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Diss Factsheets

Toxicological information

Exposure related observations in humans: other data

Administrative data

exposure-related observations in humans: other data
Type of information:
experimental study
Adequacy of study:
supporting study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference Type:
Occupational depigmentation due to 4-tertiary catechol (TBC)
Gellin GA, Possick PA, Davis IH
Bibliographic source:
Journal of Occupational Medecine, Volume 12 n°10, 386-389

Materials and methods

Type of study / information:
The occupational depigmentation was investigated.
Endpoint addressed:
not applicable
Principles of method if other than guideline:
Industrial hygiene (depigmentation in humans workers)
GLP compliance:

Test material

Constituent 1
Chemical structure
Reference substance name:
EC Number:
EC Name:
Cas Number:
Molecular formula:
Details on test material:
4-tert-butylpyrocatechol (4-TBC), no data available


Ethical approval:
not specified
Details on study design:
This study was initiated during the summer of 1968 as result of the diverse opinions given by two physicians as to whether occupational factors were responsible for the depigmentation noted on the hands of a 26-year-old white factory worker. He worked in the actual tappet assembly operation, which employed 75 workers, 70% to 80% of whom were women. Although he alleged that half the workers had similar depigmentation, just three co-workers, 2 men and 1 woman, and all Caucasians were noted to have depigmented skin.
Exposure assessment:
not specified
Details on exposure:
Case 1: A 41-year-old woman had been a tappet assembler for over 10 years. After a thermal burn on her forearms, she noted depigmentation about the elbows. There has been progressive pigment loss since then. Her family history was negative for skin disease and vitiligo. When seen, she had well-demarcated and confluent areas of depigmentation involving 75 per cent of her body surface, including scalp, eyelids and forearms.
Case 2: A 33-year old man had been a tappet assembler for 5 1/2 years. Only one occasion has he worn protective gloves. Throughout this period he has periodically had recurrent hand dermatitis. He first noted a depigmented area on the right cubital fossa. Within months other areas on his upper limbs lost pigment. No family member has had vitiligo. When seen, he had sharply outlined depigmented areas over the hands, finger webs, flexor forearms, right cubital fossa, eyelids and lower abdomen. Ill-defined hypopigmentation affected the prepuce.
Case 3: A 26-year-old man became a tappet assembler in 1963. During 1965 he had a hand dermatitis lasting several months. On healing he noted absence of normal skin color, which has remained unchanged. No other areas on his body have become depigmented. There was no personal or family history of atopy, skin disease or pigmentation abnormalities. When seen, there was mottled and asymmetrical depigmentation on the dorsa of the fingers, finger webs, palms, and flexor forearms.
Case 4: A 29-year old tappet assembler developed hand dermatitis during his initial months on the job. He subsequently started to wear gloves. As the rash healed, the normal pigmentation failed to reappear. A brother had asthma and a "light-colored rash" on his trunk (possible tinea versicolor). When seen, he was suntanned, robust individual with confluent, nonatropic, depigmented skin on his fingers, palms and in the axillae. There was ill-defined hypopigmentation on the bearded area of the face and neck.

Other workers: Approximately 60% of the workers had had dermatitis (redness, blisters, scaling, and fissuring) on the hand from tappet assembly. Those affected wore no gloves. From 10% to 15% of the assemblers (9 or 10 of the 75) have some dermatitis on hands and/or forearms on any given day. No other workers were seen with depigmentation.

The four affected worked were given a patch test using material from the rubber gloves worn at work, 4-TBC 0.1% in acetone.

Results and discussion

4-TBC gave positive responses in three of the four workers. In one of the three workers (Case n°4), the positive reaction subsided leaving a 21 x 22 mm area of depigmentation, lasting for 20 months of observation.

Applicant's summary and conclusion

4 workers among 75 at risk had acral depigmentation. In three the depigmentation affected other parts of the body. All had prior dermatitis, a problem affecting as many as 60% of co-workers who wore no protective clothing.