Toxic Polyneuropathy Produced by Methyl N -Butyl Ketone

Abstract

A polyneuropathy affecting a large number of workers was recently observed at a plant producing plastic-coated and color-printed fabrics. Epidemiological data suggested strongly that methyl N-butyl ketone (MBK) was responsible for the outbreak. This hypothesis is now supported by the development of a peripheral neuropathy in chickens, rats, and cats exposed to MBK at atmospheric concentrations of 200 to 600 parts per million, 24 hours per day, 7 days per week. Although the animals were exposed continuously and the affected workers were exposed intermittently, the averages of the total number of hours of exposure for development of the peripheral neutropathy in the animals and workers were remarkably close.

Clinical neurological findings among car painters exposed to a mixture of organic solvents.

“…In contrast to the results reported by Yamamura (33), Cianchetti et al (5), Mendell et al (21), and Allenet al (1), no signs were found that indicated lesions in the peripheral motor system. In the other studies the exposure was n-hexane and/or methyl butyl ketone, and the level of exposure was higher than in our investigation.…”

“…Peripheral neuropathy has recently been studied extensively in typical work environments (1,5,7,14), in "sniffers" (8,17,18,23), and in experimental animals (21,27,29,30). In such studies the causes of neuropathy have been n-hexane (14,27,33), trichloroethylene (7), and methyl butyl ketone (1,21,29,31). For "sniffers" the etiologic agents have often been referred to only as "volatile hydrocarbons" (22,32).…”

Proposed Occupational Exposure Limits for Non-Carcinogenic Hanford Waste Tank Vapor Chemicals

“…In the case of 2-hexanone, there is very robust toxicity information particularly as it relates to neurotoxicity. Subchronic inhalation exposure to 2-hexanone at concentrations ranging from 200 ppm to 1600 ppm is associated with the observance of peripheral neuropathy in chickens, rats, cats, and monkeys (Abou-Donia et al 1985;Mendell et al 1974;Spencer et al 1975;Duckett et al 1974). Johnson et al (1979) reported that rats and monkeys that inhaled 100 ppm of 2-hexanone for 9 months developed abnormal neurophysiologic indicators, and this exposure was equivalent to a daily 8-hour TWA of 75 ppm.…”

2‐Hexanon [MAK Value Documentation in German language, 1975]

“…Dämpfe reizen konzentrationsabhängig die Schleimhäute, besonders die Konjunktiven. Chronische Aufnahme von 2-Hexanon erzeugt -wie Hexan -periphere Polyneuritis, wobei primär die Achsenzylinder, sekundär die Myelinscheiden degenerieren [1,2]. Da Hexan in der Leber überwiegend zu 2-Hexanol metabolisiert wird [3], ist anzunehmen, daß der Polyneuropathie nach Hexan und 2-Hexanon der gleiche Mechanismus zugrundeliegt; über die biochemischen Vorgänge dabei ist nichts bekannt.…”