§ Mr. D. E. Thomasasked the Secretary of State for Energy if he will publish a 126W methods is not precise but some of these tests have been at levels near to the threshold of 150 kilotons set in the 1974 threshold test ban treaty, which has not, however, yet been ratified by the USA or the USSR. This threshold is about 10 times greater than the yield of the weapon exploded at Hiroshima which was 12.5 kilotons.