Closed Face Cassette Wall Deposits Impact on Beryllium Sample Results

1
Closed Face Cassette Wall Deposits Impact on
Beryllium Sample Results

• Michael J. Brisson
• Washington Savannah River Company, Aiken, SC
• Chair, Beryllium Health and Safety Committee
• (BHSC)
• WSRC-MS-2008-00051-S
• March 6, 2008

2
Disclaimers

• Mention of commercial products in this
  presentation does not imply endorsement by the
  author, WSRC, or SRS.
• The findings and conclusions in this presentation
  are those of the author and do not necessarily
  represent the views of WSRC or SRS.
• Neither the speaker nor the BHSC speak for, or
  represent, DOE or any other federal agency.

3
Another Disclaimer

• I do not take a position in this presentation
  either for or against including wall deposits in
  air samples
• My goal is to explain the issue, impacts, and
  what is being done now by various groups
• Try not to anticipate my conclusions before I get
  to them in the presentation

4
Presentation Outline

• Introduction to Wall Deposits
• What they are and why it matters
• History on samplers and sampling
• History of wall deposits and exposure limits
• Recent data (Harper/Demange)
• Limitations
• Recent actions by OSHA, AIHA, and ASTM
• Revisions to analytical methods
• Lack of clear consensus
• What are DOE sites doing now?
• BHSC study, white paper, April discussion
• Possible options
• Do nothing
• Change sampling methods
• Change analytical methods
• Beryllium-specific impacts (10 CFR 850)

(Source Ashley, Brisson, and Jahn, Standardizatio
n Issues in Beryllium Sampling and Analysis,
presented at Pittcon 2006)
5
Introduction to Wall Deposits

• This is not a new issue
• Has been discussed since 1990
• This is not a beryllium-specific issue
• Affects all metal particulate sampling
• Hexavalent chromium, lead, etc.
• This is not a DOE-specific issue
• International issue
• Affects everyone measuring metal particulate in
  the workplace

6
Introduction to Wall Deposits

• What they are
• Particulate that enters sampling cassette and
  deposits on interior walls rather than on
  sampling medium (i.e., filter)
• Why it matters
• Worker is exposed to whatever particulate is in
  the air
• If the filter doesnt catch all the particulate,
  is the catch representative of the risk to the
  worker?

7
Historical Information

• Samplers
• Impingers
• Open face cassettes
• Closed face cassettes (CFC)
• Popular in U.S. but not internationally
• IOM sampler
• Intended to match up with ISO inhalable
  convention
• Popular in Europe but not U.S.
• Sampling
• Particulate mass is typically preferred metric
  for metals
• For Be, we measure mass but particle size and
  number may also be important (McCawley et al.,
  Appl. Occup. Environ. Hyg., 2001, 16631-638)

(SourceFermilab Web site, www-esh.fnal.gov)
8
Wall Deposits and Exposure Limits

• Particulate in general
• PEL for hexavalent chromium included wall
  deposits
• Many other PELs and/or TLVs, including beryllium,
  did not

9
ISO Conventions ISO 7708 (1995)

• International push to inhalable fraction
• Particles between 10-100 mm not efficiently
  sampled by CFC
• When CFC wall deposits included, more closely
  matches IOM (inhalable) performance
• ACGIH NIC for beryllium proposes inhalable
  fraction

THORACIC FRACTION Lung airways gas-exchange
region Median cut point 10 mm
RESPIRABLE FRACTION Gas exchange region Median
cut point 4 mm
INHALABLE FRACTION Entire respiratory
tract Median cut point 100 mm
10
Wall Deposits How Much?

• Varies widely
• Up to 127 of filter catch based on studies from
  1990-2002
• Varies from metal to metal
• Wind speed may add to variability
• Possible causes
• Electrostatic charges
• Inertia
• Gravitational settling
• Diffusion mechanisms
• There are concerns that people can inhale these
  particles and we arent measuring them

11
Recent Data

• Harper and Demange, Concerning sampler wall
  deposits in the chemical analysis of airborne
  metals, J Occup Environ Hyg 4D81-D86 (2007)
• Data shown on next two slides
• Very limited beryllium data (only 4 data points)

12
Recent Data (Harper/Demange) 37 mm CFC
13
Recent Data (Harper/Demange) IOM
14
So The Question Is

• WHAT IS THE SAMPLE???
• Filter catch only, or include wall deposits?
• Does the CFC collect the sample we need?
• Do the answers vary with the analyte(s) of
  interest?
• How do the answers impact sampling and analysis
  methods and costs?

15
Issues with Data Comparability

• Adding wall deposits would increase the mass of
  particulate being analyzed
• Does that invalidate the current PELs and TLVs
  that were based on filter catch only?
• How do we compare old and new data after
  making such a change?
• Should we avoid change or recognize we may need
  to change and take steps to manage it?

16
Recent Actions - OSHA

• Analytical method for Cr(VI), ID-215 Version 2
• Requires cassette walls to be wiped down
• Method has been validated with wall deposits
  wiped down
• Analytical method for metals, ID-125G
• OSHA lab wipes down cassette walls
• Method with wiping down walls NOT validated
• Beryllium PEL
• SBREFA report under development
• Unknown whether revised regulation will say
  anything about methods or wall deposits

17
Recent Actions AIHA

• Study by Sampling and Laboratory Analysis
  Committee, 2007
• Did not take a position either for or against
  including wall deposits in the sample
• Changes in methods need to be based on data
• Expected level (or range) of wall deposits
• Effectiveness of procedure to collect/include
  wall deposits
• Changes in methods should be addressed by
  standards bodies that own the methods (e.g.,
  OSHA, NIOSH, ASTM International)
• Laboratory QA Policy
• If standard methods not used as is
• Lab must state up front it is using a modified
  method
• Performance data required
• Thus, since OSHA ID-125G with wall deposits has
  not been validated, performance data could be
  required

18
Recent Actions ASTM International

• Subcommittee D22.04 on Workplace Air Quality
• New analytical methods advise users to determine
  whether the sample needs to include wall deposits
• Details provided in non-mandatory appendices
• Guidance provided on ways to include wall
  deposits
• This can be expected to be added to older
  standards as they are reviewed (once every five
  years)

19
The Upshot of These Actions

• Wall deposits are recognized as a significant
  issue
• No clear consensus on whether they should be
  considered part of the sample
• Additional evaluation and/or study seems called
  for
• Standards bodies need to evaluate their methods
• OSHA has clearly gone forward with including wall
  deposits
• Others have not gone that far or have not yet
  acted

20
What DOE Sites Are Doing (Beryllium)

• LLNL is including wall deposits
• Most others are not
• (Above based on anecdotal information, not on a
  formal survey. Corrections or updates would be
  welcomed.)

21
What the BHSC Is Doing

• Initial white paper now under development
• Describes overall issue and current status
• Discusses additional information needed
• Will NOT offer guidance or opinions
• Additional white paper(s) may be developed later
• Collection of additional beryllium-specific
  information identified as a research need

22
Options

• The following slides describe options that could
  be considered for the wall deposits issue. There
  may be other options.
• This assumes that a conclusion has been reached
  about what is the sample.
• This is intended to be beryllium-specific but may
  be applicable to some other metal particulates.

23
Filter Catch Only

• Do not include wall deposits in sample
• Potentially viable if
• Beryllium wall deposits are found to be low
  enough (reminder for the four data points
  available, median was 12 of filter catch and
  maximum was 39)
• A correlation can be established such that the
  filter catch can be deemed representative

24
Change Sampling Methods?

• Identify sampling methods that reduce amount of
  particulates on the walls
• Make cassette conductive
• Create aerodynamically smooth surface
• Decrease diameter of filtration area
• (Blackford et al., Ann Occup Hyg, 1985,
  29169-180)
• Use IOM sampler
• Cartridge serves as sample inlet, sealed to
  filter
• Also would follow inhalable convention
• Would have some cost impact and may require RD

25
Change analytical methods?

• Wipe interior walls of cassette and include with
  sample
• What OSHA does now
• Would require additional digestion volume could
  be a problem with lab reporting limits
• Would need to be validated (OSHA has not done so
  for Be)
• Would significantly increase analysis time and
  cost
• Rinse interior walls
• OSHA believes this is less effective than wiping
• Would need to be validated
• Develop a fully digestible sample capsule
• Would require RD (up-front cost)
• Would not necessarily increase analysis time/cost

26
Beryllium-Specific Impacts

• Including wall deposits
• Would likely increase beryllium levels found in
  at least some areas
• Possible increases in engineering controls, PPE,
  medical surveillance
• Would cause issues for the Beryllium Registry
• How to handle data
• Actually may already be an issue since some labs
  include wall deposits now
• Would have some cost impacts

27
Conclusions

• The wall deposits issue cannot be ignored
• It is bigger than DOE and will largely be
  addressed by others outside of DOE
• However, individuals can have a say by
  participating in standards bodies such as ASTM
  International
• The larger groups will not be as concerned about
  beryllium as DOE, and possibly DOD, will be
• Whatever is decided upon, should be applied
  consistently

28
Acknowledgements

• Melecita Archuleta (Sandia)
• David Weitzman (DOE-HQ)
• Paul Wambach (DOE-HQ)
• Martin Harper (NIOSH)
• Kevin Ashley (NIOSH)
• Burney Hook (SRS)
• Amy Ekechukwu (SRNL)
• Marc Kolanz (Brush-Wellman)
• Terry Civic (Brush-Wellman)
• Kenn White (Consultant)
• Other BHSC members

Thanks!
29
For More Information

• Mike Brisson
• Chair, BHSC
• 803-952-4400
• mike.brisson_at_srs.gov
• Melecita Archuleta
• Chair, BHSC Sampling and Analysis Subcommittee
• 505-845-9051
• melarch_at_sandia.gov