Water, Waste & Pollution
Acute toxicity
The capacity of a substance to cause harm from a single or short-term exposure, classified under the UN Globally Harmonized System into five hazard categories for each exposure route.
Expert review openNo editor-accepted expert review yetDefinition
A health hazard class describing adverse effects that occur following oral or dermal administration of a single dose, multiple doses within 24 hours, or an inhalation exposure of four hours. Under the UN Globally Harmonized System of Classification and Labelling of Chemicals (GHS), acute toxicity is divided into five hazard categories per exposure route, ranked by severity.
References
GHS definitions of hazard class and hazard category; oral acute toxicity's five categories; classification framework.
GHS structure (physical, health, environmental hazard groups); acute toxicity as a health hazard class; purple book revision cycle.
GHS voluntary status at UN level, binding when transposed nationally; acute toxicity among consensus health classes.
Overview
What it means
Acute toxicity is distinct from chronic toxicity (harm from repeated or prolonged exposure) and from hazard classes such as carcinogenicity. GHS classification determines the symbols, signal words and hazard statements on labels and safety data sheets. The corresponding environmental classes cover acute and chronic hazards to the aquatic environment.
How it is used
Regulators and companies use acute toxicity classifications to control chemical handling, transport and worker protection, and to communicate hazards to downstream users. The GHS is voluntary at the international level but becomes binding where countries transpose it into national law; criteria are published in the UNECE "purple book", revised roughly every two years.
Why it matters
Harmonised acute toxicity classification underpins chemical safety, trade and pollution prevention worldwide. In sustainability assessment it feeds life-cycle toxicity indicators and chemical-footprinting, and it is central to due diligence on chemicals in supply chains.
Review
Public comments appear only after editor acceptance. Draft comments stay in the review queue.
Reviewers choose the definition or an overview paragraph, leave a comment or replacement, and attach evidence or a source link.
Editors compare reviewer cards side by side. AI may help find agreement, conflicts, unsupported claims and possible source issues.
Only an editor-accepted synthesis changes the public page. Reviewer identities are shown only with consent and verification.
Submitted reviews stay private until accepted.
Loading verified endorsements… Endorsements are not votes and never determine publication.
Endorse this definition
Endorse the exact version shown here. This is not a vote, and publication remains an editorial decision.
Review board
Comment on a specific line. Each reviewer stays separate until an editor accepts a merged draft.
Each person comments on the definition or overview in their own draft card, with role, evidence and suggested wording kept together.
AI can compare comments against the current text, flag conflicting claims, surface missing evidence and identify where reviewers agree.
An editor merges compatible suggestions into a draft change, checks sources, records disagreements and decides what can be published.