Registration Dossier

Administrative data

Endpoint:
epidemiological data
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non GLP, non guideline, human workplace investigation, minor restrictions in design and/or reporting but otherwise adequate for assessment.
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
publication
Title:
Vinyl acetate; a study of chronic human exposure
Author:
Deese DE & Joyner RE
Year:
1969
Bibliographic source:
Am Ind Hyg Assoc J. Vol 30, pp 449-457

Materials and methods

Study type:
case control study (retrospective)
Endpoint addressed:
skin sensitisation
repeated dose toxicity: inhalation
Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
A retrospective case control study of vinyl acetate chemical operators who had been exposed to levels of vinyl acetate in air of 5 to 10 ppm for a mean period of more than 15 years.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Vinyl acetate
- Physical state: flammable liquid
- Other: no other details reported

Method

Type of population:
occupational
Ethical approval:
not applicable
Details on study design:
HYPOTHESIS TESTED (if cohort or case control study): To identify overt or subtle toxic effects in chemical operators with a long service in vinyl acetate plants.

METHOD OF DATA COLLECTION
- Type: Questionnaire / Record review / Clinical tests:
- Details: Review of latest screening examination; medical records checked for sickness absences / visits to Medical department in study period/ exposure to vinyl acetate during study period; Employee questionnaire to ascertain personal opinions of vinyl acetate.

STUDY PERIOD: January 1, 1964 - December 31, 1968

SETTING: Three vinyl acetate production units of a Gulf Coast chemical plant, Texas, USA


HEALTH EFFECTS STUDIED
- Other health effects: Eye, skin or respiratory irritation, contact dermatitis

Exposure assessment:
measured
Details on exposure:

TYPE OF EXPOSURE: Work place exposure - air concentrations of vinyl acetate were analysed during normal operations and considered representative of the normal operating conditions.

TYPE OF EXPOSURE MEASUREMENT: Area air sampling: Short and long term air samples were collected using impingers and analysed using gas chromatography. Air samples were taken at 3 to 6 designated sites in each of the three production units on two separate sampling occasions, approximately one month apart. The total sampling time represented by these samples was more than 18 hours.

EXPOSURE LEVELS:
Concentrations of vinyl acetate in air ranged from 0 to 49.3ppm with a mean of 8.6 ppm. 83% of these values were below 10 ppm. Estimated exposure levels for the duration of service were 5 to 10 ppm vinyl acetate.
The time-weighted average exposures calculated for operators in process units A, B, and C were 8.2, 5.2, and 7.7 ppm, respectively.
These values do not reflect abnormal and in-frequent exposures, which arose during certain maintenance operations, particularly the opening of a hopper door to unplug material flow (samples collected from the breathing zone at these times were 123.3, 125.6 and 326.5 ppm).

EXPOSURE PERIOD:
Since the operating conditions, process methods and equipment had been unchanged in the previous 5 years, the analytical concentrations determined were considered representative of the long term exposure of the operators.

Results and discussion

Results:
Comparison of the multiphasic examinations of the vinyl acetate workers and the control workers showed no differences between the groups.
Review of medical records over the period 1964-1968 showed no evidence of any detrimental effects on health that could be attributed to vinyl acetate exposure.
In the questionnaire of their personal opinion of vinyl acetate:
- 13 workers reported that under normal working conditions, they were not bothered by vinyl acetate, the other 8 commented on odour, fumes, skin / lung irritation and skin rash.
- 15 workers said they did not experience skin, eye or nose irritation to a significant degree; the remaining 6 said they did.
- 18 workers said it had not caused dermatitis or skin burns; 1 said it had, one said dry skin and the other didn't understand the question.
- when asked for any other comments, 1 complained that breathing fumes hurt his chest and another said he liked the odour.
- 16 of the workers had worked with vinyl acetate for more than 15 years, 6 for more than 20 years and only 3 had worked for 2 years or less.
Confounding factors:
Multichemical exposure and smoking were possible confounding factors but the matched controls would also have been exposed to other chemicals but did not show clinical effects of systemic chemical toxicity.
Strengths and weaknesses:
Long term exposure of the vinyl acetate workers is a strength of this study, 16 of the subjects had worked with the chemical for more than 15 years.
The number of subjects is quite small (21 operators).

Applicant's summary and conclusion

Conclusions:
A case-control study of 21 long-term vinyl acetate chemical workers revealed no chronic effects at the long-term levels of 5 -10 ppm vinyl acetate.
Executive summary:

In a case-control study of vinyl acetate chemical operators in 3 production units of a Gulf Coast chemical plant, concentrations of vinyl acetate in air (under normal working conditions) gave estimated exposure levels of 5 to 10 ppm vinyl acetate for the duration of their service. The mean service length of the 21 operators was 15 years and from review of medical records, recent multiphasic examinations and personal questionnaires, there was no evidence to suggest any chronic effects of vinyl acetate at the long-term levels of 5 -10 ppm.