Why is scuba diving permitted at Bikini Atoll even though permanent settlement is not allowed?

Scuba diving is permitted at Bikini Atoll because, while the atoll remains contaminated with radiation from historical nuclear testing, the radiation levels are considered low enough to allow for tourism, even though they remain too high to support safe, permanent human settlement.12

Following extensive nuclear testing by the United States between 1946 and 1958, the land and its resources were rendered unsafe for habitation, as nothing grown on the contaminated soil is safe to eat. However, the atoll was opened for scuba diving in 1996, allowing visitors to explore the unique site of the lagoon’s sunken warships, which were used as targets during the atomic experiments.12