Learn about hazard and caution signs you may see at UC San Diego and what they mean.
Hazard and caution signs identify facilities where work involves hazardous chemicals, infectious biological agents, radioactive materials, or equipment such as lasers, high voltage systems, or powerful magnets. These materials and equipment are generally controlled and contained, and their hazards minimized.
Do not enter an area with a sign that warns against unauthorized entry or says Keep Out, unless specifically authorized to do so by the principal investigator (PI) who controls the space or the Department Safety Coordinator (DSC) or Department Safety Officer. Hazardous materials and equipment will be secured or removed from the area before service or construction personnel begin work.
Biohazard signs feature the biohazard symbol (black on orange is common) to indicate the use of infectious agents. These are generally well-contained, and researchers are trained to disinfect work areas after use.

Carcinogen signs indicate the use of known human carcinogens. These are generally well-contained. Researchers are trained to carefully identify where carcinogens are being used and to decontaminate work areas after their use.

Hazardous waste signs identify collection areas for hazardous wastes.

High voltage signs signal a sustained voltage of more than 600 volts.

Laser signs indicate the presence of high energy laser equipment.

Magnetic field signs designate facilities housing large research magnets that create a powerful static magnetic field.

Radiation signs indicate that the room contains certain quantities of radioactive material.

Clearance tags communicate whether a vacated research facility has or has not been cleared for entry. (When a research group vacates a laboratory, EH&S performs a clearance survey to ensure hazards are not left behind.)
A red clearance tag indicates clearance procedures are in progress.

EH&S posts a green clearance tag when a facility or equipment is cleared of known hazards.