RCW 70.77.495

It is unlawful for any person to set off fireworks of any kind in forest, fallows, grass, or brush covered land, either on his or her own land or the property of another, between April 15th and December 1st of any year, unless it is done under a written permit from the Washington state department of natural resources or its duly authorized agent, and in strict accordance with the terms of the permit and any other applicable law.