 Ramba uchiverenga ndima ino - Muna 2007 mushumo weUnited States Environmental Protection Agency pamusoro pekudonha wakawedzera kukura kunofungidzirwa kwenzvimbo yakasvibiswa uye huwandu hunofungidzirwa hwekudonha kusvika, zvakapetwa katatu kudarika Exxon Valdez kudonha. Mushumo wacho wakatsoropodzawo nhamburiko dzokudzorera uye kunonoka kuchangobva kuitika kwokuchenesa. 