I think the expunging of records is a poor solution, and I support a potential employer's right to test for drugs and to learn of criminal convictions. I judge harshly those employers with attitudes like yours, who automatically write-off those who were caught making stupid mistakes in their youths or early adulthood as bad risks and of poor character. In many cases the opposite is true -- they are of unusually strong character and have considerly less risk of EVER surrendering again to temptation.
I would also be leery of putting very much confidence into such judgemental employers or their operations because when it comes to cocaine abuse in particular, they have no idea what they're tangling with. The employer smart enought to see the positive side of the redeemed cocaine addict, will hire a better worker who will not only give the employer considerable loyalty because of the trust shown, but because the new employee has survived and learned to loathe the addiction will be 100 times more likely to spot it in the company and be devoted to halting it -- and it's common, believe me. You yourself probably are acquainted with many successful professionals who are cocaine users, but you don't know it and never will unless they get caught. Like as not you might even have hired one or two. The reason I know this is because ... I've been there.
I KNOW FOR SURE that the person who used to be addicted to cocaine, alcohol, heroin, you name it, and who has turned his or her life around by overcoming the addiction, has a demonstrably strong character. This is someone who has met and conquered personal challenges that most people never know, and that most people when they do know them, don't have the strength, the discipline, the insight, the humility, to resolve them. George W. Bush was already my favorite, but when I learned that he was a reformed alcoholic, my respect for him soared because I know very well what that entails. It made him BETTER QUALIFIED, in my book.
Are you in the Fellowship?