04/21/1968
https://www.presidency.ucsb.edu...
"Research continues to uncover new uses for this durable and versatile product to satisfy exacting military and civilian requirements."
"It supports our buildings, spans our rivers, arms our fighting men."
"It has helped to make American productivity and technology the wonder of the world."
"This vital product which we produce in unmatched abundance is basic to our economy and essential to our security."