Ammonium hexafluorosilicate

Exposure related observations in humans: other data

Administrative data

Endpoint:

exposure-related observations in humans: other data

Type of information:

other: Case report

Adequacy of study:

supporting study

Study period:

Publication date - 07 September 1985

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:

Unnamed

Year:

1985

Report date:

1985

Materials and methods

Type of study / information:

A case report describing irritant reactions in a foam rubber carrier (worker)

Endpoint addressed:

skin irritation / corrosion

Test guideline

Qualifier:

no guideline followed

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

disodium;hexafluorosilicon(2-)

Cas Number:

16893-85-9

Molecular formula:

Na2SiF6

IUPAC Name:

disodium;hexafluorosilicon(2-)

Specific details on test material used for the study:

Name: Sodium hexafluorosilicate.

Method

Ethical approval:

not applicable

Details on study design:

A case is reported of a foam rubber carrier with pustular lesions on the arms, wrists, thighs and trunk. Scratch and patch testing with the foam rubber components was carried. Sodium hexafluorosilicate (Na2SiF6), one of the ingredients of the foam rubber, was suspected for these reactions, which was investigated in a study with rabbits.

Details on exposure:

Case Report
A 23-year-old man with no history of atopy or other skin disease had skin lesions for 5 weeks, They consisted of diffuse, poorly delineated, erythematous plaques with lichenoid papules and large pustules, some of which were umbilicated with superficial central necrosis. They were mainly on the flexor forearms and wrists above the gloves, on the front of the thighs and sparsely on the trunk. The patient had slight pain but no itching. He related it to his work, since the lesions occurred 1 week after he began work in a foam-rubber plant and were located only where he had contact with "wet" foam-rubber materials (pillows, mattresses). They improved without treatment at weekends and during short vacations, leaving only punctate pigmentation. They would recur on the second day after he returned to work and increase in intensity as the week proceeded.

Many of his workmates had similar, though less pronounced, complaints (erythema, desquamation, slight itching), particularly towards the end of the week.

Results and discussion

Results:

Investigations:
(i) Bacteriological cultures were taken from the pustules twice but were negative; mycological cultures yielded no growth.
(ii) Biopsy showed a sub-corneal vesicle filled with polymorphonuclear cells, cellular debris, and fibrinous exudate. This is similar to pustular psoriasis or an acute inflammatory response to trauma and infection. In the dermis, there was a discrete perivascular in­filtrate with polymorphonuclear cells. PAS stain was negative. There were no signs of allergic or irritant dermatitis, folliculitis, or miliaria.

Patch testing with the standard series was negative after 48 and 96 h. Patch tests with the raw material (liquid latex, as is and open test) and most of the additives (sulphur, 2.5% pet.; sodium hexafluorosilicate, 0.5% aq.; zinc di-ethyldithiocarbamate, 1 % pet.; 1,3-diphenyl-guanidine, 1% pet.; carboxymethylcellulose, 3% pet.) and the rinse water (pH =neutral) were negative after 48 and 96 h.

Of the component parts of the foam-rubber objects, sodium hexafluorosilicate, which is a gelifier essential for the structural formation of the foam rubber, was the likely cause since fluorides (ammonium fluoride NH4F, and so­dium fluoride NaF) are known pustulogens.

(iv) Scratch testing with sodium hexafluoro-silicate (Na2SiF6) (2% aq.) and the rinse water were negative after 48 and 96 h. A 48-h use test (3 applications a day on the forearm) yielded only slight itching and barely visible papules to the rinse water.

(v)  Animal testing on rabbits was performed with Na2SiF6 in the following concentrations: 1%, 5 %, 10%, and 25% (in pet.) and with the rinse water. Pustules were obtained on normal skin with 25% Na2SiF6 (2 out of 10 sites), on stabbed skin with all concentrations, and with the rinse water (3 out of 10 sites).

Applicant's summary and conclusion

Conclusions:

A case was reported of a foam rubber carrier with pustular lesions on the arms, wrists, thighs and trunk. Scratch and patch testing with the foam rubber components to investigate sensitisation/allergic potential was negative. Animal testing revealed sodium hexafluorosilicate (Na2SiF6), one of the ingredients of the foam rubber, to be a pustulogen on previously damaged skin.

Executive summary:

A case was reported of a foam rubber carrier with pustular lesions on the arms, wrists, thighs and trunk. Scratch and patch testing with the foam rubber components to investigate sensitisation/allergic potential was negative. Animal testing revealed sodium hexafluorosilicate (Na2SiF6), one of the ingredients of the foam rubber, to be a pustulogen on previously damaged skin.