Toxicology of Industrial Compounds

Figure 7.2 Continued
where RCF products are manufactured show that exposures are generally
below 1.0 f cm −3 , typically below 0.2 f cm −3 . In a recent study, RCF levels
during various end-user operations ranged from 0.12 to 1.55 f cm −3 with
an overall mean and SD of 0.74±0.49 f cm −3 (Lees et al., 1993b). Other
end-user studies have indicated that RCF exposures can exceed 5 f cm −3 or
higher if appropriate engineering controls and work practices are not
followed (Schuller, 1985–1988).
Fiber glass
T.W.HESTERBERG ET AL. 107
Recently, studies which examined human aerosol exposure to fiber glass in
manufacturing, installation and removal, and in ambient air were reviewed
(Hesterberg and Hart, 1994). In most cases, human exposures to airborne
fiber glass during manufacturing and installation fell well below the OSHAproposed
permissible exposure limit (PEL) of 1 f cm −3 air (OSHA, 1992).
Airborne fiber concentrations during FG manufacturing operations are
typically less than 0.2 f cm −3 , with the majority being less than 0.1 f cm −3 .
Exceptions include manufacture of finer diameter fiber glass and blowing
installation of loose fiber glass that is either milled or lacks binder. Airborne
levels averaging greater than 1 f cm −3 have been reported in the production
of finer diameter fiber glass (TIMA, 1990), while blowing installation of
loose fiber glass without binder resulted in a task length average (TLA) of
7.67 f cm −3 , and an 8-h TWA of 1.96 f cm −3 (Lees et al., 1993a). Blowing
installation of loose mineral wool also resulted in higher aerosol levels; a