I don't know that much about razor clams, even in WA. It took some internet digging, but there are records (see
here, table 1) of the similar jackknife clam (
Ensis lees or
E.
americanus (invalid name) in Washington where it must be invasive. The jackknife clam has become an invasive pest in Europe. In some states, like Massachusetts, it is legal to use a salt solution to drive the clams to the surface (see
here) for harvest. I do remember from growing up in the Boston area that we were warned about handling these because the sharp edges of the shell could cut a hand or fingers run along the edge of the shell.
Steve