Why Surrogates Must Avoid Secondhand Smoke and Marijuana Exposure Ivy Surrogacy Ivy Surrogacy What Can Cause a False Positive Drug Test Can Secondhand Marijuana Smoke Cause a Failed DOT Drug Test? The Science and the Defense That Won't Work What Can Cause a Positive THC Urine Test: Medications and Food Claritas Genomics Focused on the Facts: Secondhand Marijuana Smoke American Nonsmokers' Rights Foundation no smoke.org