The benefits of drug testing are numerous, from making companies and communities safer and healthier, to savings in health care costs, lower absenteeism and employer liability claims, and a more productive workforce with an increase in performance and higher quality work. Those who plan to drug test should have a clear, written policy regarding substance abuse and training for supervisors. It is important for employers to understand that substances vary in the length of times that they remain in a person’s system, from 1.5 hours for an ounce of alcohol to 1 week for PCP. Other substances that are commonly tested for include amphetamines, THC, cocaine and opiates.