Iranian authorities are reporting no signs of off-site radiation or contamination in the wake of U.S. attacks on three of the country’s nuclear sites. […] That’s according to a statement put out by the International Atomic Energy Agency on Sunday. Rafael Mariano Grossi, the agency’s Director General, said that “as of this time, we don’t expect that there will be any health consequences for people or the environment outside the targeted sites.”
I’ve read that the UN atomic energy commission has also said that they haven’t measured any increases in radiation, so it doesn’t look likely to me that Iran is hiding anything.
I also saw an article where they showed satellite images indicating that Iran may have evacuated a lot of materiel from Fordow shortly before the strikes.