Flammable and combustible liquids have the potential to harm employees in the workplace, typically due to the fire hazard they pose. Because of this, the Occupational Safety and Health Administration (OSHA) maintains general requirements for the handling, storage, and use of liquids with a flash point below 200°F (“flammable liquids”) in containers, portable tanks, and tank systems. [29 CFR 1910.106]
The standard addresses the requirements for:
- Design, construction, and capacity of flammable or combustible liquid storage units;
- Ventilation; and
OSHA recently adopted the Globally Harmonized System for Classifying and Labeling of Chemicals (GHS). While the bulk of the adopted standards relate to OSHA’s Hazard Communication (HazCom) Standard, GHS also affects several other OSHA regulations, including the Flammable Liquid Standard.
The main modification to the Flammable Liquid Standard is how flammables are classified.
“Old” Flammable and Combustible Classification
Under OSHA’s “old” standard (pre-GHS), liquids were defined as either “flammable” or “combustible” and divided into three “classes.”
Flammables were considered the more dangerous liquids under the pre-GHS standard. These liquids have lower flash points, meaning that they ignite more easily. Flammable liquids were defined as any liquid with a flash point below 100°F and were considered to be “Class 1 liquids.” A flammable could be Class 1A, 1B, or 1C, with 1A being the most dangerous.
OSHA defined combustibles as liquids with a flash point ranging from 100°F to 200°F. These liquids were divided into Class 2 and Class 3 liquids. Class 2 combustibles were more flammable than Class 3, due to their lower flash points.
The goal of OSHA’s pre-GHS standard was to ensure that the liquids that posed the greatest hazard were regulated more stringently than less hazardous liquids.
“New” Flammable Classification
Now that OSHA has adopted the GHS, the Class 1, 2, and 3 distinctions no longer exist. “Flammable liquids” are now divided into four “categories.” Despite the change, OSHA’s goal remains the same: to reserve the most stringent regulations for the most dangerous liquids. In fact, many of the old classes have approximately the same cut-off levels for flash point and boiling point as the new categories.
Below are the four categories of flammable liquids (with their approximate “old class” as comparison):
- Category 1 – liquids having flash points below 73.4°F (23°C) and a boiling point at or below 95°F (35°C) (~IA);
- Category 2 – liquids having flash points below 73.4°F (23°C) and a boiling point above 95°F (35°C) (~IB);
- Category 3 – liquids having flash points at or above 73.4°F (23°C) and at or below 140°F (60°C) (~IC and II); and
- Category 4 – liquids having flash points above 140°F (60°C) and at or below 199.4°F (93°C) (~III).
[29 CFR 1910.106(a)(19)]
To find all of the requirements under OSHA’s Flammable Liquid Standard, see 29 CFR 1910.106.
OSHA Requires Employee HazCom Training
Under OSHA’s Hazard Communication (HazCom) Standard, all employers must train employees on the hazards present in their workplace. The Hazard Communication Online Course
has been updated to include important information about OSHA’s adoption of the Globally Harmonized System (GHS) into its HCS. Employees who complete the course will be prepared to recognize new GHS chemical labels, use revised classification criteria, and read 16-section Safety Data Sheets (SDSs).