The term "employment" shall not include casual labor not in the course of the employer's trade or business (labor which does not promote or advance the trade or business of the employer). Temporary labor in the usual course of an employer's trade or business or domestic services as defined in RCW 50.04.160 shall not be deemed to be casual labor.

Effective dates—1977 ex.s. c 292: See note following RCW 50.04.116.