Man-made vitreous (silicate) fibres with random orientation with alkaline and alkali earth oxides (Na2O+K2O+CaO+ MgO+BaO) content greater than 18% by weight and fulfilling one of the CLP Regulation Annex VI Note Q conditions

Sensitisation data (human)

Administrative data

Endpoint:

sensitisation data (humans)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1977

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

Patch testing with mineral wool (Rockwool®)

Author:

Björnberg A. and Löwhagen G.-B.

Year:

1977

Bibliographic source:

Acta Dermatovener (Stockholm) 57: 257-260, 1977.

Materials and methods

Type of sensitisation studied:

skin

Study type:

study with volunteers

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: Aluminium patch test according to Fregert

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Reference substance 001

Test material form:

solid: fibres

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Rockwool as commercially available (Rockwool®)
- Uncoated Rockwool
- Uncoated Rockwool without fibres, supplied as powder

Method

Type of population:

general

Ethical approval:

not specified

Subjects:

- Number of subjects exposed: 315
- Sex: Male (124) and female (191)
- Age: 15 - 87 years

Clinical history:

None of the 315 subjects had active eczema at time of testing.

Route of administration:

dermal

Details on study design:

TYPE OF TEST USED
- Patch test (epicutaneous test) according to Fregert

ADMINISTRATION
- Description of patch: Aluminium patch test
- All individuals were tested on normal skin on the upper back
- Tested substances:
1. Rockwool as commercially available
2. Rockwool with the same fibres as in 1 but without chemical additives (uncoated)
3. Rockwool without fibres and without chemical additives, supplied as powder
4. Chemical additives: Phenolformaldehyde resin 5% pet., silicone (gamma-amino-propyl-trietoxysilane) 50% aq., mineral oil 50% o.o. and binder 5% alc. containing free phenol and formaldehyde, barium hydroxide, the silicone compound and ammonium
5. A standard series of allergens: Potassium dichromate 0.5%, paraphenylenediamine 2%, thiurammix 1%, neomycin sulphate 20%, cobalt chloride 1%, benzocaine 5%, nickel sulphate 2.5%, Vioform 5%, colophony 20%, parabens 15%, wood tars 12%, PPD-mix 0.6%, wool alcohols 30%, mercaptomix 1%, coal tar 5%, Sterosan 5%, Perubalsam 25%, naphthylmix 1%, formaldehyde 2%, diaminodiphenylmethane 0.5%, ethylene diamine 1%, chlorocresol 1%
- Testing/scoring schedule: The aluminium patch test according to Fregert was used in all tests, with both fibres and with the allergens, with an exposure time of 48 hours and reading of the results after 72 hours.
- Concentrations: Roughly the same amount of fibres was used in all tests, covering the inner surface of the patch test unit.
- Other: In order to estimate the error of the methods used in the fibre tests, patches were applied symmetrically in duplicate on the right and left side of the upper back.

EXAMINATIONS
- Grading/Scoring system: 0 = normal skin; + = slight erythema or a few solitary pale papules; ++ = erythema, papules, slight infiltration; +++ = erythema, infiltration, papules, vesicles and/or erosions; reaction to allergens was designated as positive or negative
- Statistical analysis: The χ2-test was used. The error of the method was calculated according to Dahlberg, 1948. Values of p<0.05 were considered significant.
- Microscopic examination: Punch biopsies were taken from the centre of the fibre test reaction at 72 hours in 12 patients. They were fixed in formalin and stained with hematoxylin-eosin and van Gieson.
- Series of patients tested:
a) Routine patch testing on Rockwool as commercially available and standard series of allergens with 315 patients (124 men, 191 women)
b) Patch test reaction to Rockwool, uncoated Rockwool and uncoated Rockwool in powder form with 20 patients who initiallly showed strong positive reactions (++, +++) to Rockwool
c) Patch test reaction to chemical additives with the same 20 patients as in (b)
d) Patch test reaction to coated and uncoated Rockwool in duplicate (to assess error of the method in patch tests) with 78 patients

Results and discussion

Results of examinations:

Results of examinations
RESULTS
a) Reactions to Rockwool as commercially available
- Of the 315 patients, 32 (10%) reacted with a + reaction and 47 (15%) with a ++ or +++ reaction
- Macroscopically, a papular-vesicular reaction in some cases simulated a true allergic patch test reaction. In other subjects the picture was dominated by superficial small erosions. Some weak reactions showed a few skin-coloured, often follicular, papules without erythema, while in others there was only slight erythema without papules. Most patients reported itching from strongly positive reactions.
b) Reactions to fibres
Of the 20 previous Rockwool-positive patients retested with different types of fibres, 16 reacted (+ to +++) positively to coated Rockwool and 14 to the uncoated product (difference is not statistically significant). None reacted to Rockwool as a powder without the additives and the fibres.
c) Reactions to standard series of allergens
In the tests with the series of standard allergens the number of allergic reactors among the fibrepositive subjects was not greater than among the fibre-negative subjects.

Any other information on results incl. tables

Table 1 summarises the results of patch testing with coated and uncoated Rockwool and Rockwool as

a powder in 20 patients previously positive to Rockwool.

Table 1: Patch testing in 20 subjects previously positive to Rockwool

Tested substance	No. of positive reactions
Coated Rockwool	16/20
Uncoated Rockwool	14/20
Rockwool as a powder	0/20

Table 2 summarises the results of patch testing with allergens related to the manufacturing of Rockwool.

A few allergic patch test reactions occurred in 20 patients strongly positive to Rockwool in the further tests with the chemical additives used in the coating process. The exceptional positive reaction to the binder in one patient could not be explained.

Table 2: Results of patch testing with additives to Rockwool in 20 patients strongly positive to Rockwool

Tested substance	No. of positive reaction
Binder 5% alc.	1/20
Hardened resin	0/20
Mineral oil 50% o.c.	0/20
Silicone 50% aq.	0/20
Paratertiary butylphenol 1% pet.	1/20
Phenol-formaldehyde 5% pet.	0/20
Formaldehyde 2% aq.	1/20

The error of the patch tests with Rockwool (coated and uncoated) was 25%, when the same subjects were tested symmetrically on the left and right side of the back.

Applicant's summary and conclusion

Conclusions:

It was concluded that the skin reactions in the patch tests with Rockwool seem to be mechanically induced, as only the fibrous products of the mineral gave rise to reactions and not the product in powder form. In addition, the coating of the mineral fibres did not influence skin reactions and no allergic reactions to the chemical additives used in the manufacturing process of Rockwool were observed in the Rockwool-positive subjects.

Executive summary:

Rockwool was tested to determine its ability to sensitise the skin of 315 volunteer subjects using an aluminium patch test. The product was applied for 48 hours to the upper back of the subjects and the sites were evaluated for skin reactions after 72 hours. Of 315 patients, 32 (10%) reacted with a + reaction and 47 (15%) with a ++ or +++ reaction to commercially available Rockwool (coated). 20 persons, who were positively tested, were patch tested again using three different types of Rockwool, namely commercially available coated Rockwool, uncoated Rockwool and Rockwool as powder. As result, 16 and 14 persons reacted positively to coated and uncoated Rockwool, respectively, whereas no subject reacted to Rockwool in powder form. Thus, it was concluded that the skin reactions seem to be mechanically induced, as only the fibrous products of the mineral gave rise to reactions and not

the product in powder form. In addition, the coating of the mineral fibres did not influence skin reactions and no allergic reactions to the chemical additives used in the manufacturing process of Rockwool were observed in the Rockwool-positive subjects.