Wired: The Hairy Problem With Drug Testing by Ellen Airhart:
Boston police officers whose hair tests positive for drugs usually have two options: admit their substance abuse problems and agree to a stint in rehabilitation, or relinquish their position. But Hogan, who finished her police training prior to 2005, says that she has never used cocaine; when she sent her hair to a private company for more testing, it came back negative. Now, she and nine other black police officers are suing the city of Boston, saying that the practice of testing hair for drugs is discriminatory. Because of the chemistry behind the test, they say, it unfairly targets dark hair. The bench trial for the case began on March 12, and may have long-lasting consequences for the future of drug testing.