Data on the effects of exposure to CS2 are summarized in Table 11.
According to Bittersohl et al. (1972), exposure to CS2 at 300 ppm produces slight symptoms of poisoning after several hours; at 400 ppm, it gives rise to prenarcotic symptoms; at 1,150 ppm for 30 min, it leads to severe forms of poisoning; and at 3,200–3,800 ppm, it is life-threatening. According to Paluch (1954), exposure at 2,000–3,300 ppm leads to narcosis in 30 min, and death occurs after 30–60 min of exposure at 5,000 ppm.
Acute psychosis was a common manifestation of CS2 poisoning in rubber vulcanization plants until this process was discontinued at the end of the nineteenth century. During World War II, many cases of chronic poisoning, in which peripheral neuropathy was the leading complaint, occurred in the viscose rayon industry (Vigliani, 1954). There are several epidemiological reports of occupational disease after low-concentration, long-term exposure to CS2 or a combination of CS2 and hydrogen-sulfide (H2S) (NIOSH, 1977).
Peripheral neuropathy, as revealed by lowering of maximal motor nerve conduction velocities (MCVs), was found in 118 workers (110 controls) exposed at 20–60 ppm for 1–27 yr; exposure was at less than 30 ppm during the last 12 yr (Seppalainen et al., 1972). Similarly, MCVs of peroneal nerves were lowered and abnormal electromyograms were prevalent in a study of 254 subjects (54 controls) exposed at 20–80 ppm for 2–31 yr, with exposure at less than 20 ppm during the last 3 yr (Gilioli et al., 1978). Another study (Knave et. al., 1974) reported lowered MCVs in a group of 51 subjects (52 controls) exposed at less than 20 ppm for 1–30 yr.
CNS effects reported by Styblova (1977) consisted of abnormal electroencephalograms (EEGs) in 33.2% of 250 workers (compared with 6.6% of 61 controls) employed in the production of rayon staple. EEGs were abnormal in 39% of 54 subjects (compared with 12% in controls) exposed at 10–15 ppm for 10–15 yr (Seppalainen and Linoila, 1976).
Psychic effects of CS2 have also been measured epidemiologically. Mancuso and Locke (1972) found an increased risk of suicide among 4,899 viscose rayon workers, and another study (Hanninen et al., 1978) of 206 workers (and 152 controls) found psychomotor disturbances and personality changes indicative of depression. Psychologic testing of 102 workers showed an impairment of intelligence functions and performance tests compared with those in controls (Cassitto et al., 1978).
The exact CS2 concentration necessary to produce neurologic disease in humans is unknown, but Seppalainen and Haltia (1980) stated recently that no new cases had occurred among workers who started their work in the Finnish viscose rayon industry in the late 1960s or thereafter, when airborne CS2 concentrations were mostly below 10 ppm and at times 10–20 ppm. However, mild cases of polyneuropathy appeared in a viscose film factory in Finland, where the mean exposure had remained about the same for 17 yr, and where the Finnish TLV of 10 ppm had frequently been