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ACGIH ® TLVs ® for Chemical Substances Committee Update. Chair: Lisa M. Brosseau, ScD, CIH Associate Professor University of Minnesota School of Public Health. Overview.
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ACGIH® TLVs® for Chemical Substances Committee Update Chair: Lisa M. Brosseau, ScD, CIH Associate Professor University of Minnesota School of Public Health
Overview • TLV®-CS Committee has 20 members and 3 member-candidates, who volunteer time towards developing scientific guidelines and publications • Primary goal is to serve the scientific needs of industrial hygienists • Committee expenses (travel) are supported by ACGIH® • Time is donated by the members
Committee Structure • Chair and Vice Chair • Three Subcommittees, Chair and Co-Chair • Dusts & Inorganics (D&I) • Hydrogen, Oxygen & Carbon Compounds (HOC) • Miscellaneous Compounds (MISCO) • Administrative Subcommittees • Communications and Outreach • Membership • Notations • Chemical Substance Selection • Staff Support • Liaison, Clerical, Literature Searching
Chemical Substance Subcommittees • Approximately 10 members on each • Membership from academia, government, unions, industry • Membership represents four key disciplines: • Industrial hygiene • Toxicology • Occupational Medicine • Occupational Epidemiology
Core TLV® Principles • Focus on airborne exposures in occupational settings • Utilize the “threshold” concept • Primary users are industrial hygienists • Goal is towards protection of “nearly all” workers Technical, economic, and analytic feasibility are NOT considered
Committee Actions in 2003 • Adopted TLVs® for 22 substances • Proposed 6 new TLVs® • (listed on the Notice of Intended Changes (NIC)) • Revised 7 adopted TLVs® (listed on the NIC) • Proposed withdrawing TLVs® for methane, ethane, propane, butane and liquified petroleum gas. (Will also withdraw iso-butane.) • All to be replaced with a proposal for Aliphatic Hydrocarbon Gases, Alkane (C1-C4) • Revised 3 proposals for TLVs® and retained on the NIC
Committee Actions in 2003 (Cont’d) • Adopted a new Appendix E for Particulates (Insoluble or Poorly Soluble) Not Otherwise Specified (PNOS) • Developed new Documentation for 2 substances (no change in values) • Changed the name of one TLV® and kept on the NIC with revised recommendations • Retained 4 proposed TLVs® on the NIC • Withdrew 2 proposed TLVs® from the NIC
Committee Actions in 2003 (Cont’d) • Proposed withdrawal of Appendix B: Substances of Variable Composition • Proposed revision of Appendix C: Threshold Limit Values for Mixtures • Proposed a new Appendix F: Commercially Important Tree Species Identified as Inducing Sensitization
Substances and Issues Under Study in 2003 • 115 chemical substances currently under study • Issues under study include: • Ceiling limits, excursions, and STELs • Notations for reproductive effects • Skin notation • Reciprocal Calculation Procedure, Group Guidance Values for refined C5 - C15 aliphatic and aromatic hydrocarbon solvents and constituent chemicals
Particulates(Insoluble or Poorly Soluble) Not Otherwise Specified • The recommendations are guidelines (not TLVs®) for limiting exposure to insoluble particles: • 3 mg/m3 (respirable) • 10 mg/m3 (inhalable) • Apply to particles that: • Do not have a TLV® • Are insoluble or poorly soluble in water or lung fluid • Have low toxicity (not genotoxic, cytotoxic, etc.) • Only toxic effects are inflammation or “lung overload” mechanisms
ProposedNew Appendix C: TLVs® for Mixtures • In the absence of other information, assume additivity of substances having similar effects • Same outcomes, same target organs or systems the TLV® for the mixture has been exceeded.
ProposedNew Appendix C: TLVs® for Mixtures • Recommends using the TLV®Documentation, as well as the TLV® Basis information in the book • Where possible, only combine TLVs® having a similar time basis • Table showing appropriate combinations of different types of TLVs®
ProposedNew Appendix C: TLVs® for Mixtures • Limitations and Special Cases • Do not use when suspect inhibition or synergism • Take care when considering mixtures of A1, A2, or A3 carcinogens • Not appropriate for complex mixtures with many different components (e.g., gasoline, diesel exhaust)
Committee Activities • Notations • Complete re-write of Introduction to the TLV®-CS section of the book • Improved definition and categorization of TLV® Basis • Communications • Symposia on substances under study • Membership • Recruitment, especially of physicians and epidemiologists • Bill Wagner Award & member recognition • Chemical Substance Selection • Refining the selection process
Committee Activities • Sponsored symposium on TDI (Spring 2002) • Attended ACGIH® symposium on oil mists and metalworking fluids (Fall 2002) • Plenary talk on TLVs® at AIOH in Australia (Winter 2002) • Co-sponsored a colloquium on Workplace Chemical Exposure Standards with IRSST in Montreal (Spring 2003)
Committee Plans • Co-sponsor symposium on enzymes (Spring 2004) • Roundtables on TLVs® at other professional meetings (SOT, ACOEM) • Joint meetings with ACGIH® BEI® and AIHA WEEL Committees
Scheduled Break Take a minute to stretch!