The fact that Currie joined Pfizer during World War I was no coincidence. Pfizer officials, led by John Anderson, realized that the company had to reduce its vulnerability as an importer of raw materials. The war cut off the supply of Italian citrus, and all raw material deliveries from Europe were threatened by the German submarine blockade. Supplying medicines and chemicals for the war helped the company survive, but overall sales declined. Now, more than ever, Pfizer needed to find ways to produce citric acid without using citrus.