1970 President Richard Nixon’s executive order launches the Environmental Protection Agency.

1970 Congress passes the Clean Air Act, the first of many environmental regulatory laws in the 1970s.

1972 Paul Berg performs the first successful recombinant DNA experiment by assembling DNA molecules carrying genes from different organisms.

1972 Robert Burns Woodward (pictured) and Albert Eschenmoser report the first total synthesis of vitamin B-12.

1973 Paul C. Lauterbur describes the medical imaging technique MRI (magnetic resonance imaging).

1974 Mario J. Molina and F. Sherwood Rowland publish their theory that CFCs lead to atmospheric ozone depletion.

1975 Césaré Milstein and Georges Köhler devise a strategy for producing monoclonal antibodies.

1975 Primo Levi publishes “The Periodic Table,” his iconic collection of autobiographical short stories.

1976 Herbert W. Boyer and Robert A. Swanson set up Genentech, the first biotechnology company.

1976 Congress passes the
Toxic Substances Control Act to regulate the chemicals in everyday products.

1976 First 2-D NMR experiment is published by Walter P. Aue, Enrico Bartholdi, and Richard R. Ernst.

1977–78 Bruce N. Ames and Arlene Blum demonstrate that two flame retardants in children’s pajamas have mutagenic properties.

1978 Chemical waste leaking from a former industrial dump prompts the Love Canal, N.Y., neighborhood evacuation.

Download C&EN 90th Anniversary Poster Timeline (pdf)