MODOC COUNTY AIR POLLUTION CONTROL DISTRICT

RULE 4.1 - VISIBLE EMISSIONS
(Amended January 15. 1989)

Except as provided in these regulations, 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 one hour which is:

1. As dark or darker in shade as that designated as No. 2 on the Ringelmann 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. of this rule.
3. The provisions of Rule 4.1.A. and Rule 4.1.B. shall not apply to:
   1. Fires set pursuant to Rule 4.3.
   2. Agricultural burning for which a permit has been granted pursuant to Regulation VII.
   3. Use of any aircraft to distribute seed, fertilizer, insecticide, or other agricultural aids overlands devoted to the growing of crops or raising of fowl or animals.
   4. The use of orchard and citrus grove heaters which are in compliance with the requirements set forth in Rule 4.11.
   5. Fires set or permitted by any public officer in the performance of his/her official duty for the improvement of watershed, range, or pasture.
   6. Agricultural operations necessary for the growing of crops or raising of fowl or animals.
   7. The use of other equipment in agricultural operations necessary for the growing of crops or raising of fowl or animals.
   8. The use of visible emission generating equipment in training sessions conducted by governmental agencies necessary for certifying persons to evaluate visible emissions.
   9. Smoke emissions from teepee burners operating in compliance with Section 4438 of the Public Resources Code during the disposal of forestry and agricultural residues or forestry and agricultural residues with supplementary fossil fuels when such emissions result from the startup or shutdown of the combustion process or from the malfunction of emission control equipment. This exception shall not apply to emissions which exceed a period or periods of time aggregating more than 30 minutes in any 24-hour period. This exception shall not apply to emissions which result from the fai1ure to operate and maintain in good working order any emission control equipment.
   10. Smoke emissions from burners used to produce energy and fired by forestry and agricultural residues with supplementary fossil fuels when such emissions result from startup or shutdown of the combustion process or from the malfunction of emission control equipment. This exception shall not apply to emissions which exceed a period or periods of time aggregating more than 30 minutes in any 24-hour period, or which result from the failure to operate and maintain in good working order any emission control equipment.
   11. Emissions from methanol fuel manufacturing plants which manufacture not more than 2,000,000 gallons of methanol fuel per day from wood agricultural waste, natural gas, or coke (exclusive of petroleum coke). As used in this rule, "manufacturing plant" shall include all necessary support systems, including field operations equipment that provide feed stock. However, this exception shall apply to not more than one such methanol fuel manufacturing plant in the Northeast Plateau Air Basin and each such plant shall be located in an area designated as an "attainment area" pursuant to the Clean Air Act (42 U.S.C. 7401 et seq.) and shall meet all applicable standards required by the district board. This exception shall remain in effect with respect to such a plant until five years after construction of the plant and shall have no force and effect with respect to such a plant on and after such date.
4. When the presence of uncombined water is the only reason for the failure of an emission to meet the visible emissions limitation (Rule 4.1), that 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.