Leave your answers in the comment box then move on to the next question
Before my time.
would guess 0.2 or 0.25mg/m3 in the 80’s??
thankful OES doesn’t relate to the amount of sand I probably ingested during the 80’s
In the 1980’s there was no national Australian exposure standard for respirable quartz or indeed any other substance, there was however a list of substances with recommended exposure standards produced by the Occupational Health Committee of the NHMRC and it was up to the State regulators to adopt these if they so desired. This often resulted in differences in approaches and values between states and also jurisdiction within states eg mining, construction or manufacturing.
In the early months of 1980 the NHMRC recommendation was
Siliceous dust; = 25 mg/m3 / (% respirable free silica + 5), it was then changed after considerable debate a few months later to;
Quartz-bearing dust = 0.2 mg/m3 respirable quartz providing that the concentration
of respirable dust does not exceed 5 mg/m3, with an explanation provided in 1983 that “A TLV of 0.2 mg/m3 is believed to be appropriate for quartz, having in mind the data on silicosis and exposure of sandstone workers in Sydney.”
In 1985 responsibility for setting national occupational exposure standards was transferred to the tripartite National Occupational Health and Safety Commission (NOHSC). In 1986 NOHSC republished the 1984 exposure standard list as guidance but refused to officially endorse the value (the reality was that most State occupational health legislation called up the NHMRC values and as such the historical values could not be readily rescinded). In 1990 and again in 1995, NOHSC issued a list of exposure standards but omitted an exposure value for respirable crystalline silica indicating that such was under review by an Expert Working Party. The Expert Working Party reported in 1993, however due to requirement for changes to made only after resolution by a three tiered tripartite industrial relations type bargaining system, NOHSC was unable to resolve the issue of a revised standard. So as to allow various state based OH&S regulations on silica to be enacted, in April 1996, NOHSC reissued the previous NHMRC exposure standard of 0.2 mg/m3. After a further two years of tripartite committee deliberations and public meetings NOHSC agreed at the end of 2004 on a revised exposure standard of 0.1 mg/m3 for crystalline silica (with the same value for cristobalite and tridymite) on the basis that the change would reduce the potential incidence of silicosis (even though there was conclusive evidence from various industries that implementation of the 0.2 mg/m3 standard had essentially eliminated silicosis in those industries).
At ridiculous levels
Your email address will not be published.
Forgot your password?
Lost your password? Please enter your email address. You will receive mail with link to set new password.
Back to login