Geigy and DDT

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Geigy remained primarily a dye company until the 1930s, when it diversified into textile auxiliaries, agricultural chemicals and pharmaceuticals. Its most famous discovery came from its research on insecticides for the protection of textiles against moths. In 1939, the Geigy chemist Paul Hermann Müller discovered the insecticidal properties of dichlorodiphenyltrichloroethane, a compound that had been synthesised in the nineteenth century but whose properties were unknown. The compound, known as DDT, proved highly effective against insects and was cheap to produce.¹

During the Second World War, DDT was used on a large scale by the Allied armies to combat lice, which transmit typhus, and mosquitoes, which transmit malaria. It prevented epidemics among soldiers, refugees and civilians and saved hundreds of thousands of lives. After the war, it was used in campaigns to eradicate malaria in many countries and in agriculture throughout the world. Müller received the Nobel Prize in Physiology or Medicine in 1948.

The success of DDT was followed by its fall. In the 1950s and 1960s, scientists observed that DDT accumulated in the food chain, harmed birds and other wildlife and persisted in the environment for decades. Rachel Carson's book Silent Spring, published in 1962, made the dangers of DDT and other pesticides known to a broad public and is regarded as a founding text of the modern environmental movement. DDT was banned for agricultural use in the United States in 1972 and in many other countries. Today its use is restricted by the Stockholm Convention on Persistent Organic Pollutants of 2001 to the control of disease vectors.²

The history of DDT shows the ambivalence of chemical innovation: a discovery that saved many lives also caused lasting environmental damage, while the assessment of its benefits and costs changed fundamentally within a generation. For a financial centre whose largest companies are chemical and pharmaceutical groups, this ambivalence has practical consequences. The liabilities arising from past products and contamination, the regulatory risks of new products and the reputational risks of environmental damage are factors that investors, lenders and insurers must assess. The legacy of DDT and of other chemicals produced in Basel is part of the history that the Basel companies carry.

Notes

1. On Paul Hermann Müller (1899–1965), who discovered the insecticidal properties of DDT at Geigy in 1939, and his Nobel Prize in Physiology or Medicine in 1948, see HLS, article "Müller, Paul Hermann". To be verified. ↩
2. Rachel Carson, Silent Spring, Boston 1962; US ban on agricultural uses of DDT in 1972; Stockholm Convention on Persistent Organic Pollutants of 22 May 2001 (SR 0.814.03), Annex B (DDT). To be verified. ↩

For general information only. This article does not constitute legal or tax advice, does not replace advice on an individual case and creates no lawyer-client relationship. It reflects the legal position as of August 2025.