“I had the ultimate deferment...... I was declared essential to the war effort”
That was true for many men of the so-called Greatest Generation including, initially, my father. In fact, the original purpose of the Selective Service Act of 1940 was to keep certain men (with skills critical to the preparation for war) out of the service. It was only well into the war (late 1943 or early 1944) when the number of eligible volunteers fell substantially short of the number of servicemen required by the military.
I have a very good friend who’s father was a chemical engineer working for a company involved in many very secret war effort projects.
He was chomping at the bit to go to war. By 1943, they finally let him go and he was inducted as a Naval Lt. He had barely made it into his first assignment when he got orders to return home.
The company had enough authority to tap miltary personnel for their secret projects. He was placed in a position at Oak Ridge working on the uranium separation work there