I’ve just been updating our directory of safe paints, specifically with regard to those by Auro – a German brand who use isothiazolinone preservatives in a few of their products, but several others of which are free from them.
Although most domestic paints and varnishes contain methylisothiazolinone and/or other related preservatives, typically benzisothiazolinone, there is no requirement to declare this content on the container (unless above 100 parts per million, in the EU), making life hazardous for those with MI allergy. Airborne exposure is particularly risky when painting, but the effect can linger for up to six weeks, triggering rashes and respiratory problems as the isothiazolinone allergens vaporise into the local atmosphere.
Usefully, Auro declare the composition of their products on their Technical Data Sheets, made available on their German website. For example, Auro 328 is listed as only containing water, calcium hydroxide, titanium dioxide, mineral fillers and cellulose.
But others contain isothiazolinone preservatives. For example, Auro 320. Noticeable here is that the preservatives are listed as “thiazoles” – a word which may not be a recognisable warning sign to all. I had assumed that the ‘iso’ string of letters would be ever-present in any word synonymous with the isothiazolinone preservatives, other than brand names, but this is apparently not the case. In fact, Edward Bulmer Paints – another brand who use the preservatives in a few of their products, but have a wide selection of safe options as well – refer to them as “thiazoline compounds” too.
The various names under which isothiazolinone preservatives can appear are given in our article, Other Names for MI, but it is worth bearing in mind that the tell-tale string of letters you need to look out for in any chemical name is, in fact, just “thiazol” – although in practice, they will usually appear in a more expansive form!
There is another useful article on the AIMB Facebook group – Finding Paint Without MI or BIT – which not only lists other possible options, but also explains that a solution of 10% sodium bisulphite (not bisulphate) can sometimes be used successfully to ‘neutralise’ walls painted with an isothiazolinone-containing paint, to lessen or stop the ‘off gassing’ effect. One commenter there, incidentally, also had success with the Auro 328, mentioned above.
A painter and decorator with MI allergy, who left a comment in an article on MI in Paint by cosmetic scientist Colin Sanders, experimented with mixing bisulphite in with the paint, but sadly without success. The principle is an interesting one, though, and I wonder whether a solution along similar lines, with a different ‘neutralising’ agent, might be possible.
Finally, if you’re looking for kids paints / school art supplies, see this article by Jill (Snarky Dabbler).
And if you’re looking for safe face paints, for adults as well as kids, see this article on our site.