When you come into work, you are declaring that you are "fit for duty." Whether you are coming in for your regular work day or you accept a call out. Many of us are subject to random drug and alcohol testing and therefore have some knowledge of what is expected of us on this subject. However, those who are not on a testing list have the same required of them as those of us who are being tested.
If you accept a call to go work storm away from home, and you are released to go to your room for rest after working, the company expects you to be fit for duty. Fit for duty when you are to be back for work. Fit for duty if they contact you to come in off rest because you are needed.
Should you have chosen to take alcohol to your room to drink, you may very well be putting yourself in a position of not being fit for duty. If you are home mowing the lawn on a hot summer day and you have had a couple of beers, and the company calls you to come to work, keep mowing the lawn.
Say you travel to a state where marijuana is legally sold and consumed. You decide to partake, then you will not be considered fit for duty to return to work until the drug is completely out of your system.
The following was taken from a company "Code of Conduct." Employees are prohibited from engaging in the use, sale, purchase, transfer, possession or presence in one's system of any alcohol or illegal drug or controlled substance (except medically prescribed drugs) while engaging in company business or while on company property. The company will comply with the Department of Transportation and any other applicable regulatory requirements for drug and alcohol testing. If you are taking a prescribed medication that might affect your safety or efficiency, you should inform your supervisor before you begin work.
Please make safe decisions.