Document 5b6eM96ZY2VKJ3QKkQ51k20n0

DOCUMENTATION OF THRESHOLD LIMIT VALUES AMERICAN CONFERENCE OF GOVERNMENTAL INDUSTRIAL HYGIENISTS COMMITTEE ON THRESHOLD LIMIT VALUES Copies of this publication may be obtained from*. Secretary-Treasurer American Conference of Governmental Industrial Hygienists 1014 Broadway Cincinnati 2, Ohio Price per copy $4.00 Make checks payable to American Conference of Governmental Industrial Hygienists Copyright 1962 by American Conference of Governmental Industrial Hygienists li OLI 3810 PREFACE The documented evidence appearing in this publication has been taken mainly from technical papers and texts of industrial hygiene and toxicology that have appeared over the years and from the experience and knowledge of committee members. All informational sources are referenced. Occasionally, written communications to the committee members have been used to supplement formally published material, when such information has been substantiated by valid observation. It is this material that has been used in deriving the values given in the table of threshold limits which is published annually by the American Conference of Govern mental Industrial Hygienists. The format is designed to supply in brief the best available tech nical evidence substantiating the choice of the limiting concentrations. Substances are listed in alphabetical order for ready reference. The evidence on individual substances in this compilation is not necessarily final. The format facilitates the supplementation or modification of existing data, or the addition of information on new substances as it becomes available. The committee urges careful study and review of this publication and welcomes suggestions or new data that will maintain the usefulness of this publication. Supplements will be published and offered for sale as new information justifies their appearance. Communications should be addressed to the Chairman of the committee, Dr. H.E. Stokinger, or to the Secretary-Treasurer of the ACGIH. 1014 Broadway, Cincinnati 2, Ohio. ^commended limit of Roshchin. More recently Lewis (3) has reported no toxic mifestations from vanadium dusts, that included the pentoxide, among workmen exposed to concentrations of from 0.1-0.3 The lower limit of 0.1 mg/m3 for vanadium pentoxide fume is based on the recognizedly greater toxicity of fume, compared with dusts of larger size and smaller surface area. References 1. Roshchin, I.V.: Gig. i Sanit. 11, 49 (1953)* 2. Stokinger, H.E., Wagner, W.D., et al. To be published. 3. Lewis, C.E.: Arch. Ind. Health _19> 497 (1959)- VINYL CHLORIDE (CHLOROETHYLENE) 500 ppm (Approximately 1300 mg/m3) Patty and associates (1) found that guinea pigs inhaling 5000 ppm of vinyl chloride for several hours appeared to suffer no ill effects. Narcosis is the most important effect from inhaling this compound. The 500 ppm threshold limit appears to be sufficiently low to prevent sig nificant narcosis. Reference 1. Patty, F.A., Yant, W.F., White, C.P.: Pub. Health Rept. 45, 1963 (1930). VINYLTOLUENE 100 ppm (Approximately 480 mg/m^) This compound is a mixture of the meta and para isomers of methylstyrene. Rats, guinea pigs, rabbits, mice, and monkeys tolerated vapor concentrations of 600 ppm of vinyltoluene given repeated exposures 7 hours a day, 5 days a week for periods ranging from 4 to 5 months. The animals were normal as judg ed by growth, mortality, hematology, organ weight, gross and microscopic exami nation of the tissues, blood urea nitrogen values, and qualitative urine tests. Thus, vinyltoluene is similar in toxicologic properties to monomeric sty rene. Like styrene, concentrations of the order of 600 ppm are extremely dis agreeable to human subjects. The authors recommended a threshold limit value of 400 ppm based on toxicity, but suggest that atmospheric contamination be maintained at 100 ppm or less in order to avoid discomfort. Reference 1. Biochemical Dept., Dow Chem. Co., Midland, Mich., unpublished summary. WARFARIN (3-(C-acetonylbenzyl)-4, hydroxycourmarin) 0.5 mg/m3 This rodenticide is the prototype of the anticoagulants. Lehman (l) has Reported its acute oral toxicity as 160 mg/kg for rats. Its hazard is its ^plative effect and for this reason the threshold limit should be lower the acute LD^q would suggest. A threshold limit of 0.5 mg/m3 is recom mended. Reference OLI 3812 1. Lehman, A.J.: U.S. Food & Drug Adm. Quart. Rept., October 1951* 110 COMMITTEE ON of the * AMERICAN CONFERENCE OF GOVERNMENTAL INDUSTRIAL, HYGIENISTS 1968 NOTICE OF INTENT This Notice of Intent is published so that industry-connected individuals principally, but others also, may have an opportunity to help shajfe the deliberations of the Committee prior to its recommendations of tentative changes in the 1967 Threshold Limits List, This can be done by submitting to the Chairman comments on the intended changes, with supporting data, or by submitting new data on Substances not within the Notice of Intent. This Notice is not binding on the Committee to place all substances listed below In the 1968 Edition, nor does it restrict the Committee to these sub stances; substances with appropriate supporting data received following the publication of this list will be considered at the next Committee meet ing for inclusion in the 1968 Edition, This Notice indicates only those substances that are under consideration by the Committee. Documentation is available upon request for those substances bearing a threshold limit v alue , All comments should reach the Chairman by March 15, 1968. Address: Dr. Herbert E. Stoklnger, U.S. Public Health Service, 1014 Broadway, Cincinnati, Ohio 45202, If preferred, information may be sent to the Repository of Anonymous Occupational Health Data, % Dr. R.T. P. de Treville. Industrial Hygiene Foundation, 4400 Fifth Ave., Pittsburgh, Pa.15213 The following list of Proposed Revisions and Additions for the 1968 Threshold Limits List has resulted from the fall meeting of Plenary Conmittee REVISIONS UNDER CONSIDERATION SubstanceFrom 1967 ListProposed for 1968 List__ __ ^ppm, mg/ro-^ or mppcf ppm, mg/m^ or mppcf Asbestos* 5 Benzene Butyl mercaptan Cristobalite* Tridymite* 7. Ethyl mercaptan Heptane Methyl mercaptan Octane C25 10 250 mppcf Si0-+5 *10 200 / 10----- 200 *Appendix 7. A limit of 5 mppcf, based on lmpinger samples counted by light-field technics, is satisfactory to control exposures to most forms of as bestos. Crocidolite, however, has been shown to produce, in addition to the asbestotic inflammation, also mesofhe 1ioma. Since no safe limit can be established for this form of asbestos at this time, until more definitive data are obtained, it is recommended that workers exposed to crocidolite be equipped with air-supplied he lests. ,' 10 0.5 Downward revision by a factor of 2.5? OLI 3813 1968 Notice of Intent - Continued Substance From 1967 List ppm, mg/m3 or mppcf Proposed for 1968 List pfrm, mg7m^ or mppcf Oil Mists* 5 5* Collected by el ectrostatic precipitator. If va pors involved, apply appropriate pentane Petroleum distillates Quartz 1000 250 mppcf TLV 5g A^ 10 mg/m % Si02 +5 % Resp. free Si02*+2 (alternative mass form.) Respirable free Si02 as defined by Stoddard solvent Tetraethyl lead Tetramethyl lead 500 0.075 0.075 Are o dynamic Diane ter (Unit density sphere) micra < 2.0 2.5 3.5 5.0 10.0 200 Downward revision II II Minimal I Collected 90 75 50 25 0 1. ADDITIONS UNDER CONSIDERATION Substance Dichloroacetylene Endosulfan (thiodan) Indene Methyl isoamyl alcohol Pentaerythritol Rosin fumes skin Proposed Limit C 0.1 ppm 0.1 mg/m 10 ppm 100 ppm 15 mg/m 0.2 mg/m DESIRABLE SUBSTANCES FOR ADDITION, BUT FOR WHICH INADEQUATE DATA EXIST / Information pertinent to the recommendat ion of an industrial air limit is solicited on the following subs tance s: Aluminum * p owd e r Mercaptobenzothiazole Benzothiazyl disulfide (Poly) vinyl chloride Butyl lactate Silicon tetrachloride o-Chlorostyrene Silicon tetrafluoride Hexafluoroacetone Trimethyl benzene Hexafluorolsopropanol Vinyl acetate Dr. Herbert E. Stokinger, Chairman TLV Committee, ACGIH November 22, 1967 OLI 3814