Understand, I am not arguing that it is sensible.
It was safe to take Ivermectin for COVID all the time, but the Government and the media kept it from the public, just as the Deep State kept the truth about JFK's assassination and the truth about 9-11 from the public. The state will say it was Russia, Russia, Russia and many, perhaps most, will believe it, just as many still believe that US attacking Iraq was correct after 9-11.
This is just my opinion of the way that the Deep State has acted, can act and will act in the future. It doesn't have to be completely rational when they can censor and manipulate the truth.

the "material" can be gathered down-wind

Oh, I wouldn't be surprised one bit.

As arrogant as they are about control of the narrative, I doubt they'd be concerned about the source of the material.
"It's too dangerous for any civilians to go there. We have 'top men' investigating." ;^) (credit to Raiders of the Lost Ark.)

i'd not be surprised one bit
issue it the source of the material can be tracked

but we have Soviet material from K-129 and the CIA's recovery of the sub.
yes, we recovered the whole sub or else we would not have been able to give back the sub's bell to the Soviets, we put back part of it to cover what we kept.

we likely also have Soviet nuclear material from other sunk Soviet subs, like the Yankee Missile Sub lost off of the United States