double hulls
... that after the 1989 Exxon Valdez oil spill, all new oil tankers built for use between U.S. ports were required to have full double hulls?
... that after the 1989 <a href="./Exxon_Valdez_oil_spill" id="mwAS4" rel="mw:WikiLink" title="Exxon Valdez oil spill"><i id="mwAS8">Exxon Valdez</i> oil spill</a>, all new oil tankers built for use between U.S. ports were required to have full <b id="mwATA"><a href="./Double-hulled_tanker" id="mwATE" rel="mw:WikiLink" title="Double-hulled tanker">double hulls</a></b>?