Protease is a protein splitting enzyme, this is used in for instance detergents in order to dissolve protein-containing stains such as sweat, grass and blood.
The EU generally considers enzymes to be potential respiratory allergens, which pose a work environment risk relative to causing allergies. The EU, however, simultaneously considers the risk of allergies to be minimal relative to ordinary consumer usage of enzyme-containing detergents etc.
Low concentrations of the enzyme may, therefore, be used in detergents, which have been certified by Asthma-Allergy Denmark.
The low concentrations equally ensure that inhalation due to dispensing, as well as residual concentrations of dissolved detergents after wash do not cause irritation or allergies.
I.e. mediated allergy, which causes hay fever and asthma symptoms towards enzymes is rare. This knowledge is based on data material from 15,765 people gathered over a 40 year period as well as a literature examination from 2010. A total of 37 people had developed allergies towards enzymes, of which the most of these cases had arisen before 1977 and thus with people, who had been exposed to high exposure concentrations. There were not found any symptoms nor any direct linkage to exposure to laundry or detergents.
Subtilisin (protease) may, however, cause skin and eye irritation if contact occurs. Tests have shown that watery solutions with up to 0.2% active subtilisin does not cause irritation on intact skin. Higher concentrations of proteases cause skin irritation. Irritation is, however, not considered to be reason for concern due to the low concentrations, which are used and the product types, which subtilisin is found in.
Multiple allergy tests have been negative – including patch tests on workers, who have been exposed to concentrated subtilisin for a longer period of time. Allergy data, therefore, shows no signs that the protease is a contact allergen.
As mentioned, the substance is a potential respiratory allergen, which was determined in 1969, where subtilisin showed to have harmful effects on the respiratory systems of workers. Back then you used subtilisin as a dry powder contrary to today, where subtilisin is found in non-powdery and coated granula. Respiratory allergies due to subtilisin are not reason for concern in ordinary use of enzyme-containing detergents nowadays.