Workplace drug and alcohol testing can provide a measurable return on investment and a proven improvement to safety, especially when it comes to workers’ compensation claims. An employee’s substance abuse should not make an employer liable in the event of an accident. A rebuttable presumption is an assumption that something is true unless someone comes forth to contest it and prove otherwise. State laws vary when it comes to a rebuttable presumption. Employers can prepare a complete defense by creating a written drug-free workplace policy and enforcing it; implementing supervisor training and employee education programs; conducting drug testing as soon after the accident as possible and follow-up drug testing with an investigation, and questioning co-workers and supervisors.