In late 1916 he was sent to sabotage the Romanian oil fields ahead of a German advance. Colonel Norton-Griffiths used such techniques as dumping cement down the wells, filling tanks with nails, and emptying storage wells and then setting them on fire. He was able, almost single-handedly, to destroy seventy refineries and 800,000 tons of crude oil. General Ludendorff of the German army was later quoted as saying, "We must attribute our shortages in part to him." German efforts later got some of the Romanian fields back online for the war effort, but they were never able to recover fully.