Mich. Admin. Code R. 325.2419
Current through Vol. 24-22, December 15, 2024
Rule 19. Table 7 reads as follows:
Table 7
Mineral Dusts
| Substance | MAC (mppcf) |
| Silica | |
| Crystalline * Quartz | MAC = 250/ % Si02 + 5 |
| Cristobalite | MAC same as quartz |
| Amorphous, including natural diatomaceous earth | 20 |
| Silicates (less than 1% crystalline silica) Asbestos, all types (see asbestos in construction R 325.51301 et seq.) | |
| Mica | 20 |
| Portland cement | 50 |
| Soapstone | 20 |
| Talc (non-asbestiform) | 20 |
| Talc (fibrous) (see asbestos in construction R 325.51301 et seq.) | |
| Tremolite (see asbestos in construction R 325.51301 et seq.) | |
| Graphite (natural) | 15 |
| Inert or nuisance particles ** | 50 of total dust less than 1% Si02 (or 15 mg/m3, whichever is the smaller) |
* The percentage of crystalline silica, Si02, in the formula is the amount determined from airborne samples.
* * The following are some examples of inert or nuisance particulates when toxic impurities are not present; e.g. quartz less than 1%.
| Alundum (A1203) | Gypsum | Rouge |
| Calcium carbonate | Limestone | Silicon carbide |
| Cellulose | Magnesite | Starch |
| Corundum (A1203) | Marble | Sucrose |
| Emery | Pentaerythritol | Tin oxide |
| Glycerine mist | Plaster of Paris | Titanium dioxide |
| Graphite (synthetic) | Portland cement | Vegetable oil mists (except castor, cashew nut, or similar irritant oils) |
Mich. Admin. Code R. 325.2419