You can help prevent illness and injury by reading the warning label for each hazardous substance you use. If you have any questions after reading the warning label, check the SDS. The SDS is a detailed source of information for the hazardous substance you are using. The image is an example of a National Fire Protection Association (NFPA) label you might find on a container.
NFPA 704 warning labels
You may see a warning label on a container or box of containers, such as a case of chemical jugs. These labels provide the most important information you need to know about the substance you are handling.
The number system is based on the NFPA 704 rating:
-
Hazard ratings range from 0 to 4, with 4 being the most hazardous. These are used for three categories: health (blue), flammability (red), and instability (yellow). For example, if the substance has a low risk for flammability, a “1” may appear in the flammability section.
-
The Special Hazard category shows other important hazards to be aware of. These include OX (oxidizers), W (water reactives), and SA (simple asphyxiant gases, such as nitrogen or helium).
Online Medical Reviewer: Eric Perez MD
Online Medical Reviewer: Marianne Fraser MSN RN
Online Medical Reviewer: Raymond Kent Turley BSN MSN RN
Date Last Reviewed: 12/01/2022
© 2000-2025 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
Find the right provider to meet your needs
From primary care to specialty services and more.
Find a Doctor
Call for an Appointment
Offering personalized care at more than 20 clinics across three cities and two states.
Call NowRelated Articles
Reducing Risk of Work-related MSDs: Part of Your Health and Safety Program
Reducing job-related injuries is part of every health and safety program. By taking responsibility for your health and well-being, you help prevent future injury and control any present symptoms.
Understanding Container Labels and Hazardous Chemicals
You can help prevent illness and injury by reading the container label for each hazardous substance you use.
Ergonomics and Musculoskeletal Disorders: Quiz
Take this short quiz to find out how much you know about ergonomics and musculoskeletal disorders (MSDs). Select the best answer for each question. Answers are at the bottom of the page.
HazCom: Radiation
Protect yourself from accidental radiation exposure with these precautions.