A researcher and teacher specializing in immunotoxicology, Allen once described himself as “an inveterate social-deviant trouble-maker with a sense of humor about it.” He was born in Chicago, Illinois, and graduated from Bowen High School. At Reed he wrote his thesis, “The Synthesis and Reactions of a [Beta]-aryl Ether Lignin Model Compound,” with Prof. Marshall Cronyn [chemistry 1952–89] advising. Years later, the things he most remembered about Reed were “its ideal of learning (making knowledge your own), and the patience of assorted faculty with this crazy kid from industrial Chicago.” He got his PhD from the Massachusetts Institute of Technology, received postdoctoral fellowships at the University of Edinburgh and MIT, and researched and taught at MIT, Sloan-Kettering, and State University of New York Upstate Medical University. He was the author of more than 70 reviewed papers and was cited thousands of times. Allen also advised multiple Environmental Protection Agency Superfund committees in New York City and State. An antiwar and environmental justice organizer in Boston, New York City, and Syracuse, he was a tireless crusader for civil rights, economic justice, public health, and public education. He is survived by his son, David.