NFPA - National Fire Prevention Association®

NFPA - The National Fire Protection Association offers free online access to the fire codes.  The sign-up is free.

NFPA 704 - Standard System for the Identification of the Hazards of Materials for Emergency Response. This is commonly referred to as the fire diamond, and indicates the severity of the hazards for health (blue), flammability (red), reactivity (yellow), and other (white).