Is there a restriction, either in Labor Law or OSHA, that limits the number of hours an employee may work? An hourly employee here logs many 18-hr days, much of which is worked alone. We are certain there is limited productivity, perhaps sleeping. Nonetheless, as long as he is clocked in, and we have no evidence of misbehavior, we are paying lots of overtime. As mgt, I realize we can impose a "maximum hours worked" policy...I just wondered if there is a law in place that we could reference as well. There is a safety issue, as this employee works with dangerous machinery.
No, there are no laws in Texas (or most other states) limiting the number of hours an employee can be required to work. There are a few industry specific exceptions, or, as Wayne will certainly tell you if I don't, there might be a restriction in a CBA. But I suspect if such a restriction existed, you wouldn't be asking the question.
Maine and California are the only states that have put any kind of legal restrictions on hours worked, and even they have not put down any daily limits; only bi-weekly (Maine) and weekly (California)
However, I applaud your concern for your employee and encourage you to lay down the law to him. Safety is a very valid reason for not allowing employees to work past the point of real fatigue. It's possible that there might be an OSHA restriction depending on what the machinery is, but you didn't give us enough information to say for certain. The OSHA website is www.osha.gov.