Every employee brings his own idiosyncrasies to his employment. This includes pre-existing weaknesses, hypersensitivities, and other susceptibilities that could impact the employee’s health. The minority rule in workers’ compensation coverage is that there is no recovery for an occupational disease where a pre-existing condition, such as asthma, contributed to the resulting disease. The minority states consider the disease to be the result of the employee’s own innate susceptibility rather than to the peculiar conditions of his employment.
The majority of states find that it is immaterial that the employee suffers from an allergy or other pre-existing weakness. These jurisdictions focus on whether the employee’s disability was, in fact, caused by the singular conditions of his employment. The amount of exposure to the disease-causing agent is of no consequence as long as it was in a sufficient amount to cause the disease in concert with the employee’s individual susceptibility.
Where there is more than one reason for the employee’s disease, i.e. the conditions of his employment and a personal aspect (ex. an asbestos worker who smokes a pack of cigarettes a day), courts have varied in their compensation results. Generally, recovery turns on proof of occupational cause. Claimants must prove, through medical evidence, that the employment condition caused or contributed to the illness in light of evidence of the claimant’s personal element.