N-hexane

Epidemiological data

Administrative data

Endpoint:

epidemiological data

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1986

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This study is classified as reliable with restrictions because although a GLP statement and ethical approval was not available the study seemed to be well-conducted.

Data source

Reference

Reference Type:

publication

Title:

An outbreak of n-hexane-induced polyneuropathy among press proofing workers in Taipei

Author:

Wang, JD; Chang, YC; Kao, KP; et al.

Year:

1986

Bibliographic source:

American Journal of Industrial Medicine 10:111-118

Materials and methods

Study type:

cohort study (retrospective)

Endpoint addressed:

neurotoxicity

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Wang et al. (1986) evaluated a group of 59 press proofing workers from 16 factories who were employed for at least 2 months. Two exposure measures using personal air samplers were taken in 14 of the 16 factories. Samples of the bulk cleaning solvents contained concentrations of n-hexane ranging from 10–65%. Referent neurological data were collected from 150 healthy individuals.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

N-hexane

EC Number:

203-777-6

EC Name:

N-hexane

Cas Number:

110-54-3

Molecular formula:

C6H14

IUPAC Name:

hexane

Details on test material:

- Name of test material (as cited in study report): n-hexane
- Analytical purity: cleaning solvents were found to contain n-hexane at concentrations ranging from 10–65%

Method

Type of population:

occupational

Ethical approval:

not specified

Details on study design:

METHOD OF DATA COLLECTION
- Type: other: Air samples, MCV levels and neurological data.
- Details:Two exposure measures using personal air samplers were taken in 14 of the 16 factories. MCVs and neurological exams were conducted.

STUDY PERIOD: not reported

SETTING: occupational exposure in factory

STUDY POPULATION
- Total population (Total no. of persons in cohort from which the subjects were drawn): not provided
- Selection criteria: Press proofing workers employed for at least 2 months
- Total number of subjects participating in study: 150
- Sex/age/race: not provided
- Smoker/nonsmoker: not reported
- Total number of subjects at end of study: 150

Exposure assessment:

measured

Details on exposure:

TYPE OF EXPOSURE: Occupational

TYPE OF EXPOSURE MEASUREMENT: personal air sampling

EXPOSURE LEVELS: Samples of the bulk cleaning solvents were found to contain n-hexane at concentrations ranging from 10–65%.

EXPOSURE PERIOD: not reported

POSTEXPOSURE PERIOD: atleast two years

Results and discussion

Results:

FINDINGS:
MCVs among workers exposed to n-hexane were consistently lower than among controls.
While no association was found with length of employment, statistically significant associations existed between frequency of polyneuropathy and abnormal MCV and n-hexane concentration in the cleaning solvents and between the frequency of polyneuropathy and n-hexane air concentrations.

INCIDENCE / CASES
- Incidence: The results of the neurological examination identified 15 workers with polyneuropathy and two asymptomatic workers with abnormal MCVs. All but one of these workers were employed in factories that used solvents with n-hexane concentrations in excess of 50%.


OTHER OBSERVATIONS:
Samples of the bulk cleaning solvents were found to contain n-hexane at concentrations ranging from 10–65%.
Among the workers with polyneuropathy, a high percentage worked in factories with n-hexane air concentrations greater than 100 ppm. However, a significant reduction in the MCV was found among workers exposed to air concentrations less than 25 ppm, a result that the authors considered to be related to the prolonged exposure due to overtime work.

Applicant's summary and conclusion

Conclusions:

The neurological examination identified 15 workers with polyneuropathy and two ashymptomatic workers with abnormal MCVs. All but one of the workers were employed in factories that used solvents with n-hexane concentrations in excess of 50%.
No association was found with length of employment, statistically significant associations existed between frequency of polyneuropathy and abnormal MCV and n-hexane concentration in the cleaning solvents and between the frequency of polyneuropathy and n-hexane air concentrations. However, a significant reduction in the MCV was found among workers exposed to air concentrations less than 25 ppm, a result that the authors considered to be related to the prolonged exposure due to overtime work.

Executive summary:

Study authors evaluated a group of 59 press proofing workers from 16 factories who were employed for at least 2 months. All but four of these workers had regular contact with solvents in the process of cleaning the rollers. Two exposure measures using personal air samplers were taken in 14 of the 16 factories. Referent neurological data was also collected from workers and healthy individuals. MCVs were also collected from workers exposed to n-hexane.

Samples of the bulk cleaning solvents were found to contain n-hexane at concentrations ranging from 10–65%. Referent neurological data were collected from 150 healthy individuals (50 persons from three age groups, 10–35, 36–50, and 51–80 years, sex not stated). MCVs among workers exposed to n-hexane were consistently lower than among controls. The results of the neurological examination identified 15 workers with polyneuropathy and two asymptomatic workers with abnormal MCVs. All but one of these workers were employed in factories that used solvents with n-hexane concentrations in excess of 50%.

While no association was found with length of employment, statistically significant associations existed between frequency of polyneuropathy and abnormal MCV and n-hexane concentration in the cleaning solvents and between the frequency of polyneuropathy and n-hexane air concentrations. Among the workers with polyneuropathy, a high percentage worked in factories with n-hexane air concentrations greater than 100 ppm. However, a significant reduction in the MCV was found among workers exposed to air concentrations less than 25 ppm, a result that the authors considered to be related to the prolonged exposure due to overtime work.