(Adopted 8/2/76)

A. A person shall not discharge into the atmosphere from any single source of emission whatsoever any air contaminant for a period or periods aggregating more than three minutes in any hour which is:

  1. As dark or darker in shade as that designated as No. 2 on the Ringlemann Chart, as published by the United States Bureau of Mines.
  2. Of such opacity as to obscure an observer's view to a degree equal to or greater than does smoke described in Subsection A.1 of this Rule.


Each of the following is a separate exception to the Subsections A.1 and A.2 of this Rule:

  1. Wet or Dry Plumes. Where the presence of uncombined water is the only reason for the failure of an emission to meet the limitations of this Rule 401, said Rule shall not apply. The burden of proof which establishes the application of this exception shall be upon the person seeking to come within its provisions.
  2. Smoke from fires set by or permitted by any public officer if such a fire is set or permission given in the performance of the official duty of such officer, and such fire in the opinion of such officer is necessary:

    a. for the purpose of the prevention of a fire hazard which cannot be abated by any other reasonable means; or

    b. the instruction of public employees in the methods of fighting fire;

    c. for the improvement of watershed, range or pasture.

  3. Smoke from fires set pursuant to permit on property used for industrial purposes for the purpose of instruction of employees in methods of fighting fire.
  4. Agricultural operations in the growing of crops, or raising of fowls or animals.
  5. Orchard and citrus heaters meeting the requirements provided for by Section 41860 of the Health and Safety Code except that this exemption shall not apply to the provisions of Rule 402.
  6. The use of other equipment in agricultural operations in the growing of crops, or raising of fowls or animals.
  7. Smoke from fires set pursuant to Rule 501 pertaining to backyard burning.
  8. Smoke from burning for right of way clearing.
  9. Use of any aircraft to distribute seed, fertilizer, insecticides, or other agricultural aids over land devoted to the growing of crops and raising of fowls or animals.