The NYT has deemed the plant "damaged" after an extremely small spill and an extremely small leak ... without specifying the sources or the amounts.
I thought I read that the source of the spill was a container of low level waste, not from the operating equipment itself. Its entirely possible that the exhaust filter contains airborn particles from the spilled container.
Since this plant was a BWR, this low level waste was likely some resins used in cleaning up the reactor water. “Low level” is a reletive term, and waste resins usually have very high dose rates (I’ve measured 50 R/Hr outside the casks).