Pennsylvania Department of Labor and Industry tells us that "Pennsylvania employers are required to post certain notices in their worksites so employees have access to and information about applicable labor laws. These posters can be downloaded for free from the links below. Each poster link identifies the content of the poster, which employers are required to post it and contact information should you require additional information.
All notices must be posted in a conspicuous place so that they can be seen and read by employees. Failure to post notices can result in stiff penalties and possible fines. In addition to the notices listed below, all government agencies and private employers with government contracts over $25,000 are required to publish and post an anti-drug policy statement in accordance with the Drug-Free Workplace Act of 1998."