OIT Air Purifiers – 3M Recall

November 27, 2020 2 min read

OIT Air Purifiers – 3M Recall


OIT air purifiers (OIT stands for octylisothiazolinone - see footnote for a detailed description) have been widely used in South Korea and this had led to major recalls, the reason being that OIT is a chemical that has been widely categorised as unsafe[1]. You might expect an air purifier to improve your health, certainly not to damage it by emitting toxic chemicals; however, recently a local broadcast in South Korea noted that tests by the Environment Ministry showed that emissions of a potentially harmful substance, OIT, had been detected in no less than 51 air purifiers! These are produced by seven companies and 33 vehicle air conditioners produced by six companies. The filters of these products all came from either ‘3M Korea’ (a subsidiary of the American multinational) or ‘CNTUS Sungjin’. Although the Ministry initially issued a public health warning, it later countered that by claiming that the levels of OIT detected may not actually pose a health hazard or contribute air pollution.

Five years previously, the use of domestic humidifiers manufactured by 3M was linked to both lung damage and the death of four pregnant women in South Korea. Further investigation suggested there have been as many as 147 deaths connected to this exposure.

How widespread is the problem of OIT air purifiers?

Tens of thousands of customers in Korea have been exposed, this has led companies to recall the OIT air purifiers and offering to replace them with filters that do not contain OIT for free. It seems that South Korea is the only country where the OIT-containing filters have been supplied, leading for calls for the strengthening of consumer protection there; as there have been other instances where the products of multinational companies have, at least potentially, posed a health hazard to the population.

What health problems can OIT cause?

OIT is a sensitizer and there have been a number of case reports of contact allergy from exposure to OIT. A study from Odense University Hospital looked at OIT patch test results in the Allergen Bank and found that 20 out of 648 patients tested positive. Of these, 90% had been exposed in occupational settings, with most being painters. OIT can be toxic by both skin contact and inhalation. It is chemically related to other isothiazolinones in industrial use, all of which can be sensitizers.

What has 3M done about the problem?

The company apologised – although many critics felt they left it too late – while still insisting that levels of OIT emitted by the filters were not harmful. They have begun a recall of the filters and stopped their manufacture.


Further information

1 Mose AP, Frost S et al (2013). Allergic contact dermatitis from octylisothiazolinone. Contact Dermatitis69 (1) 49-52

[1] OIT is octylisothiazolinone – a chemical used as a biocide and preservative in a wide range of industrial products, including polishes, paints, cleaners, detergents and metalworking fluids. It has been in use for around 30 years. It is listed as an antimicrobial agent on the European Commission database but is not allowed in cosmetic products in the EU. In the USA and Canada OIT is not even listed as a safe preservative.


Leave a comment

Comments will be approved before showing up.

Also in News



Coronavirus Air Purifiers: Do They Help?

May 12, 2021 5 min read

The average domestic air purifier should not be considered for the removal of airborne coronavirus, especially those air purifiers which do not clearly state the air purifier’s filtration efficiency. Instead, we will assess what you will need to be aware of when searching for the air purifier to combat the spread of coronavirus.
Information About Hay Fever in March


Information About Hay Fever in March

March 08, 2021 3 min read

Hay fever in march tends brings on sneezing, a runny and/or blocked nose and red, streaming eyes. If you experience these symptoms, then it is likely that you have seasonal allergic rhinitis - also known as hay fever. Having Hay Fever means that you are likely allergic to pollen and, at this time of the year, it is most likely that tree pollen is the underlying cause.

Vax Air Purifier Review


Vax Air Purifier Review

February 09, 2021 6 min read

The VAX AP03 air purifier is a basic mid-range air purifier with basic features. The timer is simple, but the filter life indicator seems flawed. It is hard to imagine the odour/carbon filter to be anything else then ineffective in capturing and retaining gases and chemicals.

Be part of our regular news updates