Summary of Law(s) and Regulation(s):
Benefits may be reduced 50% if the employee fails to obey employer’s drug-free workplace policy or uses alcohol or nonprescribed controlled drugs in the workplace. If the proximate cause of the injury, then benefits shall be forfeited. The voluntary use of alcohol creates a rebuttable presumption as the proximate cause of the injury. Refusal to test shall result in the forfeiture of benefits if the employer had sufficient cause to suspect use of alcohol or a nonprescribed controlled substance or if the employer's policy clearly authorizes post-injury testing.
Mo. Rev. Stat. § 287.120 (6)(Supp. 2006)
http://www.moga.mo.gov/statutes/c200-299/2870000120.htm