Well before the early 1500s, when Sir Thomas More first coined the term “Utopia,” people have been thinking about how to design their ideal community. Maybe it’s one that doesn’t use money, or one that drops traditional family structures and raises children collectively.

For a community of people on the outskirts of the small Arizona town of Snowflake, “utopia” is just a place where they won’t be physically sick. That’s because everyone in this community is suffering from Multiple Chemical Sensitivity or MCS.

People with MCS suffer from migraines, muscle pain, rashes, nausea, fatigue, and other debilitating symptoms they believe to be caused by low-level exposure to chemicals such as laundry detergent, perfume, and car exhaust.

Most scientific studies have not shown a strong connection between chemical exposure and symptoms, and the American Medical Association does not recognize the illness as an organic, chemical-caused disease. But doctors still disagree about what exactly causes it — whether symptoms are physiological, psychological, or both. There is a subset of doctors who believe in MCS and treat it, but most mainstream physicians avoid the diagnosis and may recommend therapy to treat the symptoms. A lot of people with the illness take matters into their own hands, designing their diets, habits, and environments make themselves feel better.

The people in this Arizona community might be the closest thing there is to an “MCS think tank” and they’ve developed building techniques to help manage their sensitivities. That means using “safe” materials like ceramic tiles or concrete floors rather than carpeting, which traps chemical odors. Many leave their windows wide open, even in the winter, to keep air flowing through their houses. Some people with MCS also experience sensitivity to electricity, so some houses forgo electricity, or have it routed through a single room which can be completely shut off from the rest of the house.

There are about three dozen households in the Snowflake community, but the waiting list is long. Susan Molloy, who keeps track of the housing, gets calls every week from “runners,” who are moving from place to place, looking for somewhere that won’t aggravate their sensitivities.

Snowflake isn’t the only community of its kind, but it’s one of the largest and most established. Some local businesses in the larger town of Snowflake have even begun to adapt to the MCS community, at least a little bit. Sierra Dental has tailored their practice to make it friendly to their MCS patients. There’s a real estate agent who helps people find MCS-friendly properties. There’s also an organic food store where the owner will shop for people with MCS and leave the groceries outside for them to pick up, so they don’t have to come into the store, which smells like incense.

This MCS utopia is a complicated place. Some doctors would argue it isolates people, pushing them deeper into their illness. But Susan Molloy claims that Snowflake is a necessary refuge, and she guards the place fiercely. “All it takes is one family building a gas station out there on the road, and a lot of us would have to move.”