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 (C 1 -C 4 ) 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 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 C 5 - C 15 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/m 3 (respirable) –10 mg/m 3 (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

Proposed New 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.

Proposed New 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 ®

Proposed New 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

Questions?

Scheduled Break Take a minute to stretch!