Don’t Sing the Blues for Indigo

In his review of Manlio Argueta’s “Cuzcatlan” (The Book Review, June 14), Prof. Raymund Paredes states that “Argueta notes with particular vehemence the devastating consequences of the cultivation and processing of indigo . . . which early proved to be a lethal carcinogen.” While the diversion of land to indigo-producing plants may well have had “devastating consequences,” the assertion of the last clause is false. Indigo has not proved early, late or at any other time during its 4,000-year use as a dye to be carcinogenic.

The proscription of indigo in Northern Europe during the 16th and 17th centuries, supposedly on health and safety grounds, was in fact only an attempt to protect growers of the native woad plant, which yields the same dye. Indigo was used for many years for dyeing naval uniforms after Britain adopted a standard “navy blue” uniform in 1745. In tropical America, indigo’s use as a dye predates contact with Europeans (evidence from Inca graves). Finally, indigo is the dye of blue jeans; I have personally seen designer jeans labels saying “dyed with natural indigo” (although synthetic but chemically identical material is usually cheaper).

Whatever the economic or symbolic import of indigo production, it is not even incidentally a kind of chemical class warfare. A material in direct contact with the skin of hundreds of millions of people every day does not become a health hazard solely on the assertion, even “with particular vehemence,” of an angry author.

JAMES B. ELLERN

Senior Lecturer

Chemistry Department, USC