No, never in the history of humanity has there ever been anything spilled in the ocean.
"Minor" oil spills are usually not televised by the media nearly as much as oil spills that have a larger impact on the environment. So we'll never know for sure. However, there are at least thirty-six oil spills that have happened since 1967.
Source: InfoPlease.com 
Yes the Exxon Valdez was a environment bad oil spill where the mate was goofing off on the bridge.