"The allowance of employer drug testing is founded in the idea that employers have a legitimate interest in workplace safety.22 The employment relationship comes from the common law doctrine of 'employment at will' — that both parties to the employment contract can terminate the contract for any reason, at any time, unless otherwise specified in the contract."


Smith, Melissa K., "Drug Testing: A Solution Looking for a Problem," Michigan League FOR Human Services (Lansing, MI: March 2012), p. 5.