Wash. Rev. Code § 88.46.230
(1) When submitting a contingency plan to the department under RCW 88.46.060, any umbrella plan holder that enrolls both tank vessels and covered vessels that are not tank vessels must, in addition to satisfying the other requirements of this chapter, specify:
(3) The department must approve an umbrella plan holder that covers vessels having a worst case discharge volume that exceeds the maximum volume if:
[ 2011 c 122 s 7.]