As much as 300 millirem for some folks.
Quoth the NRC, getting a chest CT scan will expose you to 700 millirem. And then, on their "calculator" page, I found this gem:
18: Live within 50 miles of a nuclear power plant (pressurized water reactor) (0.0009 mrem)That's per year, by the way.
19: Live within 50 miles of a coal-fired electrical utility plant (0.03 mrem)
Oh, for those of you who will retort, "Live within 50 miles of Three Mile Island", STFU; adults are talking. Ditto for invoking Chernobyl, since that type of reactor has never been legal in the US for commercial power production.
IF you sat on top of the bucket for an hour, you would receive 280 millirem worth of radiation in that time frame. Half as much as you get from a single CT scan of your chest, and I don't see anyone panicking about that.
Otherwise? They don't list radioactive exposure for distances from the bucket, only from the outside of it. And these buckets weren't stored out in the open, either. Exposure would be attenuated by things like drywall and paint and simple distance from the source.
Probably a bad idea to camp out in the room they were in; but people walking past the wall behind which they were stored might get as much exposure as they got from their last dental x-rays.
This is nothing but scaremongering.