Occurrence and concentrations of isothiazolinones in detergents and cosmetics in Switzerland

Abstract

SummaryBackground. In recent years, the frequency of contact allergy to isothiazolinones has increased alarmingly in Europe, but only limited data are available on concentrations of isothiazolinones in consumer products. Objectives. To examine the current frequency of isothiazolinones [methylisothiazolinone (MI), methylchloroisothiazolinone (MCI), benzisothiazolinone (BIT), and octylisothiazolinone (OIT)] in a wide array of detergents and cosmetics relevant for the Swiss population. Methods. By means of a market survey, the occurrence of isothiazolinones was investigated in 1948 consumer products. Of these, 88 products were analysed by liquid chromatography-high-resolution mass spectrometry after ultrasonic extraction. Results. Only 7.6% of all cosmetics contained isothiazolinones, but the prevalence in detergents was much higher (42.9%). The measured concentration ranges in detergents were 4.3-10, 3.5-279, 3.8-186 and 7.9 ppm (one product only) for MI, MCI, BIT, and OIT, respectively. For cosmetics, these were 1.3-133 and 4.8 ppm (one product only) for MI and MCI, respectively. Conclusions. Our study has shown that high concentrations of isothiazolinones (including MI) can be found in a large variety of products, in particular in detergents. Therefore, the safe use of these preservatives should be re-evaluated by including detergents in the exposure assessment.

Methylisothiazolinone in cosmetic products in Tunisia

“…Our results are in accordance with those previously reported in the literature prior to regulations of MI . This allergen was present in many products, primarily for adults, but also in some for children .…”

“…Methylisothiazolinone (MI) frequently causes allergic contact dermatitis . In 2017, MI was banned in leave‐on cosmetics in the European Union and only a concentration of 15 ppm was allowed in rinse‐off products . In Tunisia, there is no restriction of the use of MI in cosmetics.…”

Methylisothiazolinone contact allergy in Croatia: Epidemiology and course of disease following patch testing

“…A higher proportion of detergents (42.7%) than of cosmetics was found to contain isothiazolinones, most often benzisothiazolinone (BIT), in 31.2%, followed by MI in 31.1% and MCI in 9.9%. High concentrations were particularly found in detergents . These results connect well with the patterns of causative products in the current investigation.…”

“…In a recent Swiss market survey of 1948 consumer products, it was shown that only 7.6% of all cosmetic products were found to contain isothiazolinones. Shampoo was the product category with the highest percentage of isothiazolinones (33.8%), followed by shower gel (13.3%), and wet wipes (11.6%) . A higher proportion of detergents (42.7%) than of cosmetics was found to contain isothiazolinones, most often benzisothiazolinone (BIT), in 31.2%, followed by MI in 31.1% and MCI in 9.9%.…”

Isothiazolinones are still widely used in paints purchased in five European countries: a follow‐up study

“…The isothiazolinones methylisothiazolinone (MI), methylchloroisothiazolinone (MCI), MCI/MI 3:1, benzisothiazolinone (BIT), octylisothiazolinone (OIT) and dichlorooctylisothiazolinone (DCOIT) (see Table for further information) are preservatives used in a wide range of industrial chemical products (as biocides) and partly (MCI and MI) in cosmetic and household products, owing to their activity against bacteria and fungi .…”