(1) "Potentially dangerous dog" means any dog that when unprovoked: (a) Inflicts bites on a human or a domestic animal either on public or private property, or (b) chases or approaches a person upon the streets, sidewalks, or any public grounds in a menacing fashion or apparent attitude of attack, or any dog with a known propensity, tendency, or disposition to attack unprovoked, to cause injury, or to cause injury or otherwise to threaten the safety of humans or domestic animals.

(2) "Dangerous dog" means any dog that (a) inflicts severe injury on a human being without provocation on public or private property, (b) kills a domestic animal without provocation while the dog is off the owner's property, or (c) has been previously found to be potentially dangerous because of injury inflicted on a human, the owner having received notice of such and the dog again aggressively bites, attacks, or endangers the safety of humans.

(4) "Proper enclosure of a dangerous dog" means, while on the owner's property, a dangerous dog shall be securely confined indoors or in a securely enclosed and locked pen or structure, suitable to prevent the entry of young children and designed to prevent the animal from escaping. Such pen or structure shall have secure sides and a secure top, and shall also provide protection from the elements for the dog.

(5) "Animal control authority" means an entity acting alone or in concert with other local governmental units for enforcement of the animal control laws of the city, county, and state and the shelter and welfare of animals. In the absence of an animal control authority, local law enforcement is the animal control authority.

(6) "Animal control officer" means any individual employed, contracted with, or appointed by the animal control authority for the purpose of aiding in the enforcement of this chapter or any other law or ordinance relating to the licensure of animals, control of animals, or seizure and impoundment of animals, and includes any state or local law enforcement officer or other employee whose duties in whole or in part include assignments that involve the seizure and impoundment of any animal.

(1) Any dangerous dog shall be immediately confiscated by an animal control authority if the: (a) Dog is not validly registered under RCW 16.08.080; (b) owner does not secure the liability insurance coverage required under RCW 16.08.080; (c) dog is not maintained in the proper enclosure; or (d) dog is outside of the dwelling of the owner, or outside of the proper enclosure and not under physical restraint of the responsible person. The owner must pay the costs of confinement and control. The animal control authority must serve notice upon the dog owner in person or by regular and certified mail, return receipt requested, specifying the reason for the confiscation of the dangerous dog, that the owner is responsible for payment of the costs of confinement and control, and that the dog will be destroyed in an expeditious and humane manner if the deficiencies for which the dog was confiscated are not corrected within ((twenty))20 days. The animal control authority shall destroy the confiscated dangerous dog in an expeditious and humane manner if any deficiencies required by this subsection are not corrected within twenty days of notification. In addition, the owner shall be guilty of a gross misdemeanor punishable in accordance with RCW 9A.20.021.

(2) If a dangerous dog of an owner with a prior conviction under this chapter attacks or bites a person or another domestic animal, the dog's owner is guilty of a class C felony, punishable in accordance with RCW 9A.20.021. It is an affirmative defense that the defendant must prove by a preponderance of the evidence that he or she was in compliance with the requirements for ownership of a dangerous dog pursuant to this chapter and the person or domestic animal attacked or bitten by the defendant's dog trespassed on the defendant's real or personal property or provoked the defendant's dog without justification or excuse. In addition, the dangerous dog shall be immediately confiscated by an animal control authority, placed in quarantine for the proper length of time, and thereafter destroyed in an expeditious and humane manner.

(3) The owner of any dog that aggressively attacks and causes severe injury or death of any human, whether or not the dog has previously been declared potentially dangerous or dangerous, shall, upon conviction, be guilty of a class C felony punishable in accordance with RCW 9A.20.021. It is an affirmative defense that the defendant must prove by a preponderance of the evidence that the human severely injured or killed by the defendant's dog: (a) Trespassed on the defendant's real or personal property which was enclosed by fencing suitable to prevent the entry of young children and designed to prevent the dog from escaping and marked with clearly visible signs warning people, including children, not to trespass and to beware of dog; or (b) provoked the defendant's dog without justification or excuse on the defendant's real or personal property which was enclosed by fencing suitable to prevent the entry of young children and designed to prevent the dog from escaping and marked with clearly visible signs warning people, including children, not to trespass and to beware of dog. In such a prosecution, the state has the burden of showing that the owner of the dog either knew or should have known that the dog was potentially dangerous as defined in this chapter. The state may not meet its burden of proof that the owner should have known the dog was potentially dangerous solely by showing the dog to be a particular breed or breeds. In addition, the dog shall be immediately confiscated by an animal control authority, quarantined, and upon conviction of the owner destroyed in an expeditious and humane manner.