On April 20th in 2010, an oil drilling rig had exploded and blazed up in Gulf of Mexico. Two days later, the rig had sunk in sea, the oil leak from the damaged well had continued 87 days. The outflow of crude oil by this accident was maximum level in history and had a special feature of oil spill comparing to the one from the ships such as oil tankers.
　PARI dispatched research team to the United States from 11th to 18th of July 2010 to investigate the impact of the oil spill. This report is based on PARI’s field observation as well as other materials, and provides the overview of the incident including how the incident happened, how the oil drifted and damaged the coast line, as well as how the clean-up operation was carried out.