Formaldehyde Exposure Measurement at Capital Health

1
Formaldehyde Exposure Measurement at Capital
Health
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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

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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

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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.

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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.

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Formaldehyde- Potential Exposure Incidents

• What Kind of Sampling / Measurement is Needed?
• TWA( 8 hour )
• Short term (STEL)
• Ceiling limit

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Formaldehyde- Potential Exposure Incidents
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Formaldehyde- Potential Exposure Incidents
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Formaldehyde- Potential Exposure Incidents
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Formaldehyde- Potential Exposure Incidents
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Formaldehyde- Measurement

• What measurement method is needed to measure
  Ceiling Limit exposures?
• What is available?

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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.

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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 1.5 1 40 sec 0.23 ug 0.2 ppm
2541 HMP treated XAD-2 tubes-GC 0.1 1 10 min 3 ug 2.7 ppm
3500 Impinger, bisulfite- colorimetric 1.0 1 1 min 2 ug 1.8 ppm
3800 Extractive FTIR-direct reading NA NA 1 min to fill gas cell (Miran SapphIRe) 0.4 ppm (10 meter gascell) 0.4 ppm
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Formaldehyde- Measurement

• No evaluated NIOSH methods were found suitable
  for Ceiling Limit formaldehyde measurement.
• Direct reading instrument must be used

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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)

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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

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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

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Formaldehyde- Interscan
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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

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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.

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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.

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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

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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, lt5 seconds
• Interferences?
• Minimal to other VOCs and alcohols, instrument
  drift reported

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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

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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).

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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.

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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

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Formaldehyde-Interscan Test Trial
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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

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Formaldehyde- Survey Results

• TWA Sample Results

Description Sample Time (min.) Air Concentration (ppm)
Pathology Assistant 367 0.051
Histology Technician 456 0.11
Histology Technician 414 0.030
Area- specimen receiving 473 / 474 0.017 / 0.02
Area- grossing 471 0.02
Area- specimen storage 471 0.11
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Formaldehyde- Survey Results- GROSSING

• Ceiling / Activity Specific Instantaneous
  Interscan Readings

Description Ventilation Type Air Concentration (ppm)
Grossing very large specimen Local hood 0.050, 0.070, 0.070
Placing large specimen back into storage bucket Local hood 0.100
Grossing smaller specimen Local hood 0.065
Returning specimen to container on floor General ventilation 0.080
Removing fixed specimen from container Local hood 0.04
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Formaldehyde- Survey Results- GROSSING

• Ceiling / Activity Specific Instantaneous
  Interscan Readings

Description Ventilation Type Air Concentration (ppm)
Grossing medium sample Local hood 0.045, 0.050, 0.060, 0.050, 0.070
Returning medium sample to container-some splashing Local hood 0.120
Grossing smaller specimen Local hood 0.040, 0.045
Dumpling formalin into waste container General ventilation 0.065
Removing fixed specimen from container Local hood 0.055
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Formaldehyde- Survey Results- GROSSING

• Ceiling / Activity Specific Instantaneous
  Interscan Readings

Description Ventilation Type Air Concentration (ppm)
Removing medium sample from container Local hood 0.065
Grossing medium specimen Local hood 0.060
Opening specimen transport box- some formalin spillage General only 1.60
Removing endoscopy samples from plastic bags General only 0.40, 0.65
Over garbage can (above plastic bags disposed of here) General only 1.10, 0.45
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Formaldehyde- Results- AUTOPSY SUITE

• Ceiling / Activity Specific Instantaneous
  Interscan Readings

Description Ventilation Type Air Concentration (ppm)
Specimen disposal General only 0.80, 1.60, gt1.99
Over open bucket of discarded used specimens General only 1.10
Room background- middle of autopsy suite, door closed General only 0.25
Addition of formaldehyde neutralizer and stirring to neutralize waste General only 0.45
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Formaldehyde- Results- AUTOPSY SUITE

• Ceiling / Activity Specific Instantaneous
  Interscan Readings

Description Ventilation Type Air Concentration (ppm)
Over open bucket of waste formalin General only lt1.99
Over open bucket of deformalized formalin General only 0.90
In specimen storage room-door open General only 0.20
In specimen storage room-after door closed 1 minute General only 0.45
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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

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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.

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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

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Formaldehyde- Interscan
Questions?