Thus while the fission bombs
that destroyed Hiroshima, or the type that India tested in Pokhran- I in 1974 had an explosive yield of 12- 15 kt, thermonuclear or hydrogen bombs can be anywhere from 200 kt to a megaton.
Ordinary fission bombs
can be made powerful enough.
Paul Ehrlich, one of the loudest and most influential voices in the movement, proclaims in his textbook-like Ecoscience, "The knowledge needed to construct fission bombs
Except for Edward Teller, the General Advisory Committee of the Atomic Energy Committee voted against attempting to develop a hydrogen bomb on the ground that it would be a much less efficient use of fissionable materials than ordinary fission bombs
The Soviets had been working on fission bombs
for years, however, and were clever enough to gain knowledge of some of the American techniques.