TLV ® Chemical Substances Committee. The Process for Decision Making Presented at the AIHce June 3, 2002, San Diego, CA Bill Wells PhD, CIH, CSP, Moderator Dennis Casserly, PhD, CIH & Marilyn Hallock, CIH Monitors. Forum Overview. Scott Merkle: ACGIH ® Structure
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The Process for
Presented at the AIHce
June 3, 2002, San Diego, CA
Bill Wells PhD, CIH, CSP, Moderator
Dennis Casserly, PhD, CIH & Marilyn Hallock, CIH Monitors
Scott Merkle, CIH
National Institute of Environmental Health Sciences
Statement of Activities
Other House Pubs.
TLV®/BEI® Book & CD-Rom
Ind. Vent. Manual & CD-Rom
Statement of Activities
Committees provide the creativity, initiative, and technical expertise that has made ACGIH® what it is today and what it will be tomorrow.
The development and sharing of chemical toxicity data (pre- and post- OSHA & TSCA).
How to assess risks for carcinogenic effects.
The (Mis)use of TLVs® for non-occupational exposures.
1980s - Present
International “harmonization” of values, or of the underlying definitions and principles.
Marshalling the resources needed to support the development of voluntary guidelines.
Concerns that influences from corporate and governmental interests can contaminate the process.
1980s - Present
In December 2000, ACGIH® was named as a defendant in 3 separate lawsuits --
Development of regulatory options
Evaluation of social, economic & political
The process of organizing, evaluating, and communicating information about the nature, strength of evidence, and likelihood of adverse health effects from particular exposures.
Final Report: The Presidential/Congressional Commission on Risk Assessment and Risk Management, 1997
ACGIH is not a standards setting body.
TLVs® and BEIs®—
TLVs® and BEIs®—
Lisa Brosseau, ScD, CIH
University of Minnesota
Chair, TLV®-CS Committee
Board of Directors
Chair of TLV® Committee
(Membership, Chemical Selection)
Dust & Inorganics Subcommittee(D&I)
Hydrogen, Oxygen, Carbon Subcommittee (HOC)
Miscellaneous Compounds Subcommittee
Technical, economic, and analytic feasibility are NOT considered
Published / Peer Reviewed Science
Use uncertainty factors, if necessary (but no “rules”)
Look for threshold of effects
Consider irritation an important health endpoint
Not concerned with levels of risk
Look for the “worst case” health endpoint
Always select an exposure level
Explain the reasons for our recommendationsSummary
Patrick N. Breysse, PhD, CIH
Johns Hopkins University
Bloomberg School of Public Health
“Views stated or positions taken that are largely intellectually motivated or arise from close identification or association of an individual with a particular point of view or the positions or perspectives of a particular group.”
“Any financial or other interest which conflicts with the service of an individual because it: (1) could impair the individual’s objectivity, or (2) could create an unfair competitive advantage for any person or organization.”
Philip Bigelow, PhD, CIH
Florida A&M University
Institute of Public Health
Daniel J. Caldwell, Ph.D., CIH, DABT
ExxonMobil Biomedical Sciences, Inc.
Appendix C, TLVs® for Mixtures
Global interest: MAK, ACGIH®, IRSST
To develop a generic and harmonized method for setting exposure limits for hydrocarbon solvents.
Generic: • Include all hydrocarbon solvents
• Maximum advantage of existing data
• Minimize effects of minor differences
Harmonized: • Similar solvents have similar TLVs®
• Consistent health advice worldwide
Properties of Hydrocarbon Solvents:
KEY MESSAGE - Hydrocarbon solvents are a family of materials
which contain constituents with similar chemical properties.
Procedure To Set TLV® For Hydrocarbon Solvents:
Determine Sum Of Fractional TLVs® :
1 =Fractiona+Fractionb+ Fractionn
TLVmixture TlVa TLVb TLVn
KEY MESSAGE - RCP is based on ACGIH® mixtures formula
1 Assumes similarity of vapor and liquid compositions.
KEY MESSAGE - An RCP procedure can be used for complex
substances if they contain constituents with similar physical
and chemical properties
What do you do when you don’t have a TLV®?
KEY MESSAGE - If group values are developed, TLVs® can be
calculated for hydrocarbon solvent mixtures using a RCP.
C5-C8 Aliphatics/cycloaliphatics 1500 mg/m3
C9-C15 Aliphatics/cycloaliphatics 1200 mg/m3
C7-C8 Aromatics 200 mg/m3
C9-C15 Aromatics 100 mg/m3
Others: n-hexane 175 mg/m3
Naphthalene 50 mg/m3
Cyclohexane 350 mg/m3
Generic Term Applied To Hydrocarbon Fractions:
KEY MESSAGE - Mineral spirits is a generic term for a range of hydrocarbon solvents..
Boiling range 150-200°C
Flash Point ~38°C
Carbon number range 8-12
Average molecular weight 141
%w/w n-/iso-cyclo-Alkanes (C5-C8) 7.4
% w/w n-iso-cyclo-Alkanes (C9-C15) 76.5
% w/w Aromatics 16.1
comprising C7/C8 aromatics 2.0
C9 aromatics 8.3
Non-listed aromatics 5.8
Using the proposed guidance values for mineral spirits and substituting these values in the RCP formula:
__1__ = __Fra_+ ___Frb__+ ..... _Frn__
TLV sol TLVa TLVb TLVn
= 0.074 + 0.765 + 0.020 + 0.141 1500 1200 200 100
= 0.000049 + 0.00064 + 0.0001 + 0.00141
The RCP approach is:
Group Guidance Values can be used to calculate TLVs® because:
Sources of Data
Mechanism of Sensory Irritation - HumanChemosensory System
Perception of Irritation Impacted By
Current Research Areas
Appendix E: Particulates (insoluble or poorly soluble) Not Otherwise Specified
Airborne concentrations should be kept:
until such time as a TLV® is set.
OTHER REPRESENTATIVE HYDROCARBON SUBSTANCES