will show as opiate usage.

I have had to take a drug test for one job application. I did pass.

the problem I see is that some illegals, that are considered 'less harmful' such as marijuana, stay in your system for weeks/months after stopping usage. readily available evidence from urine, blood or hair samples.

cocaine leaves the system within hours. also alcohol. prescription drugs might be detected but that does not indicate if they are being abused. add 'doctor shopping', more than one pharmacy and it is not that hard to get multiple legal prescriptions. available to sell or abuse.