(1) The following activities are exempt from the license and permit requirements of the act and these rules:

(a) state and federal agencies, colleges, and bona fide non-profit research organizations;

(b) laboratory research and experiments;

(c) activities for protection against an imminent threat to life or property caused by fire, frost, sleet, or fog; and

(d) activities normally engaged in for purposes other than those of inducing, decreasing, or preventing precipitation or hail.