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Formaldehyde Exposure Measurement at Capital Health

Formaldehyde Exposure Measurement at Capital Health. Formaldehyde - Introduction. Formaldehyde uses at Capital Health: Pathology Morgue Tissue preservation. Formaldehyde - Introduction. Tissue Preservation 10% buffered neutral formalin Volumes used 20 ml to 20 L.

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Formaldehyde Exposure Measurement at Capital Health

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  1. Formaldehyde Exposure Measurement at Capital Health

  2. Formaldehyde - Introduction Formaldehyde uses at Capital Health: • Pathology • Morgue • Tissue preservation

  3. Formaldehyde - Introduction Tissue Preservation • 10% buffered neutral formalin • Volumes used 20 ml to 20 L

  4. Formaldehyde-Introduction Tissue Preservation - Pathology

  5. Formaldehyde Exposure Limits Alberta Occupational Health and Safety Code • 8-hour TWA OEL- 0.75 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- 0.75 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 – Cont’d • 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 person’s 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, 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….”

  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, 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….”

  16. Formaldehyde- NIOSH Methods

  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 VOC’s)

  19. Formaldehyde- Measurement Requirements of Direct Reading Instrument – Cont’d: • 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 • 0.3 - 8 ppm - mean difference was 3.5%, coeff. var. 0.01-0.06

  23. Formaldehyde- 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 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 Cont’d: • 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 • - 0.3 -8 ppm- mean difference was 3.5%, coeff. var. 0.01-0.06 Real Time Response? • Almost immediate, <5 seconds Interferences? • Minimal to other VOC’s 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 m3 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 2016- DNPH treated silica gel tube--HPLC analysis • NIOSH 3500- 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 2016- DNPH treated silica gel/ HPLC analysis • Random / as-needed Ceiling Limit samples using Interscan 4000

  33. Formaldehyde- Survey Results TWA Sample Results

  34. Formaldehyde- Survey Results- GROSSING Ceiling / Activity Specific Instantaneous Interscan Readings

  35. Formaldehyde- Survey Results- GROSSING Ceiling / Activity Specific Instantaneous Interscan Readings

  36. Formaldehyde- Survey Results- GROSSING Ceiling / Activity Specific Instantaneous Interscan Readings

  37. Formaldehyde- Results- AUTOPSY SUITE Ceiling / Activity Specific Instantaneous Interscan Readings

  38. Formaldehyde- Results- AUTOPSY SUITE Ceiling / Activity Specific Instantaneous Interscan Readings

  39. Formaldehyde- Interscan Discussion: • Interscan gave reliable, real-time information for formaldehyde concentrations • TWA average samples indicated that average concentration was well below OEL’s • 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 Cont’d: • 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

  42. Formaldehyde- Interscan Questions?

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