Depending on the industry in which the employer operates, there may be industry specific provisions that you will want to include in the handbook. For instance, I represented a towing company once and it was imperative that we include a policy that employee drivers notify the company when they incur traffic violations or are in an accident, whether on the clock or not. This was important to be compliant with US DOT and PA DOT regulations. In addition, when the client came to me, they had no drug testing policy which we also determined would be critical to have.
Manufacturing facilities (as well as other business locales) are subject to Occupational Safety and Health Administration (OSHA) requirements. Placing safety policies in the employee handbook is important. As a matter of fact, OSHA requires that employers document their cooperation with the rules in the employee handbook. A reporting procedure should also be in the handbook, to cover workplace dangers, injuries, and accidents.