1. The 1948 Donora smog was an historic air inversion wall of smog that killed 20 and sickened 7,000 people in Donora, Pennsylvania in the United States, a mill town on the Monongahela River, 24 miles southeast of Pittsburgh.

  2. The Organisation for Economic Cooperation and Development is set up in Paris as part of the Marshall Plan. It has an environment department, which deals above all with the relationship between economic activity and the environment. The OECD regularly publishes reports on the environment in OECD countries and other studies.

  3. Invention of 2,4,5, trichlorophenoxyacetic acid. During the Vietnam War (1965-1971), it is used as a defoliant under the codename Agent Orange. It is expected that contaminated soil will need over a century to regenerate.