 | This article mayrequirecleanup to meet Wikipedia'squality standards. The specific problem is:This article is mostly covering the hazard signs on substances and should be more specific and renamed. Please helpimprove this article if you can.(August 2024) (Learn how and when to remove this message) |
Hazard symbols are universally recognizedsymbols designed to alert individuals to the presence ofhazardous or dangerous materials, locations, or conditions. These include risks associated withelectromagnetic fields,electric currents, toxic chemicals,explosive substances, andradioactive materials. Their design and use are often governed by laws and standards organizations to ensure clarity and consistency. Hazard symbols may vary in color, background, borders, or accompanying text to indicate specific dangers and levels of risk, such as toxicity classes. These symbols provide a quick, universally understandable visual warning that transcends language barriers, making them more effective than text-based warnings in many situations.
| Standard | Warning | Scope | Audience | State |
|---|---|---|---|---|
| ISO 7010 warning symbols |  | General purpose warning symbols | The general public | Currently used |
| GHS hazard pictograms |  | The labelling of containers and for workplace hazard warnings, and for use during the transport of dangerous goods | The general public, the workplace, and material transport personnel | Currently used |
| EU Directive 67/548/EEC |  | The labelling of containers in the EU, used until 2017 | Mixtures of chemicals that areplaced on the market in theEuropean Union | No longer used |
| WHMIS 1988 |  | Workplace hazard warnings used in Canada, mostly replaced byGHS as of 2018 | Workplace Hazards in Canada | No longer used, except biological hazard symbol |
| Warning | ISO 7010 | ANSI Z535 (United States)[a] |
|---|---|---|
| General warning sign |  | — |
| Flammable material | |  |
| Explosive materials |  |  |
| Toxic material |  |  |
| Corrosive substance |  |  |
| Electricity hazard |  |  |
| Radioactive material or ionizing radiation |  |  |
| Biological hazard |  |  |
| Floor-level obstacle |  |  |
| Drop or fall hazard |  |  |
| Slippery surface |  |  |
Tape with yellow and black diagonal stripes is commonly used as a generic hazard warning. This can be in the form ofbarricade tape, or as a self-adhesive tape for marking floor areas and the like. In some regions (for instance the UK)[1] yellow tape is buried a certain distance above buried electrical cables to warn futuregroundworkers of the hazard.
On roadside warning signs, anexclamation mark is often used to draw attention to a generic warning of danger, hazards, and the unexpected. In Europe and elsewhere in the world (except North America and Australia), this type of sign is used if there are no more-specific signs to denote a particular hazard.[2][3] When used for traffic signs, it is accompanied by a supplementary sign describing the hazard, usually mounted under the exclamation mark.
This symbol has also been more widely adopted for generic use in many other contexts not associated with road traffic. It often appears on hazardous equipment, in instruction manuals to draw attention to a precaution, on tram/train blind spot warning stickers and on natural disaster (earthquake, tsunami, hurricane, volcanic eruption) preparedness posters/brochures—as an alternative when a more-specific warning symbol is not available.
| ☠ | |
|---|---|
Hazard symbol | |
| In Unicode | U+2620 ☠SKULL AND CROSSBONES |
The skull-and-crossbones symbol, consisting of ahuman skull and two bones crossed together behind the skull, is today generally used as a warning of danger ofdeath, particularly in regard topoisonous substances.
The symbol, or some variation thereof, specifically with the bones (or swords) below the skull, was also featured on theJolly Roger, the traditionalflag of European and American seagoingpirates. It is also part of the CanadianWHMIS home symbols placed on containers to warn that the contents are poisonous.
In the United States, due to concerns that the skull-and-crossbones symbol's association with pirates might encourage children to play with toxic materials, theMr. Yuk symbol is also used to denote poison.
This symbol has also been more widely adopted for generic use in many other contexts not associated with poisonous materials. It used for denoting number of dead victims caused by natural disasters (e.g. earthquakes) or armed conflicts on event infographics.
| ☢ | |
|---|---|
Radioactive sign | |
| In Unicode | U+2622 ☢RADIOACTIVE SIGN |
Theinternational radiation symbol is atrefoil around a small central circle representing radiation from an atom. It was designed by mechanical engineerCyrill Orly in 1946 at theUniversity of California, Berkeley Radiation Laboratory.[4] When thefirst radiation hazard signs were created, they were rendered asmagenta, and was set on ablue background. The shade of magenta used (Martin Senour Roman Violet No. 2225) was chosen because it was expensive and less likely to be used on other signs.[5] However, a blue background for other signs started to be used extensively. Blue was typically used on information signs and the color tended to fade with weathering. This resulted in the background being changed on the radiation hazard sign.[6] The original version used in the United States is magenta against a yellow background, and it is drawn with a central circle of radiusR, an internal radius of 1.5R and an external radius of 5R for the blades, which are separated from each other by 60°. The trefoil is black in the international version, which is also used in the United States.[7]
The symbol was adopted as a standard in the US byANSI in 1969.[6][8] It was first documented as an international symbol in 1963 inInternational Organization for Standardization (ISO) recommendation R.361.[9] In 1974, after approval by national standards bodies, the symbol became aninternational standard asISO 361Basic ionizing radiation symbol.[10] The standard specifies the shape, proportions, application and restrictions on the use of the symbol. It may be used to signify the actual or potential presence of ionizing radiation. It is not used for non-ionizing electromagnetic waves or sound waves. The standard does not specify the radiation levels at which it is to be used.[10]
The sign is commonly referred to as aradioactivity warning sign, but it is actually a warning sign ofionizing radiation. Ionizing radiation is a much broader category than radioactivity alone, as many non-radioactive sources also emit potentially dangerous levels of ionizing radiation. This includes x-ray apparatus, radiotherapy linear accelerators, and particle accelerators.Non-ionizing radiation can also reach potentially dangerous levels, but this warning sign is different from the trefoil ionizing radiation warning symbol.[11] The sign is not to be confused with thefallout shelter identification sign introduced by theOffice of Civil Defense in 1961. This was originally intended to be the same as the radiation hazard symbol but was changed to a slightly different symbol because shelters are a place of safety, not of hazard.[6][12]
On February 15, 2007, two groups—theInternational Atomic Energy Agency (IAEA) and theInternational Organization for Standardization (ISO)—jointly announced the adoption of a new ionizing radiation warning symbol to supplement the traditional trefoil symbol. The new symbol, to be used on sealed radiation sources, is aimed at alerting anyone, anywhere to the danger of being close to a strong source of ionizing radiation.[13] It depicts, on a red background, a black trefoil with waves of radiation streaming from it, along with a blackskull and crossbones, and a running figure with an arrow pointing away from the scene. The radiating trefoil suggests the presence of radiation, while the red background and the skull and crossbones warn of danger. The figure running away from the scene is meant to suggest taking action to avoid the labeled material. The new symbol is not intended to be generally visible, but rather to appear on internal components of devices that house radiation sources so that if anybody attempts to disassemble such devices they will see an explicit warning not to proceed any further.[14][15]
| ☣ | |
|---|---|
Hazard symbol | |
| In Unicode | U+2623 ☣BIOHAZARD SIGN |
Thebiohazard symbol is used in the labeling of biological materials that carry a significant health risk, including viral and bacteriological samples, including infected dressings and usedhypodermic needles (seesharps waste).[16]
The biohazard symbol was developed in 1966 byCharles Baldwin, an environmental-health engineer working for theDow Chemical Company on their containment products.[17]
According to Baldwin, who was assigned by Dow to its development: "We wanted something that was memorable but meaningless, so we could educate people as to what it means." In an article inScience in 1967, the symbol was presented as the new standard for all biological hazards ("biohazards"). The article explained that over 40 symbols were drawn up by Dow's artists, and all of the symbols investigated had to meet a number of criteria: "(i) striking in form in order to draw immediate attention; (ii) unique and unambiguous, in order not to be confused with symbols used for other purposes; (iii) quickly recognizable and easily recalled; (iv) easily stenciled; (v) symmetrical, in order to appear identical from all angles of approach; and (vi) acceptable to groups of varying ethnic backgrounds." The chosen scored the best on nationwide testing for uniqueness and memorability.[16]
All parts of the biohazard sign can be drawn with acompass and straightedge. The basic outline of the symbol is a plaintrefoil, which is three circles overlapping each other equally like in a tripleVenn diagram with the overlapping parts erased. Thediameter of the overlapping part is equal to half theradius of the three circles. Then three inner circles are drawn in with2⁄3 radius of the original circles so that it istangent to the outside three overlapping circles. A tiny circle in center has adiameter1⁄2 of the radius of the three inner circles, andarcs are erased at 90°, 210°, and 330°. The arcs of the inner circles and the tiny circle are connected by a line. Finally, the ring under is drawn from the distance to theperimeter of theequilateral triangle that forms between the centers of the three intersecting circles. An outer circle of the ring under is drawn and finally enclosed with the arcs from the center of the inner circles with a shorter radius from the inner circles.[7]
Achemical hazard symbol is apictogram applied to containers and storage areas of dangerouschemical compounds to indicate the specific hazard, and thus the required precautions. There are several systems of labels, depending on the purpose, such as on the container for transportation, containers for end-use, or on a vehicle during transportation.
| Hazard | GHS[b] | ISO 7010[19] | European Union Directive 92/58/EEC[20] | European Union Directive 67/548/EEC[21] | WHMIS 1988[c] |
|---|---|---|---|---|---|
Current | Amended[23] | ||||
| Explosive substance |  | |  |  | — |
| Flammable substance | | |  | | |
| Oxidizing substance |  |  |  |  |  |
| Compressed Gas |  |  | — | — |  |
| Corrosive substance |  | |  |  |  |
| Toxic substance | | |  |  |  |
| Irritant/harmful |  | — |  |  |  |
| Health hazard |  |  | — | — | |
| Environmental hazard |  |  | — |  | — |
| Biological hazard | — | |  | — |  |
| Dangerously reactive substance[d] | — | — | — | — |  |
TheUnited Nations has designedGHS hazard pictograms andGHS hazard statements tointernationally harmonize chemical hazard warnings under theGlobally Harmonized System of Classification and Labelling of Chemicals. These symbols have gradually replaced nation and region specific systems such as the European Union'sDirective 67/548/EEC symbols,[24] Canada's Workplace Hazardous Materials Information System.[25] It has also been adopted in theUnited States for materials being sold and shipped by manufacturers, distributors and importers.[26] The USA previously did not mandate a specific system, instead allowing any system, provided it had met certain requirements.[27]
The European Union employs a standardized system of hazard symbols to communicate the risks associated with chemicals and other hazardous substances. These symbols are regulated primarily under theClassification, Labelling and Packaging (CLP) Regulation, which aligns the EU with theGlobally Harmonized System of Classification and Labelling of Chemicals (GHS) developed by the United Nations.
Implemented on January 20, 2009, theCLP Regulation replaced previous EU directives such as:
The regulation ensures that the hazards presented by chemicals are clearly communicated through standardized labels andhazard pictograms, allowing safe use, handling, and transport throughout the EU.
Before the adoption of GHS, the EU usedorange square symbols under the Dangerous Substances Directive. These included:
These older symbols were phased out byJune 1, 2015.
The Workplace Hazardous Materials Information System, or WHMIS, isCanada's national workplace hazard communication standard, first introduced in 1988, and included eight chemical hazard symbols.[28] This system was brought into alignment with GHS in 2015, with a gradual phase in of GHS symbols and label designs through 15 December 2025.[25] The WHMIS system does deviate from GHS by retaining the former WHMIS symbol for Class 3, Division 3,biohazardous infectious materials, as GHS lacks a biological hazard symbol.[25]
A large number of warning symbols with non-standard designs are in use around the world.
Some warning symbols have been redesigned to be more comprehensible to children, such as theMr. Ouch (depicting an electricity danger as a snarling, spiky creature) andMr. Yuk (a green frowny face sticking its tongue out, to represent poison) designs in the United States.
The three-bladed radiation warning symbol, as we currently know it, was "doodled" out at the University of California Radiation Laboratory in Berkeley sometime in 1946 by a small group of people.
(a) warning sign 'Harmful or irritant material' is deleted.
| Fields | |
|---|---|
| Concepts | |
| Treatments | |
| Incidents | |
| Related topics | |
