Twenty years ago, the oil tanker Exxon Valdez was exiting Alaska’s Prince William Sound when it struck a reef in the middle of the night. What happened next is considered one of the nation’s worst environmental disasters: 10.8 million gallons of crude oil spilled into the pristine Alaskan waters, eventually covering 11,000 square miles of ocean. Now, imagine 8 to 80 times the amount of oil spilled in the Exxon Valdez accident. According to new research, that’s how much oil has made its way into sediments offshore from petroleum seeps near Coal Oil Point in the Santa Barbara Channel.