�ݺ�ߣ

Chemical
Safety Levels:
A tool whose
time has come?

R. Stuart

Laboratory Risk
Assessment
- or -
Who Needs a
Hood?
Ralph Stuart, Univ of Vermont

The Laboratory Safety Challenge

 Ever-evolving chemical selection and
process
 Lab walls are getting thinner, both
figuratively and literally
 Turnover – 20% per year in academia
 The educational culture currently
doesn’t include risk assessment:
but it can

Stakeholders in
Laboratory Risk Assessment

  Laboratory workers (personal safety
and efficient work)

  Laboratory upper management
(financial and carbon issues)

  Laboratory designers (design choices)
  Laboratory building operators (personal
safety and operations costs)

  Emergency responders (emergency
planning and response)

Emerging Issues in Lab Risks
  Ventilation design and energy costs
  Optimum ACH
  Hood design goals
  Building operation
  Protection of maintenance staff
  Building operations costs
  Education of lab staff about their buildings
  Re- and retro- commissioning
  Emergency planning and response
  Pre-plans
  Scene assessment
  Response rate: 1 emergency response/250 lab-years
  Do these challenges point the way from risk
assessment to control banding?
  Addressing these issues requires development ofbroader
understanding and language for lab chemical risks

Lab Planning and Design:
Moving beyond Tradition
  The traditional engineering approach uses a lot of
energy without much thought

  Control Banding:
Define Chemical Safety Levels from 1 to 4

  For many purposes, the control band deals with a
collection of chemicals rather than a specific
biological agent

  The result is a general guideline to appropriate
protections (which is likely to need modification, e.g
CSL 2+)

Chemical Risk Assessment

  Flammability
  Concentrations of concern tend to be a few percent by
volume

  Corrosivity
  Particles with kinetic energy are much harder to control
than vapors

  Reactivity
  Requires chemical and process specific literature review

  Toxicity
  Concentrations of concern range
from 1000 ppm to 0.5 ppm to ALARA

  GHS will help this process

Chemical Protection Strategies

  Change the chemical – limited opportunities in
the research setting
  Engineering controls
  General Ventilation
  Flammable cabinets
  Local Ventilation
  Chemical Hoods

  Administrative Controls and Oversight
  20% turnover/year in academic labs

  Personal Protective Equipment
  Traditionally, in chemistry laboratories,
fume hood + PPE = “as safe as can be”

Factors to Consider in Selecting a CSL:
  Flammability (via MSDS):
  check flashpoint (is it below ambient temperature?)
  If yes, are expected airborne concentrations above LEL?
 Corrosivity (via pH of solutions):
  pHs < 2 or > 10.5 require special handling
  Consider alsos spattering and off-gassing from reactions
 Reactivity (via MSDS and literature review)
  Check potential interactions and contamination concerns
 Toxicity (via MSDS and other sources)
  Review PELs, TLVs, IDLHs and assess against anticipated
concentrations
  Consider potential interactions
  ALARA for irreversible hazards (cancer, birth defects,
sensitization)

Conceptual Chemical Safety Levels

  CSL-1: no ventilation
(e.g. cold rooms and warm rooms)
  Chemical uses similar to residential settings
(kitchens and cleaning products)
  CSL-2: general ventilation
(X air changes/hour)
  Chemical uses similar to cars (gallons of
flammables and assorted other chemicals)
  CSL-3: local ventilation (i.e. hoods)
  Chemicals similar to hardware stores –
emergency concerns is unexpected reactions
  CSL-4: high hazard storage or processes that
require specialized procedures

Determining the CSL

Hazard Fire Corrosivity Reactivity Toxicity

CSL 1 Flashpoint 2 < pH < 10.5 No chemical changes All chemicals have
below ambient expected in the process known toxicities and
TLV’s > 500 ppm

CSL 2 Flashpoint near pH <2 or No known All chemicals have
ambient, pH >10.5 incompatibilities between known toxicities and
expected chemicals being used 10 ppm <TLV’s <
concentration < 500 ppm
10% LEL

CSL 3 Expected Use of heated Chemicals with known Unknown toxicities
concentration > corrosives reactions or or OEL < 10 ppm
10% LEL contamination hazards
present

CSL 4 High hazard reactions in Irreversible toxicities
use require use of
designated areas

But don’t forget the other pieces
of the control puzzle

Facility Personal Protective Oversight Emergency
Equipment Response
CSL 1 Any room, no None Generic self Standard
ventilation inspection response
guidelines

CSL 2 Ventilated lab room Nitrile gloves, eye General Fire response
(X ACH) protection training and
oversight

CSL 3 Lab room with local Appropriate gloves, eye Process Hazmat
ventilation (fume protection, lab coats specific defensive
hood) training and response ->
protocols commercial
clean-up
CSL 4 Specifically designed Process specific PPE Written SOPs Specialized
lab and specific hazmat
oversight response
practices

Implementation at the lab level:
A Risk Assessment Spreadsheet

At the Campus Level,
CSL’s can be used to:

  Establish an inventory of laboratory rooms
in place
  Preliminary estimate for non-chemistry
buildings, 75% CSL 2 labs
  Support design standards for new and
renovated lab settings.
  Improve training and emergency planning.
  Support communication between lab
workers and facility and emergency support
services.
  Plan for climate actions appropriate to the
campus.

Next Steps

 Complete a risk assessment tool that
addresses the questions of various
stakeholders
 Define the boundaries between the
various CSL’s and where those
boundaries blur
 Develop guidance documents for use of
CSL’s

�ݺ�ߣ

Stuart Csl Risk Assessment

More Related Content

Stuart Csl Risk Assessment