It is an extremely radioactive synthetic element that can only be created in a laboratory.

Most synthetic radioisotopes are extremely radioactive and have a short half-life.

The stone could transmute the elements all right, but the changing atomic weight meant you ended up with extremely radioactive gold.

It is both extremely radioactive and toxic.

The spent fuel rods were extremely radioactive, and the process for recovering the plutonium used only remote-controlled equipment.

It is an extremely radioactive synthetic element.

Californium-252 is a very strong neutron emitter, which makes it extremely radioactive and harmful.

It's extremely radioactive, and I'd hate to see pieces of it end up as part of somebody's sleeping quarters.

Its side facing the bomb was extremely radioactive but there was virtually no danger inside the vessel.

Amazingly, I discover that my hull is extremely radioactive, the result of an intense neutron bombardment.