Is this a sin?

[Clare~Therese]

If, at work, you disobey some State regulation(s) because your supervisor(s) have told you to do so, is it a sin?

For example, if you work in the kitchen at a restaurant as a dishwasher, and State regulations forbid drying dishes with towels (because it's considered contamination), but you dry dishes with a towel anyway because that's what your supervisor tells you to do. 

[CatherineM]

I'd ask the supervisor's boss if it's okay. Then again, I'm not the one who might get fired. If you're being forced to do it to keep your job, try to use as clean a towel as possible. It being a sin or not is a very gray area. If you can easily get another job, that would make a difference. If you can't and you're supporting a family, that would make a difference. I'd suggest talking over the specifics of your situation with your confessor.