Every employer, who employs workers, shall keep as required by the department's rules a first aid kit or kits equipped as required by such rules with materials for first aid to his or her injured workers. Every employer who employs fifty or more workers, shall keep one first aid station equipped as required by the department's rules with materials for first aid to his or her injured workers, and shall cooperate with the department in training one or more employees in first aid to the injured. The maintenance of such first aid kits and stations shall be deemed to be a part of any safety and health standards established under Title
49 RCW.