(a) Total fluorides, parts per million (ppm), dry weight basis (as F) in and on forage for consumption by grazing ruminants. Average concentration shall be less than the following in all levels:

1. (1) For growing season (not to exceed six consectuive months) — 40 ppm
2. (2) For any 60 day period — 60 ppm
3. (3) For any 30 day period — 80 ppm

(b) Gaseous fluorides in air (parts per million parts of air) as F—all levels. (25 degrees Centigrade, 760 min. Hg.)

1. (1) 12 hour averages to be less than 4.5 ppb (3.7 μg/m³)
2. (2) 24 hour averages to be less than 3.5 ppb (2.85 μg/m³)
3. (3) 1 week averages to be less than 2.0 ppb (1.65 μg/m³)
4. (4) 1 month averages to be less than 1.0 ppb (0.8 μg/m³)