Plutonium was delivered to Los Alamos in the form of what was found to be a mixture of plutonium trifluoride (PuF3) and plutonium tetrafluoride (PuF4). Work with plutonium was carried out in gloveboxes for safety reasons. The metallurgists figured out how to purify the plutonium, and found that heating it to 250° allowed them to work it in the malleable γ phase. It was also found that alloying it with 3 percent gallium would stabilize it in the δ phase. When plutonium at last began to arrive in quantity from the Hanford Site in February 1945, they were ready for production. In a race against the clock, the metallurgists produced plutonium spheres for the Trinity nuclear test by 23 July 1945.