Which of the following is not considered a primary source of technical information on chemical hazards?

The Association of American Railroads is not considered a primary source of technical information on chemical hazards because its main focus is on the transportation industry and the interests associated with railroads. While they may provide some information related to chemical handling in the context of transport, their expertise does not primarily center on the chemical hazards themselves or the technical specifications involved in handling hazardous materials.

In contrast, organizations like the National Fire Protection Association, the Manufacturing Chemists Association, and the National Agricultural Chemists Association specialize in aspects related to chemical safety, regulation, and information dissemination regarding chemical hazards. These associations provide essential resources and guidelines for identifying, evaluating, and mitigating risks associated with chemical exposure, making them recognized authorities in the field of chemical safety.