Page 23 - Eugene Patrick Collins

Bombing photograph of the Deutsche Vacuum oil refinery at Bremen. The crew
bombed from 17,500 Feet. Time over target 10-02 am. Course 078 Degrees. Bomb
load 1 x high capacity 4,000lb ̔ Cookie ̕, 12 x ANM 64 DT (American 500lb bombs)
and 4 x medium capacity 500lb general purpose bombs. T.I.S. indicates the target
indicators dropped by the Pathfinder Mosquitoes.

The American explosives industry was assisting the English Armaments industry in
late 1944 to wars end in supplying 500lb bombs to Bomber Command squadrons.
Simply put, Bomber Command was delivering more bombs than the UK Ordinance
factories could produce, hence the American supplies.

On a footnote,

An American Liberty ship, the SS Montgomery filled with 500lb bombs and other
military ordinance ran aground in the Thames Estuary on 20 August 1944 and to
th
this day poses a danger to the English town of Southend on sea. It is calculated that
if the munitions on board detonated then the explosion would be equivalent to a
small nuclear explosion.

http://en.wikipedia.org/wiki/SS_Richard_Montgomery