Late in his senior year, Welch was accepted to University of Massachusetts Amherst, where he studied chemical engineering. Welch worked in chemical engineering at Sunoco and PPG Industries during his college summers.[5] In his sophomore year, he became a member of the Phi Sigma Kappa fraternity.[5] Welch graduated in 1957 with a Bachelor of Science degree in chemical engineering, turning down offers from several companies in order to attend graduate school at the University of Illinois at Urbana-Champaign.[5][6] He graduated from the University of Illinois in 1960 with a Master's degree and a PhD in chemical engineering.[7][8]