Some jobs involve exposure to very hazardous materials, such as lead and other toxic materials. ...

Some jobs involve exposure to very hazardous materials, such as lead and other toxic
  materials. Could a company appropriately prohibit women from holding such jobs, on the
  grounds that the toxic environment might harm fetuses of pregnant women? Johnson Controls
  manufactures batteries, using lead as a primary ingredient. Known harm caused by exposure to
  lead includes harm to the fetus carried a female employee. Johnson Control began hiring
  women for work in its factories in 1977. After several workers became pregnant and had lead
  levels in their blood in excess of recommended levels, the company adopted a new policy
  prohibiting any women who were pregnant or of child-bearing age from working in areas of the
  factory where they might be exposed to lead. The U.S. Supreme Court, in 1991, struck down
  the restriction as a violation of the Pregnancy Discrimination Act, noting that men could also
  suffer from exposure to lead but were not barred from these jobs.