Companies placing products on the market are responsible for ensuring that those products are safe for their intended purpose and for foreseeable misuse. Regulations make sure that is the case. It is very unlikely but nevertheless possible that certain ingredients could cause an allergy. In cleaning products, fragrances and preservatives are considered to be the main substances that could cause an allergy.
Preservatives are included in detergent and cleaning products to ensure that the product quality is maintained and does not degrade in any way. There are a very limited number of cases where people have experienced an allergic reaction to preservatives in detergents. Preservatives are always indicated on the label using their INCI* name, enabling you to choose the right product.
Fragrances that are found in many consumer goods are usually actually made up of several different fragrance ingredients. Some have been found to be more likely to cause an allergy than others. European regulations list the 26 most common fragrance allergens and require that, if any of them are used in a product to the extent that they make up more than 0.01% of the product by weight, they need to be named on the product label. This allows anyone who knows they have an allergic reaction to such a substance, to make an informed decision as to whether this product is appropriate for them.
INCI is the International Nomenclature of Cosmetic Ingredients. The use of INCI makes it easy for consumers in all countries, irrespective of language differences, to easily recognize the ingredients present. On the label, the names of substances are written with INCI.