Lynn said that she grew up in a home were a person was expected to be strong and take illnesses that came along. Though they worked together on much of the remodeling, Lynn, who didn't work outside the home, was exposed to the fumes all day. That's one reason, they believe, John was unaffected. Also, immune systems and tolerance levels vary with each individual. People with MCS often use an analogy of a rain barrel.
Toxins build up in the body like rainwater in the barrel.
Depending on the size of the drain hole at the bottom, a barrel empties itself faster or slower than others, just as some people's bodies can purge toxins faster than others. For most people, the barrel never fills completely. But for those who suffer from full-blown MCS, their exposure to toxins has filled their systems to their limit. Their deluged immune systems become overwhelmed. But chemical sensitivity is still treated with curiosity and skepticism.