It seems quite possible. Japan aside (and those largely weren’t “accidents”), the anthrax accidentally released at Sverdlovsk by the USSR program is a major one. I think Alibek describes more in his book Biohazard, but I’m not certain, and nothing else on the scale of that incident. It seems possible that there have been more accidental releases to civilian populations, than just these.
It seems quite possible. Japan aside (and those largely weren’t “accidents”), the anthrax accidentally released at Sverdlovsk by the USSR program is a major one. I think Alibek describes more in his book Biohazard, but I’m not certain, and nothing else on the scale of that incident. It seems possible that there have been more accidental releases to civilian populations, than just these.