Worst marine pollution
Who
Japan
What
20000 people
Where
Japan (Minamata Bay)
When
1953

A fertilizer factory on Minamata Bay, Kyushu, Japan, deposited mercury waste into the sea between 1953 and 1967. Up to 20,000 people were affected, 4,500 seriously. 43 people died from the poisoning; another 800 deaths were attributed to mercury poisoning by some sources, while 111 others suffered permanent damage.