Methylisothiazolinone (MI) is used as a preservative in consumer products like cosmetics and household cleaning products to extend their shelf life. It is sometimes used in paints. Though not thought to be inherently toxic, MI is a relatively common allergen and has been identified as a possible neurotoxin.
In February 2019, AURO and Farrow and Ball were both phasing out the use of MI. No other brands had information specifically on MI.
3) Volatile Organic Compounds
Volatile organic compounds (VOCs) are solvents added to paints for fluidity and to make them dry quickly. They can be can be naturally occurring (such as ethanol) or can be synthesised chemically.
VOCs are mixtures of chemicals that can easily change state into gases. In the presence of sunlight, VOCs can react with oxides, which are naturally present in the atmosphere, and create greenhouse gases (which contribute to global warming) and other small particles that cause smog.
This process, known as ‘off gassing’, can occur long after the paint has dried, creating an ‘invisible paint pollution effect’ long into the future.
The World Health Organisation has found that, when painting, the levels of VOCs given off can be as much as 1000 times higher than found outdoors.
In terms of health, VOCs are not acutely toxic but can lead to long-term adverse health impacts.
VOCs are what cause the headaches and nose or eye irritation that you’ve likely experienced whilst painting. More regular and prolonged use of paints with medium to high VOC levels can lead to more serious issues such as damage to the lungs. Paints with high VOC levels can be particularly hazardous for people with respiratory problems like asthma, as well as for children and the elderly.
In 2010 an EU directive came into force which heavily restricted the solvent (or VOC) content in paints.