A carcass must be disposed of within seventy-two hours of the time of death or discovery to avoid nuisance odors or disease. If weather conditions prevent burial within seventy-two hours and rendering, composting, landfilling, or natural decomposition cannot be accomplished, then the carcass must be buried as soon as the weather permits. The following are acceptable methods for the routine disposal of carcasses:

(1) Burial.

(a) A carcass may be disposed of by burial on the property where the livestock animal died if done with the approval of the property owner.

(b) A carcass must be buried to a depth so that no part of the carcass is nearer than three feet to the natural surface of the ground. Every part of the carcass must be covered with at least three feet of soil within twenty-four hours of placement in the ground.

(c) Carcass burial must be:

(i) At least three hundred feet from any well, spring, or body of surface water, such as a river, stream, lake, pond, or intermittent stream;

(ii) At least three hundred feet from any residence not owned by the owner of the livestock animal;

(iii) At least fifty feet from any property line between parcels under different ownership; and

(iv) Not in a low-lying area subject to seasonal flooding or within a hundred-year flood plain or in a manner that will impact groundwater.

(d) Each burial site is limited to one thousand pounds of carcasses or one livestock animal weighing more than one thousand pounds.

(e) Carcass burial is not allowed on a property of less than five acres, except for the burial of a single carcass weighing less than two hundred pounds. The maximum amount of land used for burial during any year is limited to ten percent of the property or one acre, whichever is greater.

(2) Burning. Open burning of carcasses is not allowed for routine disposal under RCW 70.94.775.

(3) Composting. Composting must be conducted in compliance with chapter 70.95 RCW and chapter 173-350 WAC.

(4) Incineration.

(a) Complete incineration of carcasses to a mineral residue must be performed in an approved incineration facility or by a mobile air curtain incinerator; and

(b) Appropriate permits must be obtained in advance through the local air pollution control authority or the department of ecology in accordance with requirements of chapter 70.94 RCW, Washington Clean Air Act.

(5) Landfill. Carcasses may be disposed of at a privately or publicly owned landfill with prior approval of the local health officer and the landfill operator, and permitted in accordance with chapter 70.95 RCW and chapters 173-350 and 173-351 WAC.

(6) Natural decomposition. A livestock animal that dies on private or state rangeland from causes other than a significant infectious or contagious disease agent may be left to decompose naturally on that property as long as the carcass:

(a) Is at least one thousand three hundred twenty feet from any well, spring, sinkhole, or body of surface water such as a river, stream, lake, pond, or intermittent stream;

(b) Is at least one thousand three hundred twenty feet from any residence not owned by the owner of the dead livestock animal;

(c) Is at least one thousand three hundred twenty feet from any public roadway;

(d) Is out of public view; and

(e) Is left to decompose on the land with the property owner's permission.

(7) Digestion. Digestion of carcasses may be accomplished only in a properly designed and sized carcass digester approved by the director.

(8) Rendering. Carcasses may be rendered only by a rendering plant licensed under chapter 16.68 RCW, Disposal of dead animals.