THE CHEMICAL INVASION

For many people, compounds in the air and in everyday objects can wage an assault on the body. Here's what we know about chemical intolerance, a.k.a. multiple chemical sensitivity (MCS).

- MERYL DAVIDS LANDAU

A DECADE AGO, Corinne Segura, of Victoria, Canada, was an active 29-year-old who enjoyed salsa dancing and liked to cycle. But after exposure to mold in her rental home, she began having strange symptoms: Whenever Corinne was around certain very common chemicals-air fresheners, household pesticides, new carpet in a doctor's office, gas station pumps, even essential oil diffuser she became dizzy, disoriented, and exhausted, and her throat would swell. The symptoms became so debilitating, she eventually had to quit her job as a grant writer and move.

Doctors prescribed antihistamines and an asthma inhaler, but the only thing that helped was avoidance. “The more I removed chemicals from my space, the simpler it was to tell which products bothered me," Corinne says. After several years of this and taking supplements prescribed by a naturopath, Corinne has greatly improved. But her recovery hasn't been a straight line: When smoke from the California fires of 2020 wafted her way, her sensitivities revved back up. Recently, she says, she was stuck in fumy traffic and had to spend a day recovering in bed.