If you worked in a factory at the height of the Industrial Revolution, perhaps one straight from the pages of a Charles Dickens novel, you would not have seen many Danger or Caution signs. If your employer did not want to put up any signs, no one could make the employer do so.

Of course, that was then. Nowadays, OSHA insists that employers take careful steps to protect workers from hazards, and one component of preventing workplace accidents is to put up safety signs.

OSHA’s main regulation governing safety signs is section 1910.145. It says that employers must warn workers of “hazardous or potentially hazardous conditions, equipment or operations which are out of the ordinary, unexpected or not readily apparent.”

What does this require?

There are 5 major categories of accident prevention signs, and here is what the regulation says about each one.

Type of sign

What it is used for

Other information


Indicates immediate danger that requires special precautions Employers must instruct workers that Danger signs mean special precautions must be taken.


A hazard level between “Caution” and “Danger” This is an optional category. Employers may choose to use Danger and Caution signs with no intermediate category.


Warns against potential hazards or cautions against unsafe practices A Caution sign is insufficient if a Danger sign is needed. Also, employers must instruct workers that a Caution sign means proper precaution is required.

Safety Instruction

Communicates general instructions or suggestions relative to safety measures

Biological Hazard

Signifies the actual or potential presence of a biohazard

Are there any other required signs?

Yes. Scattered throughout OSHA regulations are other signage requirements. Here are some examples.

Exit signs

Exit and Not An Exit Safety Signs

OSHA requires “Exit” signs on exits and “Not an Exit” signs on doors that could be mistaken as an exit

Under OSHA regulations, each exit must be marked with an “Exit” sign. Signs may also be needed to show the direction of travel to the nearest exit. In addition, doorways or passages along an exit route that could be mistaken for an exit must have a “Not an Exit” sign or be otherwise marked to show they are not exits.

No smoking signs

No Smoking Safety Signs

“No Smoking” signs may be required by OSHA

Many OSHA regulations require “No Smoking” signs when flammable materials are used.

Numerous other OSHA regulations require employers who engage in certain types of industrial processes or who work with certain types of materials to post safety signs.

Do states have their own signage requirements?

In some states (less than half), the OSHA program is administered by the state itself rather than the feds, and some of these states have tacked additional requirements onto their standards. To find out whether your state is one of them, use the Directory of States with OSHA-Approved Occupational Safety and Health Plans.

Summing up

The day for factories like Dickens’ fictitious Coketown should now be long past. Workplace safety is mandated by OSHA. Signage plays an important role in keeping workers safe and preventing accidents.

Disclaimer: Although every effort has been made to provide accurate information, including having this document reviewed by an OSHA official, InSite Solutions expressly disclaims all warranties and liability of any type whatsoever relating to the use of this document. Any questions about signage requirements may be directed to OSHA.

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