Well technically the only accidental outbreak would be from the Birkin lab in Raccoon City which spanned through several games.
The Arklay Research Facility is by Marcus as well as the training facility and Ecliptic Express. The Sheena Island outbreak was on purpose by Goldman. Rockfort Island was from a special forces unit which contaminated to the Antarctica Research Facility. The Spencer Rain was also deliberate. The facility in Russia was also the result of sabotage. So yeah, only one really accidental was Raccoon City.