Document qazpnMyOjvZkp3YpQ5983qwEq

1 appear that most of the plant contamination is Page 1570 2 resulting from this source. 3 Therefore, before a precise determination 4 can be made regarding dust levels generated by 5 specific deflashing and mixing operations, improved 6 engineering control must be installed in the 7 collectors. 8 As in our previous study in 1967, we 9 recommend that the air from the collectors be 10 discharged directly to the outside of the building. 11 Referring to the Michigan Department of 12 Public Health, Division of Occupational Health 13 administrative code for occupational air contaminants 14 and physical agents establishes specific rules with 15 regard to the recirculation of the contaminated air 16 from dust collectors. 17 The code has this requirement in paragraphs 18 2 and 3. The director may allow the recirculation of 19 air containing a contaminant whose MAC is less than 20 1,000 parts per million, 15 milligrams per cubic meter 21 or 50 million particles per cubic foot if the toxicity