5 Formaldehyde Exposure Limits Alberta Occupational Health and Safety Code 8-hour TWA OEL ppm Protect against carcinogenicity Ceiling limit – 2 ppm Protect against irritation of eyes, nose and upper respiratory tract
6 Formaldehyde Exposure Limits College of American Pathologists and College of Physicians and Surgeons of Alberta Accreditation Requirements: 8-hour TWA exposure limit ppm 8-hour TWA action level – 0.5 ppm 15 min STEL – 2 ppm Must be maintained below these levels in areas of Anatomic Pathology After initial monitoring, further monitoring is mandated if results equal or exceed 0.5 ppm ( action level) or 2 ppm STEL
7 Formaldehyde Exposure Limits College of American Pathologists and College of Physicians and Surgeons – Contd Initial 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 persons exposure Requires that monitoring be performed in accordance with Alberta Occupational Health & Safety Act, code and Regulations.
8 Formaldehyde 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, 4 th Edition (August 1994), …. including the 2 nd supplement (January 15, 1998), or (b) using methods or procedures that are approved by the Director of Occupational Hygiene….
9 Formaldehyde- Potential Exposure Incidents What Kind of Sampling / Measurement is Needed? TWA( 8 hour ) Short term (STEL) Ceiling limit
10 Formaldehyde- Potential Exposure Incidents
11 Formaldehyde- Potential Exposure Incidents
12 Formaldehyde- Potential Exposure Incidents
13 Formaldehyde- Potential Exposure Incidents
14 Formaldehyde- Measurement What measurement method is needed to measure Ceiling Limit exposures? What is available?
15 Formaldehyde 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, 4 th Edition (August 1994), …. including the 2 nd supplement (January 15, 1998), or (b) using methods or procedures that are approved by the Director of Occupational Hygiene….
16 Formaldehyde- NIOSH Methods NIOSH Method Description Max. Flow rate (L/min.) Min Volume (L) Min Time Detection Limit Minimum Concentration 2016 DNPH treated silica gel tubes- HPLC sec0.23 ug0.2 ppm 2541 HMP treated XAD-2 tubes-GC min3 ug2.7 ppm 3500 Impinger, bisulfite- colorimetric min2 ug1.8 ppm 3800 Extractive FTIR- direct reading NA 1 min to fill gas cell (Miran SapphIRe) 0.4 ppm (10 meter gascell) 0.4 ppm
17 Formaldehyde- Measurement No evaluated NIOSH methods were found suitable for Ceiling Limit formaldehyde measurement. Direct reading instrument must be used
18 Formaldehyde- Measurement Requirements of Direct Reading Instruments: Instrument method must be sensitive to 0.05 ppm Instrument 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 VOCs)
19 Formaldehyde- Measurement Requirements of Direct Reading Instrument – Contd: Data logging capability so that Ceiling Limit exceedances can be captured, then correlated to work log Method must be approved by Director of Occupational Hygiene- Alberta Occupational Health and Safety
20 Formaldehyde- 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
21 Formaldehyde- Interscan
22 Formaldehyde- Measurement Literature Review References for Interscan Instrument: Liu,F et al reported no statistical difference between Interscan 4160 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 Atmospheres ppm - mean difference was 3.5%, coeff. var
23 Formaldehyde- Measurement Literature Review References for Interscan Instrument Contd: NIOSH procedure RCT-APR-STP-0039, Determination of Formaldehyde Service Test Life, Air Purifying Respirators Standard Testing Procedure Mentions Interscan to give real time numbers in order to determine when formaldehyde breakthrough occurs in air purifying cartridges.
24 Formaldehyde- Measurement Literature Review References for Interscan Instrument Contd: US EPA Final Report IE 2814 Residential Indoor Air Formaldehyde Testing Program: Pilot Study Used 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 Leaks Gives specifications and performance criteria of direct reading instruments used in leak detection.
25 Formaldehyde- Interscan Method of function Electro-chemical voltametric sensor Electro-catalytic sensing electrode Sample pumped into instrument, then diffuses across medium to electrode Sensor electrolyte immobilized similar to electrolyte in alkaline batteries No problem with leakage, orientation of sensor, sensor noise Sealed reservoir eliminates reference electrode contamination Very linear response allows single point calibration over wide range
26 Formaldehyde- Interscan Sensitivity -0.1 ppm Accuracy ppm- mean difference was 3.5%, coeff. var Real Time Response? Almost immediate, <5 seconds Interferences? Minimal to other VOCs and alcohols, instrument drift reported
27 Formaldehyde- Interscan Data Logging Capability? Yes - with external data logger (ACR Systems SmartReader7) Approved by Director of Industrial Hygiene? No Request to Alberta Human Resources and Employment for approval of Interscan 4000 series for formaldehyde- Sep/06 Dec / 06 approval granted with conditions:
28 Formaldehyde Interscan Approval Conditions: Specific to Capital Health facilities Normal calibration is done at least quarterly when performing according to specifications within 35-65% RH. Recalibration required on regular basis when RH outside 35-65% Regular replacement of sensor due to reports of drift (manufacturer recommends quarterly or calibration check).
29 Formaldehyde- Interscan Test Trial Calibration performed at ALS Laboratories. 1 m 3 stainless steel calibration chamber Paraformaldehyde powder diluted with inert silica powder, preweighed amounts heated to vaporize formaldehyde in chamber. Formaldehyde concentrations measured by variety of methods.
30 Formaldehyde- Interscan Test Trial Formaldehyde concentrations measured by variety of methods: NIOSH DNPH treated silica gel tube--HPLC analysis NIOSH Impinger/bisulfite-chromotropic acid- colorimetry. Interscan 4000 Miran SapphIRe
31 Formaldehyde-Interscan Test Trial
32 Formaldehyde- Survey Results Location- Anatomical Pathology Lab- specimen preparation/ grossing. Workers- 2 histology technicians, one pathology assistant Samples collected- Six 8 hour TWA samples on each worker – NIOSH DNPH treated silica gel/ HPLC analysis Random / as-needed Ceiling Limit samples using Interscan 4000
34 Formaldehyde- Survey Results- GROSSING Ceiling / Activity Specific Instantaneous Interscan Readings DescriptionVentilation TypeAir Concentration (ppm) Grossing very large specimen Local hood0.050, 0.070, Placing large specimen back into storage bucket Local hood0.100 Grossing smaller specimen Local hood0.065 Returning specimen to container on floor General ventilation0.080 Removing fixed specimen from container Local hood0.04
35 Formaldehyde- Survey Results- GROSSING Ceiling / Activity Specific Instantaneous Interscan Readings DescriptionVentilation TypeAir Concentration (ppm) Grossing medium sampleLocal hood 0.045, 0.050, 0.060, 0.050, Returning medium sample to container-some splashing Local hood0.120 Grossing smaller specimenLocal hood0.040, Dumpling formalin into waste container General ventilation0.065 Removing fixed specimen from container Local hood0.055
36 Formaldehyde- Survey Results- GROSSING Ceiling / Activity Specific Instantaneous Interscan Readings DescriptionVentilation TypeAir Concentration (ppm) Removing medium sample from container Local hood0.065 Grossing medium specimenLocal hood0.060 Opening specimen transport box- some formalin spillage General only1.60 Removing endoscopy samples from plastic bags General only0.40, 0.65 Over garbage can (above plastic bags disposed of here) General only1.10, 0.45
37 Formaldehyde- Results- AUTOPSY SUITE Ceiling / Activity Specific Instantaneous Interscan Readings DescriptionVentilation TypeAir Concentration (ppm) Specimen disposal General only0.80, 1.60, >1.99 Over open bucket of discarded used specimens General only1.10 Room background- middle of autopsy suite, door closed General only0.25 Addition of formaldehyde neutralizer and stirring to neutralize waste General only0.45
38 Formaldehyde- Results- AUTOPSY SUITE Ceiling / Activity Specific Instantaneous Interscan Readings DescriptionVentilation TypeAir Concentration (ppm) Over open bucket of waste formalin General only<1.99 Over open bucket of deformalized formalin General only0.90 In specimen storage room-door open General only0.20 In specimen storage room-after door closed 1 minute General only0.45
39 Formaldehyde- Interscan Discussion: Interscan gave reliable, real-time information for formaldehyde concentrations TWA average samples indicated that average concentration was well below OELs However, Interscan identified activities/ tasks that exceeded or had potential to exceed Ceiling Limit OEL- very variable readings most likely log normally distributed with high standard deviation- highly skewed istribution
40 Formaldehyde- Interscan Discussion Contd: Added benefit: worker is shown in real time the consequences of performing certain activities, can make practice improvements can immediately reassess changes in exposures from performing improved procedures this is important in reducing exposures through education on chemical handling with Ceiling Limit OELs.
41 Acknowledgements Craig Hrynchuk - Senior Manager, Regional Occupational Health, Safety and Wellness, Capital Health Authority Chris Sheppard – Safety & Hygiene Consultant (formerly of Capital Health) Doug Linman - Safety & Hygiene Consultant