The toxicity of trimethylarsine: an urban mythw

In environmental terms, the 19th century was the age of arsenic. The uses of this element are almost too numerous to mention—embalming, cosmetics, glass and gunshot manufacture, pyrotechnics, taxidermy, weed and rodent control, and particularly in medicine, both by prescription and self-medication. Arsenic was characterized as a ‘‘therapeutic mule’’. For centuries, it was used for murder being known in France as ‘‘poudre de succession’’ (inheritance powder); the name arsenic is essentially synonymous with poison. However, in areas such as the Austrian province of Styria, arsenic was eaten, as the oxide or sulfide, to give freshness and beauty to the skin, to enhance sexual potency and to improve breathing and stamina in mountain climbing. In 1775, Scheele discovered copper arsenite, CuHAsO3, a green pigment, known eponymously as Scheele’s Green. A related compound, copper acetoarsenite, Cu(CH3COO)2 3Cu(AsO2)2, acquired a variety of names—Schweinfurt Green, Mitis Green, Vienna Green, etc. These pigments found extensive use for coloring wallpapers, cloth and tapestries, various wrappings, children’s toys and even for foodstuffs (e.g, confectionery, blancmange). Europeans, and to a lesser extent Americans, in the 19th century were living in a green environment, provided by green pigments based on arsenic, but in no way related to modern concepts for the adjective, green. Early in the 19th century, it appeared that there was a connection between ill health, possibly death, and habitation in rooms containing arsenic-coated wall coverings, especially if the rooms were damp. In a newspaper letter of 1839, the famous chemist, Leopold Gmelin, strongly warned against the dangers of arsenical pigments on wallpapers. He had observed an adverse, mouse-like odor in rooms containing them, especially those facing to the North, which he attributed to a volatile arsenic compound, ‘‘alkorsin’’—it is probable that he intended alkarsin, dimethylarsinoxide, (CH3)2As–O– As(CH3)2. Other authors reported the odor as leek-like. An alternative possibility was that arsenic-containing particles were flaked from the walls as a poisonous dust. Over the years an extensive dust/gas controversy developed: was the poisoning due to formation of a toxic gas or to inhalation of dust particles? The early literature has been reviewed. Some of the reported events were truly bizarre. For example, in the USA, a family slept in a house where the bedrooms had been cleaned with a solution of arsenic mixed with naphtha and turpentine. Perhaps it is not surprising that they were seized the next day with symptoms of acute arsenic poisoning. One wonders where arsenic obtained a reputation as a cleaner, and what happened to whoever did the cleaning. This article is concerned with the possible toxicity of an arsenical gas. However, the dust theory played a role in rather more recent times. The USA ambassador to Italy, Clare Booth Luce, had to resign her position in 1956 on account of arsenic poisoning. She had slept at the Embassy in a room with a ceiling decorated with arsenic-laden materials. A washing machine on the floor immediately above caused vibrations and lead arsenate particles fell as a ‘‘gray dust’’. A certain irony has been noted: she and her husband, Henry Luce, had been dubbed ‘‘Arsenic and Old Luce’’.