5Formaldehyde Exposure Limits Alberta Occupational Health and Safety Code8-hour TWA OEL ppmProtect against carcinogenicityCeiling limit – 2 ppmProtect against irritation of eyes, nose and upper respiratory tract
6Formaldehyde Exposure Limits College of American Pathologists and College of Physicians and Surgeons of Alberta Accreditation Requirements:8-hour TWA exposure limit ppm8-hour TWA action level – 0.5 ppm15 min STEL – 2 ppmMust be maintained below these levels in areas of Anatomic PathologyAfter initial monitoring, further monitoring is mandated if results equal or exceed 0.5 ppm ( action level) or 2 ppm STEL
7Formaldehyde Exposure Limits College of American Pathologists and College of Physicians and Surgeons – Cont’dInitial monitoring must be repeated anytime change in production, equipment, process, personnel, or control measures which may result in new or additional exposure to formaldehyde.Periodic monitoring is mandated only if the initial monitoring is at or exceeds 0.75 ppm (8 hour TWA) or 2 ppm ( STEL).If any personnel report signs or symptoms of respiratory or dermal conditions associated with formaldehyde exposure, the laboratory must promptly monitor the affected person’s exposureRequires that monitoring be performed in accordance with Alberta Occupational Health & Safety Act, code and Regulations.
8Formaldehyde Exposure Limits Alberta Occupational Health and Safety Code , Part 4 Chemical Hazards, Biological Hazards and Harmful Substances 20(1):‘If a person measures the airborne concentration of a harmful substance for the purposes of complying with the occupational exposure limits as required by the Code, the person must make the measurement(a) in accordance with the NIOSH Manual of Analytical Methods, 4th Edition (August 1994), …. including the 2nd supplement (January 15, 1998), or(b) using methods or procedures that are approved by the Director of Occupational Hygiene….”
9Formaldehyde- Potential Exposure Incidents What Kind of Sampling / Measurement is Needed?TWA( 8 hour )Short term (STEL)Ceiling limit
14Formaldehyde- Measurement What measurement method is needed to measure Ceiling Limit exposures?What is available?
15Formaldehyde Exposure Limits Alberta Occupational Health and Safety Code , Part 4 Chemical Hazards, Biological Hazards and Harmful Substances 20(1):‘If a person measures the airborne concentration of a harmful substance for the purposes of complying with the occupational exposure limits as required by the Code, the person must make the measurement(a) in accordance with the NIOSH Manual of Analytical Methods, 4th Edition (August 1994), …. including the 2nd supplement (January 15, 1998), or(b) using methods or procedures that are approved by the Director of Occupational Hygiene….”
16Formaldehyde- NIOSH Methods DescriptionMax. Flow rate (L/min.)Min Volume (L)Min TimeDetection LimitMinimum Concentration2016DNPH treated silica gel tubes- HPLC1.5140 sec0.23 ug0.2 ppm2541HMP treated XAD-2 tubes-GC0.110 min3 ug2.7 ppm3500Impinger, bisulfite- colorimetric1.01 min2 ug1.8 ppm3800Extractive FTIR- direct readingNA1 min to fill gas cell (Miran SapphIRe)0.4 ppm (10 meter gascell)0.4 ppm
17Formaldehyde- Measurement No evaluated NIOSH methods were found suitable for Ceiling Limit formaldehyde measurement.Direct reading instrument must be used
18Formaldehyde- Measurement Requirements of Direct Reading Instruments:Instrument method must be sensitive to 0.05 ppmInstrument must be accurate (±25% of true reading 95% of time- NIOSH/OSHA criteria)Instrument method must be able to take readings in as close to real time as possible (~ 10 second response time or less)Instrument method must be free of other interferences (formalin contains a high proportion of methanol, health care has many other background VOC’s)
19Formaldehyde- Measurement Requirements of Direct Reading Instrument – Cont’d:Data logging capability so that Ceiling Limit exceedances can be captured, then correlated to work logMethod must be approved by Director of Occupational Hygiene- Alberta Occupational Health and Safety
20Formaldehyde- Measurement Direct Reading Instruments Available:Formaldemeter - poor response and interference from methanol and other oxidizable VOCs.CEA Instruments - very sensitive, too slow response to give real time, potential interferences.Miran sapphIRe - 1 minute cell fill time, not real time instrument, limited sensitivity, interferences.Detector tubes (Dragar, Gastec)- too slow response to give real time, poor sensitivity
22Formaldehyde- Measurement Literature Review References for Interscan Instrument:Liu,F et al reported no statistical difference between Interscan and a phenol reagent method (J. Env. Health., Vol 20, No.2, 2003.)NCASI Technical Bulletin 579 Laboratory and Field Evaluation of a Portable Continuous Analyzer for Measurement of Formaldehyde in Workplace Atmospheresppm - mean difference was 3.5%, coeff. var
23Formaldehyde- Measurement Literature Review References for Interscan Instrument Cont’d:NIOSH procedure RCT-APR-STP-0039, Determination of Formaldehyde Service Test Life, Air Purifying Respirators Standard Testing ProcedureMentions Interscan to give “real” time numbers in order to determine when formaldehyde breakthrough occurs in air purifying cartridges.
24Formaldehyde- Measurement Literature Review References for Interscan Instrument Cont’d:US EPA Final Report IE 2814 Residential Indoor Air Formaldehyde Testing Program: Pilot StudyUsed Interscan for real time formaldehyde measurements in conjunction with integrated sampling methods for building material off-gassing testing.US EPA Method 21 Determination of Volatile Organic Compound LeaksGives specifications and performance criteria of direct reading instruments used in leak detection.
25Formaldehyde- Interscan Method of functionElectro-chemical voltametric sensorElectro-catalytic sensing electrodeSample pumped into instrument , then diffuses across medium to electrodeSensor electrolyte immobilized similar to electrolyte in alkaline batteriesNo problem with leakage, orientation of sensor, sensor noiseSealed reservoir eliminates reference electrode contaminationVery linear response allows single point calibration over wide range
26Formaldehyde- Interscan Sensitivity-0.1 ppmAccuracyppm- mean difference was 3.5%, coeff. varReal Time Response?Almost immediate, <5 secondsInterferences?Minimal to other VOC’s and alcohols, instrument drift reported
27Formaldehyde- Interscan Data Logging Capability?Yes - with external data logger (ACR Systems SmartReader7)Approved by Director of Industrial Hygiene?NoRequest to Alberta Human Resources and Employment for approval of Interscan 4000 series for formaldehyde- Sep/06Dec / 06 approval granted with conditions:
28Formaldehyde Interscan Approval Conditions:Specific to Capital Health facilitiesNormal calibration is done at least quarterly when performing according to specifications within 35-65% RH.Recalibration required on regular basis when RH outside %Regular replacement of sensor due to reports of drift (manufacturer recommends quarterly or calibration check).
29Formaldehyde- Interscan Test Trial Calibration performed at ALS Laboratories.1 m3 stainless steel calibration chamberParaformaldehyde powder diluted with inert silica powder, preweighed amounts heated to vaporize formaldehyde in chamber.Formaldehyde concentrations measured by variety of methods.
30Formaldehyde- Interscan Test Trial Formaldehyde concentrations measured by variety of methods:NIOSH DNPH treated silica gel tube--HPLC analysisNIOSH Impinger/bisulfite-chromotropic acid- colorimetry.Interscan 4000Miran SapphIRe
34Formaldehyde- Survey Results- GROSSING Ceiling / Activity Specific Instantaneous Interscan ReadingsDescriptionVentilation TypeAir Concentration (ppm)Grossing very large specimenLocal hood0.050, 0.070, 0.070Placing large specimen back into storage bucket0.100Grossing smaller specimen0.065Returning specimen to container on floorGeneral ventilation0.080Removing fixed specimen from container0.04
35Formaldehyde- Survey Results- GROSSING Ceiling / Activity Specific Instantaneous Interscan ReadingsDescriptionVentilation TypeAir Concentration (ppm)Grossing medium sampleLocal hood0.045, 0.050, 0.060, 0.050,Returning medium sample to container-some splashing0.120Grossing smaller specimen0.040, 0.045Dumpling formalin into waste containerGeneral ventilation0.065Removing fixed specimen from container0.055
36Formaldehyde- Survey Results- GROSSING Ceiling / Activity Specific Instantaneous Interscan ReadingsDescriptionVentilation TypeAir Concentration (ppm)Removing medium sample from containerLocal hood0.065Grossing medium specimen0.060Opening specimen transport box- some formalin spillageGeneral only1.60Removing endoscopy samples from plastic bags0.40, 0.65Over garbage can (above plastic bags disposed of here)1.10, 0.45
37Formaldehyde- Results- AUTOPSY SUITE Ceiling / Activity Specific Instantaneous Interscan ReadingsDescriptionVentilation TypeAir Concentration (ppm)Specimen disposalGeneral only0.80, 1.60, >1.99Over open bucket of discarded used specimens1.10Room background- middle of autopsy suite, door closed0.25Addition of formaldehyde neutralizer and stirring to neutralize waste0.45
38Formaldehyde- Results- AUTOPSY SUITE Ceiling / Activity Specific Instantaneous Interscan ReadingsDescriptionVentilation TypeAir Concentration (ppm)Over open bucket of waste formalinGeneral only<1.99Over open bucket of ‘deformalized’ formalin0.90In specimen storage room-door open0.20In specimen storage room-after door closed 1 minute0.45
39Formaldehyde- Interscan Discussion:Interscan gave reliable, real-time information for formaldehyde concentrationsTWA average samples indicated that average concentration was well below OEL’sHowever, Interscan identified activities/ tasks that exceeded or had potential to exceed Ceiling Limit OEL-very variable readingsmost likely log normally distributed with high standard deviation- highly skewed istribution
40Formaldehyde- Interscan Discussion Cont’d:Added benefit:worker is shown in real time the consequences of performing certain activities,can make practice improvementscan immediately reassess changes in exposures from performing improved proceduresthis is important in reducing exposures through education on chemical handling with Ceiling Limit OELs.
41AcknowledgementsCraig Hrynchuk - Senior Manager, Regional Occupational Health, Safety and Wellness, Capital Health AuthorityChris Sheppard – Safety & Hygiene Consultant (formerly of Capital Health)Doug Linman - Safety & Hygiene Consultant