Final answer:
Horizontal standards are characterized by general workplace guidelines that apply across multiple industries to protect workers from a variety of hazards as set forth by OSHA.
Step-by-step explanation:
What characterizes horizontal standards? Among the options provided, the correct characterization would be Option 3: General workplace guidelines. Horizontal standards are not industry-specific but instead apply across various industries, providing a set of uniform guidelines that are applicable to broad categories of work environments and practices. These are designed to protect workers from a wide range of serious hazards such as falls, cave-ins, infectious diseases, exposure to harmful chemicals, and safety around dangerous machinery. The Occupational Safety and Health Administration (OSHA) sets these standards to promote health and safety across different sectors.