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EPA Signal Words

What are Signal Words?

Signal words are found on pesticide product labels, and they describe the acute (short-term) toxicity of the formulated pesticide product. The signal word can be either:

DANGER, WARNING or CAUTION. Products with the DANGER signal word are the most toxic.

See the table below titled “Toxicity Category.”means the pesticide product is slightly toxic if eaten, absorbed through the skin, inhaled, or it causes slight eye or skin irritation.

CAUTION / PRECAUCION

Products with the signal word CAUTION are lower in toxicity.Protection Agency (EPA) requires a signal word on most pesticide product labels. They also require it to be printed on the front panel, in all capital letters, to make it easy for users to find. The only pesticide products that are not required to display a signal word are those that fall into the lowest toxicity category by all routes of exposure (oral, dermal, inhalation, and other effects like eye and skin irritation).

WARNING / AVISO

Indicates the pesticide product is moderately toxic if eaten, absorbed through the skin, inhaled, or it causes moderate eye or skin irritation.

DANGER / PELIGRO

Means that the pesticide product is highly toxic by at least one route of exposure. It may be corrosive, causing irreversible damage to the skin or eyes. Alternatively, it may be highly toxic if eaten, absorbed through the skin, or inhaled. If this is the case, then the word “POISON” must also be included in red letters on the front panel of the product label.

Table 1. 

Toxicity categories.

Study

Category I

Category II

Category III

Category IV

Acute oral

Up to and including 50 mg/kg

>50 through 500 mg/kg

>500 through 5,000 mg/kg

>5,000 mg/kg

Acute dermal

Up to and including 200 mg/kg

>200 through 2,000 mg/kg

>2,000 through 5,000 mg/kg

>5,000 mg/kg

Acute inhalation*

Up to and including 0.05 mg/liter

>0.05 through 0.5 mg/liter

>0.5 through 2 mg/liter

>2 mg/liter

Primary eye irritation

Corrosive (irreversible destruction of ocular tissue) or corneal involvement or irritation persisting for more than 21 days

Corneal involvement or other eye irritation clearing in 8-21 days

Corneal involvement or other eye irritation clearing in 7 days or less

Minimal effects clearing in less than 24 hours

Primary skin irritation

Corrosive (tissue destruction into the dermis and/or scarring)

Severe irritation at 72 hours (severe erythema or edema)

Moderate irritation at 72 hours (moderate erythema)

Mild or slight irritation at 72 hours (no irritation or slight erythema)

*4-hour exposure.

Table 2. 

Signal word as determined by toxicity category.

Toxicity category

Signal word

I

DANGER

II

WARNING

III

CAUTION

IV

None required

Table 3. 

Examples of signal words based upon toxicity studies.

Type of study

Product A

Product B

Product C

Product D

Product E

Acute oral

III

IV

I*

III

II

Acute dermal

IV

III

III

IV

II

Acute inhalation

III

IV

III

III

II

Primary eye

III

II

I

I

II

Primary skin

IV

IV

II

IV

II

Contains >4% methanol

No

No

No

No

Yes**

Signal word

CAUTION

WARNING

DANGER

DANGER

DANGER

*Product C must also bear the skull and crossbones symbol in close proximity to the word “POISON” which must appear in red on a contrasting background due to acute oral toxicity.

**Product E must also bear the skull and crossbones symbol in close proximity to the word “POISON” which must appear in red on a contrasting background due to its formulation containing at least 4% methanol.

Table 4. 

Typical statements for acute oral toxicity.

Toxicity category

Signal word

Statements

I

DANGER-POISON Skull and crossbones required*

Fatal if swallowed. Wash thoroughly with soap and water after handling and before eating, drinking, chewing gum, or using tobacco.

II

WARNING

May be fatal if swallowed. Wash thoroughly with soap and water after handling and before eating, drinking, chewing gum, or using tobacco.

III

CAUTION

Harmful if swallowed. Wash thoroughly with soap and water after handling and before eating, drinking, chewing gum, or using tobacco.

IV

CAUTION (optional)

No statements are required. However, manufacturers may choose to use category III labeling.

*For products containing >4% methanol, EPA believes that in order to mitigate potential risk the following statement should be added to the label: “Methanol may cause blindness.”

Table 5. 

Typical statements for acute dermal toxicity.

Toxicity category

Signal word

Statements

I

DANGER-POISON Skull and crossbones required

Fatal if absorbed through skin. Do not get in eyes, on skin, or on clothing. Wash thoroughly with soap and water after handling and before eating, drinking, chewing gum, or using tobacco. Wear (appropriate protective clothing listed here). Remove and wash contaminated clothing before reuse.

II

WARNING

May be fatal if absorbed through skin. Do not get in eyes, on skin, or on clothing. Wash thoroughly with soap and water after handling and before eating, drinking, chewing gum, or using tobacco. Wear (appropriate protective clothing listed here). Remove and wash contaminated clothing before reuse.

III

CAUTION

Harmful if absorbed through skin. Avoid contact with skin, eyes or clothing. Wash thoroughly with soap and water after handling and before eating, drinking, chewing gum, or using tobacco. Wear (appropriate protective clothing listed here). Remove and wash contaminated clothing before reuse.

IV

CAUTION (optional)

No statements are required. However, manufacturers may choose to use category III labeling.

Table 6. 

Typical statements for acute inhalation toxicity.

Toxicity category

Signal word

Statements

I

DANGER-POISON Skull and crossbones required

Fatal if inhaled. Do not breathe (dust, vapor, or spray mist listed here). Wear (appropriate respiratory protection listed here). Remove and wash contaminated clothing before reuse.

II

WARNING

May be fatal if inhaled. Do not breathe (dust, vapor, or spray mist listed here). Wear (appropriate respiratory protection listed here). Remove and wash contaminated clothing before reuse.

III

CAUTION

Harmful if inhaled. Avoid breathing (dust, vapor, or spray mist listed here). Remove and wash contaminated clothing before reuse.

IV

CAUTION (optional)

No statements are required. However, manufacturers may choose to use category III labeling.

Table 7. 

Typical statements for primary eye irritation.

Toxicity category

Signal word

Statements

I

DANGER

Corrosive.* Causes irreversible eye damage. Do not get in eyes or on clothing. Wear (appropriate protective eyewear such as goggles, face shield, or safety glasses listed here). Wash thoroughly with soap and water after handling and before eating, drinking, chewing gum, or using tobacco. Remove and wash contaminated clothing before reuse.

II

WARNING

Causes substantial but temporary eye injury. Do not get in eyes or on clothing. Wear (appropriate protective eyewear such as goggles, face shield, or safety glasses listed here). Wash thoroughly with soap and water after handling and before eating, drinking, chewing gum, or using tobacco. Remove and wash contaminated clothing before reuse.

III

CAUTION

Causes moderate eye irritation. Avoid contact with eyes or clothing. Wear (specify protective eyewear, if appropriate, here). Wash thoroughly with soap and water after handling and before eating, drinking, chewing gum, or using tobacco.

IV

CAUTION (optional)

No statements are required. However, manufacturers may choose to use category III labeling.

*The term “corrosive” is not required if corrosive effects were not observed during the study.

Table 8. 

Typical statements for primary skin irritation.

Toxicity category

Signal word

Statements

I

DANGER

Corrosive. Causes skin burns. Do not get in eyes, on skin, or on clothing. Wear (appropriate protective clothing and gloves listed here). Wash thoroughly with soap and water after handling and before eating, drinking, chewing gum, or using tobacco. Remove and wash contaminated clothing before reuse.

II

WARNING

Causes skin irritation. Do not get on skin or on clothing. Wear (appropriate protective clothing and gloves listed here). Wash thoroughly with soap and water after handling and before eating, drinking, chewing gum, or using tobacco. Remove and wash contaminated clothing before reuse.

III

CAUTION

Avoid contact with skin or clothing. Wash thoroughly with soap and water after handling and before eating, drinking, chewing gum, or using tobacco. Wear (appropriate protective clothing and gloves listed here).

IV

CAUTION (optional)

No statements are required. However, manufacturers may choose to use category III labeling.

Table 9. 

Typical statements for dermal sensitization.

Study results

Statement

Product is a sensitizer or is positive for sensitization.

Prolonged or frequently repeated skin contact may cause allergic reactions in some individuals.

Product is not a sensitizer or is negative for sensitization.

No labeling is required for this result.

 

Disclaimer: Exposure to almost any pesticide can cause illness. Some pesticides are so toxic even a small quantity can be dangerous to the operator, bystanders, pets, livestock and wildlife. To apply any pesticide safely, your most important source of information is the label on the container. Read and follow the directions on it.

Please read all pesticide labels prior to use. The information contained at this web site is not a substitute for a pesticide label. Trade names used herein are for convenience only; no endorsement of products is intended, nor is criticism of unnamed products implied. Most of the agri-chemical and pesticide information is historical in nature and may no longer be applicable.