Document MMrp6NE1jqvMKm3mMRqB0JBky

f A "no visible emission" standard has been added to the trans portation regulation. The emission standard would measure only fibers longer than five microns. The justification for this seems to be the adminis trative convenience of avoiding difficulties in measuring fibers from .5 to five microns in length. Some medical evidence has in dicated that the very small fibers may be the most dangerous. The Board will continue to examine the medical implications of the subfive micron fibers and the means of measurement and control. Part V, Sec. SOI (a) - has been slightly changed from the pro posed final draft to add the phrase "into the ambient air" in order to make clear that the emission standard does not apply to the inplant atmosphere. In Part V; See. -502 - the'word "enclose" has been-changed to "control" on the suggestion that as previously written the meaning was unclear and implied total enclosure of all facilities. Our original proposal would have prohibited the use of brake lining in vehicles manufactured after January 1, 1975 and sold for use in Illinois. It was believed if brake lining decomposition emits asbestos fiber, then the tremendous number of vehicles using asbestos, and the impracticability bf controlling these numerous small emission sources would appear to speak to the need for a pro duct ban. This proposal to ban asbestos brake lining has been dropped for the time being. While the evidence shows that brake lining decomposi tion is a significant source of background levels of asbestos, these ambient air levels are quite small and have not been shown to be a health hazard (although they have npt been shown not to be). In addition, adequate alternatives to asbestos-lined brakes are not yet available, although closed braking systems, preventing the emission of asbestos dust,are possible. The Board will follow the medical and engineering aspects of this problem and possibly may return to it. Finally, local governments are obliged to enforce these regula tions, except for the manufacturing provisions. Much of the problem arises from numerous construction activities, and the Agency-cannot adequately supervise these many emission sources. The "no visible emission" standard has been added especially to facilitate local government and citizen assistance in enforcement. I, Christan Moffett, Clerk of the Illinois Pollution Control Board, certify that the above Opinion was adopted on the day of 19 72 by a vote Of 4-0. 3 -- 459