Science Safety Symbols: Complete Guide to Laboratory, Chemical, and Hazard Symbols

Science safety symbols are visual warnings that help people identify hazards in laboratories, classrooms, research facilities, and other scientific environments. They can warn about chemicals, biological materials, radiation, lasers, electricity, ultraviolet light, fire, and other potential dangers.

Learning these symbols is important because a quick look at a pictogram can alert you to a hazard before you handle a substance or enter a restricted area. However, a symbol is only part of the safety message. Chemical labels can also include signal words, hazard statements, precautionary statements, and other information that explains what the hazard is and how to work safely.

This guide explains the most common science safety symbols, what they mean, where they are used, how GHS chemical symbols differ from other laboratory warnings, and how students and laboratory workers should interpret them.

What Are Science Safety Symbols?

Science safety symbols are pictograms or visual signs used to communicate potential hazards and safety requirements.

You may find them on:

• Chemical containers and bottles
• Laboratory doors
• Chemical storage cabinets
• Laboratory equipment
• Radiation-controlled areas
• Biological research areas
• Laser equipment
• Safety posters
• Waste containers
• Safety Data Sheets and chemical documentation

The term science safety symbols is broader than chemical hazard pictograms. A science laboratory can contain chemical, biological, radioactive, laser, physical, animal, and ultraviolet-light hazards, each of which may have its own warning symbol. CDC laboratory-safety guidance identifies several of these categories as common laboratory hazards.

Why Are Science Safety Symbols Important?

Safety symbols provide information quickly. In a laboratory, people may not have time to read a long paragraph before recognizing a potential danger.

A good safety symbol can help someone:

• Recognize a hazard before exposure.
• Identify dangerous chemicals.
• Understand whether a substance can burn, explode, or cause health effects.
• Notice radiation or biological hazards.
• Determine whether special precautions may be necessary.
• Recognize restricted or hazardous laboratory areas.
• Find appropriate safety information.

However, recognizing a symbol does not replace laboratory training. OSHA notes that GHS pictograms are part of a larger hazard communication system, and workers must understand what the symbols mean and how to respond to the hazards they identify.

Science Safety Symbols at a Glance

Here is a quick-reference guide to some of the most common symbols:

Important: The emoji above are only convenient illustrations. Official GHS pictograms use standardized graphical designs, including a black symbol on a white background surrounded by a red diamond-shaped frame.

What Are the Nine GHS Safety Symbols?

The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) uses nine hazard pictograms for communicating chemical hazards. They are coded GHS01 through GHS09.

These symbols cover physical, health, and environmental hazards.

1. Exploding Bomb Symbol

GHS code: GHS01

The exploding-bomb pictogram represents certain explosive hazards, including applicable explosive substances, self-reactive substances, and organic peroxides.

It is one of the most visually obvious science safety symbols because the graphic resembles an explosion.

What it tells you: The material may present an explosion-related hazard under specified conditions.

Where you may see it: Chemical labels, laboratory storage areas, or documentation for appropriately classified substances.

Never treat an exploding-bomb symbol as a general instruction to handle the material carefully without further information. The complete label and relevant safety procedures determine the appropriate precautions.

2. Flame Symbol

GHS code: GHS02

The flame pictogram identifies several fire-related chemical hazards. Depending on the classification, these can include flammables, pyrophoric materials, self-heating substances, substances that emit flammable gas, self-reactive substances, and certain organic peroxides.

What it tells you: The material may ignite or present another specified fire hazard.

Common examples of where you may see it:

• Flammable chemical containers
• Chemical storage cabinets
• Laboratory reagent bottles
• Chemical safety documentation

The exact precaution depends on the substance and its classification.

3. Flame Over Circle Symbol

GHS code: GHS03

The flame-over-circle symbol represents oxidizing hazards.

Oxidizing substances can contribute to combustion or intensify a fire under certain conditions.

What it tells you: The substance can act as an oxidizer and may increase fire risk when it interacts with combustible materials.

This symbol should not be confused with the ordinary flame pictogram. The ordinary flame represents various fire-related hazards, while the flame-over-circle specifically identifies oxidizing substances.

4. Gas Cylinder Symbol

GHS code: GHS04

The gas-cylinder pictogram indicates gases under pressure.

Pressurized gases can present physical hazards associated with pressure and the condition of the container. Some gases may also have additional chemical hazards, so a cylinder can display more than one relevant warning.

What it tells you: The container holds gas under pressure or another applicable pressure-related chemical hazard.

Common locations include:

• Laboratory gas cylinders
• Compressed-gas storage areas
• Chemical labels
• Gas supply systems

Always follow the laboratory’s procedures for transporting, securing, storing, and using compressed-gas cylinders.

5. Corrosion Symbol

GHS code: GHS05

The corrosion pictogram shows a substance affecting a hand and a metal surface.

It identifies specified corrosive hazards, including substances that can cause serious skin burns or eye damage and substances that can corrode metals.

What it tells you: The substance may severely damage tissue, eyes, or certain materials.

This symbol is commonly found on containers of appropriately classified corrosive chemicals.

6. Skull and Crossbones Symbol

GHS code: GHS06

The skull-and-crossbones pictogram identifies specified categories of acute toxicity.

This is a serious hazard symbol because appropriately classified substances can cause severe toxic effects following exposure.

What it tells you: The chemical presents a significant acute toxicity hazard within the applicable classification.

Do not use the symbol alone to determine exactly how exposure can occur or what protective equipment is necessary. Read the complete label and Safety Data Sheet.

7. Exclamation Mark Symbol

GHS code: GHS07

The exclamation-mark pictogram can identify several hazards, including certain categories of:

• Skin irritation
• Eye irritation
• Skin sensitization
• Acute toxicity classified as harmful
• Narcotic effects
• Respiratory tract irritation

The exact hazard depends on the chemical’s classification.

What it tells you: The substance can produce specified harmful or irritating effects.

Because the exclamation mark covers multiple hazard categories, always read the accompanying hazard statement rather than assuming it means only “irritant.”

8. Health Hazard Symbol

GHS code: GHS08

The health-hazard pictogram shows a human silhouette with a star-like mark in the chest.

It identifies certain serious health hazards, including applicable categories of:

• Carcinogenicity
• Germ-cell mutagenicity
• Reproductive toxicity
• Respiratory sensitization
• Target-organ toxicity
• Aspiration toxicity

What it tells you: The chemical may present a specified serious or longer-term health hazard.

This symbol is particularly important because some hazards represented by it may not cause immediate symptoms.

9. Environment Symbol

GHS code: GHS09

The environment pictogram shows a dead tree and fish.

It identifies hazards to the aquatic environment under the GHS classification system.

What it tells you: The substance may pose a specified environmental hazard, particularly to aquatic life.

The environment pictogram is part of the nine-pictogram GHS system. In the United States, OSHA’s Hazard Communication Standard does not require the environmental pictogram because environmental hazards are outside OSHA’s jurisdiction, although the symbol may appear as supplementary information.

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What Do GHS Symbols Look Like?

Official GHS hazard pictograms have a recognizable design.

They generally contain:

• A black hazard symbol
• A white background
• A red diamond-shaped frame
• A standardized pictogram corresponding to the hazard

OSHA specifies that its required chemical pictograms have the shape of a square set at a point, with the black hazard symbol on a white background and a sufficiently wide red frame.

This standardized appearance helps people recognize chemical hazard labels across different products and workplaces.

Why Do Safety Symbols Use Red Diamonds?

The red diamond frame is part of the standardized GHS pictogram design.

The visual format separates the hazard pictogram from ordinary text and makes it easier to identify a warning on a chemical label.

The symbol itself communicates the particular hazard. The surrounding red diamond provides a consistent visual format for GHS chemical hazard communication.

Science Lab Symbols Beyond GHS

Not every laboratory safety symbol is a GHS chemical pictogram.

A laboratory may contain several other types of hazards, including biological, radioactive, laser, ultraviolet, physical, chemical, and animal-related hazards. CDC laboratory-safety materials specifically identify these categories.

Biohazard Symbol

Symbol: ☣️

The biohazard symbol warns about biological hazards.

It can be used in areas where potentially hazardous biological materials are handled, stored, or processed.

Biological hazards may include infectious organisms, human blood or body fluids, and other biological materials that can present health risks.

Where you may see it:

• Microbiology laboratories
• Clinical laboratories
• Biological research facilities
• Certain waste containers
• Restricted laboratory areas

Radiation Symbol

Symbol: ☢️

The radiation trefoil warns about ionizing radiation or radioactive materials.

It can be found around controlled radiation areas, radioactive-material storage locations, or equipment that produces ionizing radiation.

Important: A radiation warning is not equivalent to a chemical hazard pictogram. It belongs to a different safety communication context.

Laser Warning Symbol

Laser warning signs identify areas or equipment where laser radiation may present a hazard.

Laser exposure can potentially damage the eyes or skin, and some lasers can also create fire hazards. CDC laboratory guidance identifies laser hazards as a specific laboratory hazard category.

Appropriate controls depend on the laser and its classification.

Ultraviolet Hazard Symbol

UV warning signs indicate potential exposure to ultraviolet radiation.

UV sources may be used in scientific and laboratory equipment. Depending on the source and procedure, exposure controls can include shielding, restricted access, and appropriate protective equipment.

Electrical Hazard Symbol

Symbol: ⚡

An electrical warning symbol indicates a potential electrical hazard.

It may be used on:

• High-voltage equipment
• Electrical panels
• Laboratory instruments
• Power supplies
• Restricted electrical areas

Never open or service electrical equipment unless you are trained and authorized to do so.

Physical Hazard Symbols

Laboratories can also contain physical hazards involving:

• Heat
• Cold
• Pressure
• Moving machinery
• Sharp equipment
• Noise
• Cryogenic materials
• Other specialized equipment

The exact warning sign depends on the hazard and facility.

Chemical Safety Symbols vs. Laboratory Safety Symbols

These terms are related, but they are not identical.

Chemical safety symbols generally refer to symbols used to communicate chemical hazards, especially GHS pictograms.

Laboratory safety symbols is a broader term that can include warnings for:

• Chemicals
• Biological materials
• Radiation
• Lasers
• UV radiation
• Electricity
• Physical hazards
• Animal hazards

Therefore, GHS symbols are an important part of laboratory safety, but they do not represent every possible hazard found in a science laboratory.

GHS Symbols vs. NFPA 704 Symbols

Another common source of confusion is the difference between GHS pictograms and the NFPA 704 hazard diamond.

They are different systems with different purposes.

GHS

GHS focuses on communicating classified chemical hazards through standardized labels and pictograms.

A GHS label can include:

• Pictograms
• Signal words
• Hazard statements
• Precautionary statements
• Product identification
• Supplier information

NFPA 704

NFPA 704 uses a four-section diamond with numerical ratings intended to communicate specific hazards, particularly for emergency response.

Because the systems have different purposes and rating approaches, an NFPA number should not simply be treated as though it were a GHS hazard category.

GHS Safety Symbols and Signal Words

A chemical label may contain both a pictogram and a signal word.

The two GHS signal words are:

• Danger
• Warning

The signal word communicates the relative severity associated with the applicable hazard classification.

This means you should not stop after identifying a pictogram.

For example, a label may provide:

Pictogram → Signal word → Hazard statement → Precautionary statement

Together, these elements provide much more information than the symbol alone.

Hazard Statements and Precautionary Statements

Hazard Statements

A hazard statement explains the nature of the hazard.

It tells the reader what kind of danger the substance presents.

Precautionary Statements

A precautionary statement explains measures intended to prevent or minimize harmful effects.

These can address:

• Prevention
• Response
• Storage
• Disposal

The GHS framework uses these components as part of its broader chemical hazard communication system.

How to Read a Science Safety Symbol Correctly

Knowing the symbol is useful, but knowing what to do with the information is even more important.

Step 1: Identify the Symbol

First determine what type of hazard is represented.

Is it:

• Chemical?
• Biological?
• Radiation?
• Laser?
• Electrical?
• UV?
• Fire?
• Another physical hazard?

Step 2: Read the Entire Label

Never rely on a pictogram alone.

For chemical products, look for the product identifier, signal word, hazard statements, precautionary statements, and other applicable information.

Step 3: Check the Safety Data Sheet

If you are working with a hazardous chemical, consult its Safety Data Sheet when you need detailed information about hazards, handling, storage, exposure controls, first aid, accidental release, and disposal.

Step 4: Follow Laboratory Procedures

Your school, university, workplace, or research institution may have specific procedures for the substance or equipment.

Step 5: Use Appropriate PPE

The required PPE depends on the actual hazard and procedure. Do not choose protective equipment simply because a symbol looks dangerous.

Step 6: Ask Before Handling an Unfamiliar Hazard

If you do not understand a symbol, label, or procedure, ask the responsible instructor, laboratory supervisor, or safety professional before proceeding.

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Where Are Science Safety Symbols Commonly Used?

You can encounter science safety symbols in many settings.

School Science Laboratories

Students may see warning symbols on:

• Chemical bottles
• Storage cabinets
• Laboratory doors
• Demonstration equipment
• Waste containers

University Laboratories

Research laboratories may use a wider range of symbols because they can involve specialized chemical, biological, radiation, laser, or physical hazards.

Medical and Clinical Laboratories

Clinical environments may use biological, chemical, radiation, and other hazard warnings.

Industrial Laboratories

Industrial research and testing facilities can use chemical, pressure, electrical, machinery, fire, and other safety signs.

Chemical Storage Areas

Chemical storage rooms commonly use hazard communication labels and signs to identify specific risks and restricted areas.

How Students Can Learn Science Safety Symbols

The easiest way to learn science safety symbols is to connect each symbol with its hazard and appropriate response, rather than memorizing the picture alone.

For example:

A student should also learn that the exact meaning and required precaution can depend on the label, classification, equipment, and laboratory procedure.

Common Mistakes When Interpreting Safety Symbols

Mistake 1: Assuming Every Warning Symbol Means the Same Thing

Different symbols communicate different hazards.

A flame, skull-and-crossbones, corrosion, and radiation symbol should never be treated as interchangeable.

Mistake 2: Looking Only at the Picture

A pictogram provides a quick warning, but the written information provides additional details.

Mistake 3: Confusing the Flame With the Flame-Over-Circle

The ordinary flame and flame-over-circle pictograms represent different hazard categories.

Mistake 4: Confusing GHS With NFPA

GHS pictograms and NFPA 704 ratings are separate systems.

Mistake 5: Assuming “Warning” Means Safe

The word Warning is a formal signal word. It does not mean that the substance is harmless.

Mistake 6: Ignoring a Symbol Because You Have Seen It Before

A familiar symbol should still be interpreted in the context of the specific substance, equipment, or location.

Mistake 7: Assuming One Chemical Has Only One Hazard

A chemical can have multiple classified hazards and may therefore require multiple pictograms or hazard statements.

Why Can a Chemical Have More Than One Safety Symbol?

A single chemical can have several different hazards.

For example, a substance may have:

• A fire-related hazard
• A health hazard
• An irritation hazard

The label can communicate multiple applicable hazards using different pictograms and written hazard statements.

This is why reading only one symbol can give you an incomplete understanding of the material.

What Is the Difference Between a Symbol and a Pictogram?

These terms are sometimes used interchangeably, but there is a useful distinction.

A symbol is the visual image representing a particular hazard.

A pictogram can include the symbol together with additional graphic elements such as its standardized frame and background.

Under GHS, the pictogram is the complete graphical composition used to communicate hazard information.

Are Science Safety Symbols Universal?

Not every science safety sign is universal.

GHS chemical pictograms are designed as a harmonized international system, while individual countries, institutions, industries, and laboratories can have additional safety signs and procedures.

The United Nations GHS framework provides standardized chemical hazard communication, while laboratory-specific hazards such as radiation, biological materials, and lasers can use other established warning systems.

Therefore, students and workers should learn both the commonly recognized symbols and the specific safety signs used by their facility.

Frequently Asked Questions About Science Safety Symbols

What are science safety symbols?

Science safety symbols are visual signs and pictograms that communicate hazards in laboratories and scientific environments. They can identify chemical, biological, radiation, laser, electrical, UV, and other hazards.

How many GHS safety symbols are there?

The GHS has nine hazard pictograms, coded GHS01 through GHS09. They cover physical, health, and environmental hazards.

What are the nine GHS symbols?

The nine are:

1. Exploding bomb
2. Flame
3. Flame over circle
4. Gas cylinder
5. Corrosion
6. Skull and crossbones
7. Exclamation mark
8. Health hazard
9. Environment

What does the skull-and-crossbones symbol mean?

It identifies specified categories of acute toxicity and indicates that a chemical can cause serious toxic effects under the applicable exposure conditions.

What does the flame symbol mean?

The GHS flame pictogram identifies several fire-related chemical hazards, including applicable flammable, pyrophoric, self-heating, self-reactive, and related classifications.

What does the corrosion symbol mean?

The corrosion pictogram identifies applicable corrosive hazards, including chemicals that can cause serious skin or eye damage or corrode metals.

What does the biohazard symbol mean?

The biohazard symbol identifies a biological hazard. It can be used in laboratory environments where biological materials may pose a risk.

What does the radiation symbol mean?

The radiation symbol warns about ionizing radiation or radioactive materials in an appropriate controlled area.

Are GHS symbols the same as laboratory safety symbols?

No. GHS symbols specifically address chemical hazard communication, while laboratory safety symbols can cover a broader range of hazards, including biological, radiation, laser, UV, and physical hazards.

What should I do when I see an unfamiliar science safety symbol?

Do not guess. Read the associated warning or label, consult the relevant safety documentation, and ask a qualified instructor, supervisor, or safety professional before handling the material or entering a hazardous area.

Key Takeaways About Science Safety Symbols

The most important things to remember are:

• Science safety symbols communicate hazards quickly.
• GHS provides nine chemical hazard pictograms.
• Not every laboratory warning is a GHS symbol.
• Biohazard and radiation symbols represent different hazard systems.
• A chemical can have more than one applicable pictogram.
• GHS pictograms are only one part of a chemical label.
• Signal words, hazard statements, and precautionary statements provide additional information.
• GHS and NFPA 704 are different systems.
• Always follow your laboratory’s specific safety procedures.
• Never handle an unfamiliar hazardous substance based on the symbol alone.

Final Thoughts

Understanding science safety symbols is one of the foundations of safe laboratory behavior. Whether you are a student learning basic science, a teacher preparing a laboratory lesson, or someone working in a research environment, recognizing common hazard symbols can help you identify potential risks before beginning an activity.

The nine GHS pictograms are especially important for chemical safety, but they are only part of the larger laboratory safety picture. Biological, radiation, laser, UV, electrical, and physical hazards may require different warning symbols and controls.

The safest habit is simple: recognize the symbol, read the complete warning, check the appropriate safety information, and follow the required procedure. A symbol is designed to get your attention, but proper training and complete hazard information tell you what the warning actually means and how to respond.

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Ryan Mitchell

I’m Ryan Mitchell, and I write about modern English, trending slang, and online expressions. I enjoy explaining the meanings, origins, and real-life usage of popular words in a simple way. I believe learning slang is an important step toward understanding today’s English-speaking culture. Through my work, I aim to help readers speak more naturally and stay updated with the latest language trends.