An Epidemic of Contact Dermatitis 

A powerful industrial preservative found in baby wipes, band-aids, hand sanitizers, sunscreens, lotions, glue and thousands of other products is causing what dermatologists are calling “an epidemic of contact dermatitis.”

bandaid reaction

Reaction to MI from a band-aid

About Methylisothiazolinone (MI, MIT)

MIT is a powerful synthetic biocide and preservative within the group of isothiazolinones, originally used in industrial applications. MIT and related biocides Chloromethylisothiazolinone (CMIT), Benzisothiazolinone (BIT), Octylisothiazolinone (OIT), Dichloroctylisothiazolinone (DCOIT) are used for controlling microbial growth in water-containing solutions and in a variety of industrial water treatment applications. It is also used in thousands of personal care products, adhesives, paints and other items that require a liquid biocide preservative. MIT’s use has even expanded into mouthwash, as one woman sensitive to MI found out after her serious reaction.

skin issues

Sampling of products that contain MIT

MIT products

Risks to the Fetus and Development

Some companies turned to MI to avoid parabens, but, as Dr. Lindsey Bordone a dermatologist at Columbia University Medical Center says, “There’s no perfect preservative, and I think that’s part of the issue.”

Research indicates serious risks from this biocide.

  • MIT was named the 2013 Contact Allergen of the Year by the American Contact Dermatitis Society.
  • Multiple studies show links to neurotoxicity in mammals. A study, from the University of Pittsburgh found that a short, acute exposure to MIT “is highly toxic to cultured neurons which may have potentially damaging consequences to a developing nervous system.” Dr. Aizenman, senior author and professor of neurobiology at the University of Pittsburgh School of Medicine said, “I would be particularly concerned about occupational exposure in pregnant women and the possibility of risk to the fetus.”
  • In vitro studies have shown that MIT and CMIT are profoundly cytotoxic to different types of cell lines.
  • In 2006, a study indicated that longer term, low concentrations of the biocide result in abnormal neurological function such as “visual processing deficits and increased seizure susceptibility.”
  • In 2014, Baylor College of Medicine published a paper about the rising rates of contact dermatitis with MIT as a possible cause. Of special note were their findings that products marketed for children were labeled as “gentle,” “sensitive,” “organic,” or “hypoallergenic” emphasizing that these products are often the ones containing MIT.

skin issues

Findings in Patient Studies

A 5 year multicenter study conducted on children with eczema aged 0-15 years, found that 46.8% had at least one positive reaction in the patch test. The most common allergens were nickel sulfate, MCI/MIT and fragrance mix. What compound is allowable in fragrance?  Yes, MIT.

In 2015-16 in Australia and New Zealand, patch testing up to 20-25% of all patients tested to MI have been positive. Dr. Elias Aizenman, Ph.D., professor of neurobiology, states, “This chemical is being used more and more extensively, yet there have been no neurotoxicity studies in humans to indicate what kind and at what level exposure is safe. I realize its a big leap to suggest there may be a parallel between environmental exposure and the noticeably higher rates of diagnosed childhood developmental disabilities, but I would caution that based on our data, there very well could be neurodevelopmental consequences from MIT.”

skin issuesA European committee who recommends standards on prevention, (StanDerm), issued this statement: “It is also important to note that once sensitised (by whichever route or product type), even airborne exposure to vapours of drying paint containing MI can lead to severe allergic contact dermatitis of exposed skin (mostly face, hands and arms) as proven by multiple case reports and daily clinical experience.

What to Look For On A Label

These are many ways the biocide can be listed such as a chemical name or a brand name.  It can also “hide” in fragrance as MCI.  Here are some of the most common ways it appears on labels:

Methylisothiazolinone (MI/MIT): 2-methyl-4-isothiazoline-3-one, Kathon. Neolone 950 preservative, MI, OriStar MIT and Microcare MT. Methylchloroisothiazolinone (CMIT): 5-Chloro-2-methyl-4-isothiazolin-3-one and MCI. Methylisothiazolinone Free is a resource for those with allergies to MI and other preservatives that has a comprehensive list.

baby wipes

EU and Canada Taking A Stand

Due to the number of skin reactions from this preservative, the European Society of Contact Dermatitis recommended a ban. In April of this year, the European Commission took action and voted to ban the use of MIT in cosmetic leave-on products. (including hair-leave-on products, cosmetic wet wipes and baby wipes containing MI).

The restriction of MIT in rinse-off products is now being proposed bringing the allowable amount down from 100ppm to 15ppm and requiring a warning label: “Contains Methylisothiazolinone.”

Canada is informing Canadians of the risks of MI/MCI in leave-on cosmetics, non-prescription and natural health products: Adverse reactions can include rashes, itching, dry, cracked or scaly skin and blisters. Health Canada reports that “these symptoms may occur each time someone uses a product containing MI/MCI and may become more severe with repeated use.”  MI/MCI is also in rinse-off products.

Health Canada has amended their Cosmetic Ingredient Hotlist with the following regulations:

  • After June 14, 2016, all products intended for use by children under the age of three that contain MI/MCI should no longer be available for purchase.
  • All other leave-on products containing MI/MCI should no longer be available for purchase after December 31, 2016.
  • Health Canada will monitor the marketplace for information about health or safety concerns involving products with MI/MCI. The Department will follow up with companies if their products are related to an incident and will take compliance and enforcement actions where appropriate. If you experience an adverse reaction related to a cosmetic product, or a non-prescription or natural health product, report it to Health Canada as well as the establishment where the product or service was purchased.

 What Needs to be Done

  • MIT should be added to Proposition 65 list based on its neurotoxicity.
  • MIT should be added to the California Biomonitoring Program.
  • MIT should be clearly labeled on all consumer products and any products where workers could come in contact with it.
  • MIT should be added as a chemical of concern to the state’s Occupational Health and Safety Program.
  • Exposure to MIT-caused eczema is at epidemic proportions and outreach should be done to the public health community regarding the proper treatment and preventative steps for this outbreak
  • MIT is in art supplies including paints, glues, and many other products used in schools; OEEHA should add MIT to its Arts and Crafts Hazard List.


Methylisothiazolinone Victims Facebook Group
Methylisothiazolinone Free Information Site
Household Products Database, U.S. Department of Health & Human Services database of products that contain Methylisothiazolinone

About the Authors

jane williamsJane Williams serves as the Executive Director of California Communities Against Toxics (CCAT). A network of local environmental justice groups in California, CCAT works to protect communities from industrial pollutants. Jane carries on in the tradition of her mother, environmentalist Norma Stormy Gail Williams, working to protect the health of people and the environment as a common cause. Her mother, Norma, had launched a campaign that sought to identify toxins causing a brain cancer cluster among children in her small town of Rosamond, California.

Jane has organized dozens of communities to successfully fight the building of facilities that would pollute their environment such as incinerators, landfills, nuclear waste dumps, and industrial plants. Jane has also served on a number of federal and state advisory committees that study the effects of toxic chemicals on children and public health. 

robina suwol

Robina Suwol is the founder and executive director of California Safe Schools (CSS)children’s environmental health and justice coalition founded in 1998. CSS achieved national and international prominence by spearheading the Los Angeles Unified Integrated Pest Management (IPM) Policy, the most stringent pesticide policy in the nation for K-12 public schools – the first to embrace the “Precautionary Principle” and “Right to Know” and then the passage of California’s Healthy Schools Act. Today the LA Unified IPM policy serves as an international model for school districts and communities.

On October 6, 2005, Governor Schwarzenegger signed AB 405 (Montanez) sponsored by California Safe Schools. The bill bans experimental pesticides whose health effects are unknown, from California K-12 public schools. CSS works closely with diverse communities & regulatory agencies on environmental health and toxics in air, water and soil.

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