The 9th Circuit has ruled that an employee can't be kept from a particular job just because the work environment may aggravate an existing disability.  In the case of Echazabal v. Chevron, USA, the court ruled that an employer may not use the "direct threat" defense to a claim under the Americans with Disabilities Act where the threat posed by the job would affect only the disabled employee. The ADA allows an employer to refuse to assign an otherwise qualified individual to a job that would create a "direct threat" to the health or safety of other employees.  The court in this case held that Congress did not intend this defense to protect disabled workers from themselves, but rather was intended to give a disabled employee the right to choose to work in a potentially hazardous job, so long as he or she can perform its essential functions.  "Conscious of the the history of paternalistic rules that have often excluded disabled individuals from the workplace, Congress concluded that disabled persons should be afforded the opportunity to decide for themselves what risks to undertake." In this case, Echazabal had a liver condition that Chevron believed would be made worse by exposure to certain chemicals present at Chevron's facility.  Chevron refused to let him work there, and he sued for violation of the ADA.  The lower court initially dismissed the claim against Chevron, but the 9th Circuit sent the case back to the trial court for more proceedings.  The ruling was filed in final form on September 26, 2000.