Research Paper Number



Odelia R. Bay

View the research paper on SSRN here.

Document Type


Publication Date



Multiple chemical sensitivities, MCS, invisible disability, disability, accommodation, discrimination, human rights law, Americans with Disabilities Act, Canada, United States


People with invisible illnesses are challenged both by their impairments and the additional hurdles they face when it comes to being believed by others. This presents particular difficulties when seeking to convince those with the authority to make legal findings of discrimination or entitlement to accommodation. By focusing on the historically contested diagnosis of multiple chemical sensitivities (“MCS”), this paper examines the outer limits of how disability is defined and the legal rights given to people whose claims are viewed as suspect. Specifically, comparison is made between MCS employment cases in the United States and Canada.

In both jurisdictions, plaintiffs face challenges related to findings of credibility, a prioritization of scientific evidence over experiential knowledge, and efforts to rule out accommodation measures by exaggerating disabilities. In the end result, people with MCS are statistically more likely to succeed in Canada; but, the tide is turning. Twenty-five years after the passage of the Americans with Disabilities Act, American courts are becoming more receptive to a plaintiff’s lived experience of MCS as a disability. At the same time, Canadian tribunals are increasingly looking to scientific and medical validation at the expense of a claimant’s lived reality.

As new diseases emerge, the law in both countries must progress to allow medical and scientific evidence to follow, not lead, experiential accounts of disablement in the workplace. Otherwise, the result will be to create a class of people with invisible disabilities who have no hope of being rendered visible by our courts and tribunals.