA in PPM Benzene Toluene 0.1 40 OSHA OEL NIOSH OEL m-xylene 40 ACTUAL 1 200 100 ALLOWED 0.1 100 100 ALLOWED 𝑇𝑉 = Benzene Toluene M-xylene Total OSHA NIOSH 𝐶1 𝑇𝐿𝑉1 + 𝐶𝑛 𝑇𝐿𝑉𝑛 21 TWA in PPM Benzene Toluene 0.1 40 OSHA OEL NIOSH OEL m-xylene 40 ACTUAL 2/18/2020 1 200 100 ALLOWED 0.1 100 100 ALLOWED Benzene Toluene M-xylene Total OSHA .1 .2 .4 NIOSH 1 .4 .4 .7 70% 180% 22 2/18/2020 TWA in PPM Benzene Toluene m-xylene 0.1 40 40 ACTUAL OSHA OEL 1 200 100 ALLOWED NIOSH OEL 0.1 100 100 ALLOWED % dose = {(C1/L1) + (C2/L2) +…(Cn/Ln)} X 100 Benzene Toluene M-xylene Total % Dose OSHA 0.1 0.2 0.4 0.7 70 NIOSH 1 0.4 0.4 1.8 180 OSHA {(.1/1)+(40/200)+(40/100)} x 100= 70% NIOSH {(.1/.1)+(40/100)+(40/100)} x 100= 180% Mixtures - Independent Effects If mixture components are independent (not the same target organ) CANNOT SUM TWA instead evaluate SEVERITY ratio: TV= C/TLV Where C= Measured TWA concentration TLV = TLV for a substance or PEL TV = Total Value If ratio is < 1, exposure is less than OEL > 1, exposure exceeds the OEL* 39 Independent Effects Example • Employees are exposed to the following,  Toluene 25 ppm  Cotton Dust 0.1 mg/m3 • Using the Severity equation • Calculate the Total Value or percentage of the dose for each referencing the ACGIH TLV 25 2/18/2020 TWA Toluene 25 ppm Cotton Dust .1 mg/m3 ACTUAL ACGIH OEL 50 ppm .2 mg/m3 ALLOWED Total Value =TWA/OEL Toluene Cotton Dust 26 2/18/2020 TWA Toluene 25 ppm Cotton Dust .1 mg/m3 ACTUAL ACGIH OEL 50 ppm .2 mg/m3 ALLOWED Total Value =TWA/OEL Toluene 25/50 50% of dose Cotton Dust .1/.2 50 % of dose 27 2/18/2020 TWA Toluene 25 ppm ACGIH OEL 50 ppm 25/50=.50 50% of dose Cotton Dust .1 mg/m3 ACTUAL ALLOWED .2 mg/m3 .1/.2 = .50 50% of dose The exposures considered independently did not exceed acceptable limits Exposure Assessment and Sample Strategy Planning Sampling Strategy and Outline ◼ ◼ ◼ Understand a basic Sampling Strategy (SS) framework Consider protocols for each hazard (chemical, physical or biological) Judge exposure for SS modification 2 References ◼ ◼ The American Industrial Hygiene Association’s (AIHA) “Strategy for Assessing and Managing Occupational Exposures” DoD IH Enterprise Safety and Management System ◼ NIOSH Occupational Exposure Sampling Strategy Manual (PUB77-173) 3 *What is Screening To identify individuals or working populations with the propensity to develop a disease Screening ◼ Target diseases with a pre-clinical phase ◼ Detects disease or body dysfunction before an individual would normally seek medical care. ◼ Screening tests are usually administered to individuals without current symptoms, but who may be at high risk for certain adverse health outcomes. 2/18/2020 5 What is Monitoring the Worker To identify individuals or working populations that exhibit early signs of occupational disease or the propensity to develop a disease based on Risk Factors Surveillance - Medical / Exposure ◼The purpose is to detect early signs or to discover trends ◼Surveillance may use results from Screening ◼ A prevention focus 2/18/2020 6 Biological Monitoring of the Worker ◼ Biological Monitoring ◼ Measurement and assessment of substance or their metabolites in biological media to evaluate exposure or risk ◼ Body burden levels Other types of Monitoring? ◼ Biomarkers of exposure and effect ◼ A Closer look at dose Blood Lead Levels 2/18/2020 8 Sampling is Exposure Monitoring the Worker ◼ Exposure Monitoring ◼ Measurements (estimates of personal exposure) of concentrations of a substance in work environments ◼ Surrogate for dose 2/18/2020 9 Sampling Strategy and Exposure Model 1 Define Scope of Support and Resources 2 Basic Characterization 3 Establish SEG 4 Develop Workplace Monitoring Plan 5 Characterize Exposures 6 Assess Exposures and Provide Control Plan 7 Reporting & Recording 8 Re-Evaluation Define objectives Health Hazard Evaluation Protocol for specific campaign (s) Corporate Data Analysis 10 Exposure Model Establish SEGs Start Basic hazard Characterization Reporting and documentation Exposure Assessment Establish Monitoring / Sampling Strategy Acceptable Exposure Uncertain Unacceptable Exposure Control Further Information Gathering Reassessment 11 Modify Monitoring plan Exposure Model Steps 1-3 ◼ 1) Start - Define Objectives and Scope ◼ Why are you sampling, what needs to be accomplished? ◼ 2) Basic Characterization – ◼ Identify processes hazards, high-risk workers, and controls associated with those processes. ◼ 3) Establish Similar Exposure Groups – ◼ group workers who are performing like processes to allow the industrial hygienist to perform risk assessments for hazards and exposures for the group. 12 2/18/2020 13 Control Anticipation Recognition Evaluation Sampling Strategy Solvent Exposure Routes Symptoms Target Organs Ethyl Acetate Inhalation, ingestion, skin and/or eye contact Irritation eyes, skin, nose, throat; narcosis; dermatitis Eyes, skin, respiratory system Solvent Ehtyl Acetate Solvent OSHA PEL 400 ppm Boiling Point ACGIH TLV 400 ppm Flash Point ACGIH STEL NA LEL – UEL NIOSH REL 400 PPM NIOSH STEL NA Vapor Pressur e Vapor density Ehtyl Acetate 14 GHS Hazard Class Steps 4-6 ◼ 4) ◼ ◼ Develop Workplace Monitoring Plan – develop, and track a master schedule of surveys and assessments Protocol For each agent ◼ 5)Characterize ◼ ◼ 6) ◼ Exposures – Sampling Results and Characterization Assess Exposures and Provide Control Plan – compare exposures to occupational exposure limits (OEL) or expected adverse health effects, and determine the need for corrective actions and follow-up surveillance. 15 Steps 7-8 ◼ 7) Reporting and Recording – ◼ Develop and compile reports for briefing ◼ record exposures, conditions, and recommendations ◼ identify exposures and medical surveillance recommendations; and ◼ provide Occupational Medicine with an exposure summary for the medical records of each exposed worker. ◼ ◼ 8) Re-evaluation – ◼ repeat the exposure assessment process to improve previous assessments and reduce risk. 16 Exposure Model Establish SEGs Start Basic hazard Characterization Step 1: Basic Characterization and Objective Identification Reporting and documentation Exposure Assessment Establish Monitoring / Sampling Strategy Acceptable Exposure Uncertain Unacceptable Exposure Control Further Information Gathering Reassessment 17 Modify Monitoring plan Anticipation and Recognition of Hazards 18 Basic Characterization of SEG Abrasive Blasting ◼ In a large scale aircraft maintenance, repair and overhaul facility, aircraft landing gear components undergo three primary metalworking processes. ◼ Metal preparation Abrasive blasting ◼ Acid / Alkali cleaning ◼ Degreasing ◼ ◼ Metal fabrication ◼ ◼ Machining Metal finishing Thermal spray ◼ Electroplating ◼ Painting ◼ Abrasive blasting booth Basic Characteristics of SEG Understand hazards and process ◼ Components are electroplated w/ cadmium during metal finishing. ◼ ◼ Cadmium is highly toxic and exposure to this metal is known to cause cancer and targets the body's cardiovascular, renal, gastrointestinal, neurological, reproductive, and respiratory systems. Requirements to protect workers from cadmium exposure are addressed in specific OSHA cadmium standards covering general industry (1910.1027), shipyards (1915.1027), and construction (1926.1127)). ◼ Airborne emissions are present in the blast shop during abrasive blasting ◼ Utilizing a hand-operated nozzle to control a high pressure air stream of abrasive glass and plastic bead, media is directed onto the surface of the part generating fine particulate matter of media and cadmium. ◼ Blasting with operators directly inside of booth and external to booth with a glove box Abrasive blasting booth 21 22 Step 1:Define Scope Define Scope Identify organizations / areas to be Served Capture Demographics Schedule Visits 23 Begin to define objectives Anticipation Meet with Customers Step 1:Define Scope Define Scope Identify organizations / areas to be Served Capture Demographics Schedule Visits 24 24 Begin to define objectives Anticipation Meet with Customers Abrasive Blasting Example Basic Characterization ◼ Cadmium becomes airborne during basting operations as well as contaminates the spent blasting media ◼ ◼ ◼ Met Corporate and Blasting Division Supervisor Demographics: 14 full time workers - primary task is media blasting over 2 shifts Site visit found: PPE being used, Media capture system present, Dust present outside of the blasting booth, Prior IH sampling Preliminary objective: Ensure engineering controls are sufficient to limit exposure to the lowest possible dose. Monitor for secondary contamination. Abrasive blasting booth Abrasive Blasting Example Define Scope ◼Cadmium becomes airborne during basting operations as well as contaminates the spent blasting media ◼Objectives: Ensure that engineering controls are sufficient to limit exposure to the lowest possible dose. Monitor for secondary contamination. Abrasive Blasting Example: Basic Characterization ◼ Review workplace monitoring: Data for air monitoring shows potential overexposure to cadmium emitted during AB operations. ◼ ◼ TWA’s exceed OSHA AL 2.5 ug/m3 and PEL 5 ug/m3 Wipe sample data indicates cadmium inside of shop but outside of AB area ◼ ◼ ◼ ◼ ◼ ◼ Both are concerns for OSHA compliance Gap in effectiveness identified between engineering and administrative controls Data collected yearly from 2007 Samples collected by a CIH Samples analyzed by an accredited lab Supervisor and all AB workers informed of results 27 Abrasive Blasting Example: Basic Characterization ◼Review workplace controls: ◼ Downdraft system ◼ Qualitative assessment used as part of the exposure assessment ◼ Review Work Practices: ◼ PPE, Exposure assessment is a comprehensive task Respiratory Protection, Decontamination, Laundered Uniforms, OSHA regulated areas, Housekeeping, Hazardous Waste Management, PM, Training 28 Ex. Process and Engineering Controls Recognition 29 Recognition PPE and Work Practices 31 Step 2: Basic Characterization Basic Characterization ID Potential Exposures Assess Hazard Sources Describe Hazard Source Characteristics Describe Existing Controls Collect Source Emission Data Qualitatively Assess Review Previous Workplace Assessment Review Workplace Monitoring Plans Review Medical Surveillance Illness/Injury Data Meet Supervisor and Employee Rep Update Demographic Gaps ID/Inventory Hazard Sources Recognition Establish SEG Associate Processes To possible SEGs Step 3: Establish SEGs Evaluate the Exposure Profile and Work Practices (possible SEG) 33 Identify Personnel both Representative and High Exposure Recognition Establish SEG Associate Processes To SEGs AB in downdraft booth and glove box Establish SEGs ID Personnel both Representative and Potentially high exposure Evaluate the Exposure profile Workers cross trained and all perform same tasks 34 14 workers, two 2 shift, 40 hr weeks same work load – all workers representative 12 first 2 second 4) Develop Workplace Monitoring Plan Develop Workplace Monitoring Plan Protocols for Each Hazard Chemical Physical Biological Protocols for each Hazards Methods of evaluation Planning 35 4) Develop Workplace Monitoring Plan ◼ Data needed in the plan includes: ◼ Demographics (possible SEGs) ◼ Procedures for measuring exposures or controls ◼ Methods, media type, calibration ◼ Number of measurements (samples) ◼ Location (s) sampled ◼ Conditions required for monitoring ◼ Standards used to compare to results ◼ Data analysis procedures 36 4) Develop Workplace Monitoring Plan ◼ Procedures for measuring exposures or controls ◼ Methods, ◼ media type, calibration Number of subjects RANDOM SAMPLING OF A HOMOGENOUS RISK GROUP NIOSH Pub 77-173 N = original equal risk group size n = sub group size N =N if N3), this may be an indication that either the SEG is not properly defined or the process is out of control. The industrial hygienist should determine if this is the case and, if so, adjust the definition of the SEG to decrease the variability and collect any additional exposure monitoring data required. (f) Estimating the exposures in the upper tail. For determining what Exposure Effect Rating category describes a SEG, focus on the 95th percentile exposure in the upper tail. These upper tail values are used to assess exposures that are compared to 8-hour TWA-OELs, STEL-OELs, and Ceiling-OELs and are what the Navy currently uses. The Industrial Hygiene Statistics Spreadsheet supplied with reference 4-1 may be used. This is an Excel® spreadsheet and requires the user to have Microsoft Excel® installed on their computer to run it. Another alternative is to calculate parameters using DOEHRS-IH SEG Assessment. 1. Determine the 95th percentile exposure 2. Determine the UTL95%,95%. 3. Determine the exceedance fraction/probability of noncompliance. 4-21 4. Determine the one-sided 95% upper confidence limit (UCL1,95%) for the exceedance fraction/probability of noncompliance. (g) Refining a SEG's Working Exposure Assessment. The industrial hygienist is reminded that statistics are an aid to decision making and that the ultimate decision should be based on a combination of professional judgment and statistics. The results of exposure monitoring are fed back into the exposure assessment process at the basic characterization step. The following are guidelines for revising the Working Exposure Assessment based on exposure monitoring results of 6 or more randomly collected samples when compared to a Navy OEL, which is an 8-hour TWA, a STEL, or a Ceiling value: 1. If the 95th percentile exposure point estimate is greater than the OEL, the exposures may be unacceptable. Professional judgment along with all available information should be used by the industrial hygienist to make a final determination. For a SEG with an unacceptable exposure, controls may be instituted without additional sampling p...
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