Toxicological Review of n-Hexane (CAS No. 110-54-3) (PDF)

workers were also exposed to lead (0.6–8.2 µg/g) and mercury (0.05–0.95µg/g) in the printing
inks. The mean TWAs for n-hexane in air samples taken at the plant was 63 ppm (range 30–110
ppm) for general air and 132 ppm (range 80–210 ppm) for breathing zone air of the offset
printers. The findings from the neurological examination of these workers were compared with
the neurological findings of 20 age- and gender-matched unexposed controls. Among the 56
printers, 10 were asymptomatic and showed no clinical findings (classified as healthy workers);
26 were asymptomatic, but had subclinical nerve conduction deficits (classified as subclinical
workers); and 20 were symptomatic for peripheral neuropathy by clinical and electrophysical
findings (classified as symptomatic workers).
No relationship was observed between length of employment and the development of
neuropathy. Workers that were symptomatic reported experiencing symptoms in the upper and
lower extremities such as numbness (8/20 and 14/20, respectively), paraesthesia (5/20 and 13/20,
respectively), pain (2/20 and 9/20, respectively), and weakness (7/20 and 15/20, respectively) of
the feet and distal portion of the legs. Subjects in the symptomatic group had more severe
symptoms in the lower than the upper limbs, and sensory disturbances usually appeared before
motor disturbances. Four workers who did not use gloves when cleaning the roller blanket
showed symptoms in the upper limbs first. No autonomic neuropathy was reported by any
worker. Clinical symptoms were not reported for healthy workers or for those who were
asymptomatic, but classified as having subclinical neuropathy. The authors also measured
electrophysical deficits in each group of workers (Table 4-5). In healthy workers, there was a
decreased amplitude of the median nerve SNAP compared with controls. Subclinical workers
had more significant decrements in the SNAP amplitude and MCV. There was also a mild
reduction in mean MAP amplitudes and prolongation of mean DL. The symptomatic workers
were reported to have a marked reduction in mean SNAP, MAP, and MCV and prolonged DL.
Table 4-5. Nerve conduction study findings in printers with n-hexane-induced
polyneuropathy
Type of nerve
conduction study
Control
(n = 20) a
Healthy worker
(n = 10) a
Amplitude of SNAP (:V)
Subclinical worker
(n = 26) a
Symptomatic
worker (n = 20) a
Median 37 (11) 27 (6) b 24 (8) b 15 (5) b
Ulnar 15 (4) 14 (3) 12 (5) 7 (4) b
Sural 24 (10) 22 (6) 18 (7) b 11 (8) b
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