GHS Hazard Rules
This guide outlines our GHS classification rules and the mapping of hazard statements to Tiers.
Tier Level Rule for GHS H-codes and Reasons for Separation
The Rule: A hazard code is assigned to Tier 1 if its GHS Category contains a "1" or a "2" OR if its Signal Word is "Danger". If neither of these conditions is met, the code is assigned to Tier 2.
Reasons for Separation: The Globally Harmonized System (GHS) classifies health and environmental hazards to harmonize chemical regulations globally. While the GHS does not explicitly use this specific "Tier 1 / Tier 2" grouping, applying this rule effectively separates the hazards based on severity. The classifications captured in Tier 1 (Categories 1 and 2, and the "Danger" signal word) represent the most acute and severe health and environmental hazards—such as chemicals that are fatal, toxic, carcinogenic, mutagenic, or cause severe burns. Conversely, the classifications captured in Tier 2 (Categories 3 through 5, and the "Warning" signal word) generally denote lower-severity risks, such as substances that are merely "harmful," cause mild irritation, or pose lower-level environmental risks.
Health and Environmental Hazard Codes (H3XX & H4XX)
The table below extracts the hazard codes, hazard statements, categories, and signal words from the GHS data, along with their evaluated Tier Level. (Note: Where a signal word is omitted or shown as a hyphen in the source text, it is marked as "Not specified" or "-" here).
| H-Code | Hazard Statements | Category | Signal Word | Tier Level | Tier Class |
|---|---|---|---|---|---|
| H300 | Fatal if swallowed | 1, 2 | Danger | 1 | ORL |
| H301 | Toxic if swallowed | 3 | Danger | 1 | ORL |
| H302 | Harmful if swallowed | 4 | Warning | 2 | ORL |
| H303 | May be harmful if swallowed | 5 | Warning | 2 | ORL |
| H304 | May be fatal if swallowed and enters airways | 1 | Danger | 1 | ORL, IHL |
| H305 | May be harmful if swallowed and enters airways | 2 | Warning | 1 | ORL, IHL |
| H310 | Fatal in contact with skin | 1, 2 | Danger | 1 | SKN |
| H311 | Toxic in contact with skin | 3 | Danger | 1 | SKN |
| H312 | Harmful in contact with skin | 4 | Warning | 2 | SKN |
| H313 | May be harmful in contact with skin | 5 | Warning | 2 | SKN |
| H314 | Causes severe skin burns and eye damage | 1, 1A, 1B, 1C | Danger | 1 | SKN |
| H315 | Causes skin irritation | 2 | Warning | 1 | SKN |
| H316 | Causes mild skin irritation | 3 | Warning | 2 | SKN |
| H317 | May cause an allergic skin reaction | 1, 1A, 1B | Warning | 1 | SKN |
| H318 | Causes serious eye damage | 1 | Danger | 1 | SKN |
| H319 | Causes serious eye irritation | 2A | Warning | 1 | SKN |
| H320 | Causes eye irritation | 2B | Warning | 1 | SKN |
| H330 | Fatal if inhaled | 1, 2 | Danger | 1 | IHL |
| H331 | Toxic if inhaled | 3 | Danger | 1 | IHL |
| H332 | Harmful if inhaled | 4 | Warning | 2 | IHL |
| H333 | May be harmful if inhaled | 5 | Warning | 2 | IHL |
| H334 | May cause allergy or asthma symptoms or breathing difficulties if inhaled | 1, 1A, 1B | Danger | 1 | IHL |
| H335 | May cause respiratory irritation | 3 | Warning | 2 | IHL |
| H336 | May cause drowsiness or dizziness | 3 | Warning | 2 | IHL |
| H340 | May cause genetic defects | 1, 1A, 1B | Danger | 1 | CMR |
| H341 | Suspected of causing genetic defects | 2 | Warning | 1 | CMR |
| H350 | May cause cancer | 1, 1A, 1B | Danger | 1 | CMR |
| H350i | May cause cancer by inhalation | 1, 1A, 1B | Danger | 1 | CMR |
| H351 | Suspected of causing cancer | 2 | Warning | 1 | CMR |
| H360 | May damage fertility or the unborn child | 1, 1A, 1B | Danger | 1 | CMR |
| H360F | May damage fertility | 1, 1A, 1B | Danger | 1 | CMR |
| H360D | May damage the unborn child | 1, 1A, 1B | Danger | 1 | CMR |
| H360FD | May damage fertility; May damage the unborn child | 1, 1A, 1B | Danger | 1 | CMR |
| H360Fd | May damage fertility; Suspected of damaging the unborn child | 1, 1A, 1B | Danger | 1 | CMR |
| H360Df | May damage the unborn child; Suspected of damaging fertility | 1, 1A, 1B | Danger | 1 | CMR |
| H361 | Suspected of damaging fertility or the unborn child | 2 | Warning | 1 | CMR |
| H361f | Suspected of damaging fertility | 2 | Warning | 1 | CMR |
| H361d | Suspected of damaging the unborn child | 2 | Warning | 1 | CMR |
| H361fd | Suspected of damaging fertility; Suspected of damaging the unborn child | 2 | Warning | 1 | CMR |
| H362 | May cause harm to breast-fed children | Additional category | Not specified | 1 | CMR |
| H370 | Causes damage to organs | 1 | Danger | 1 | OGN |
| H371 | May cause damage to organs | 2 | Warning | 1 | OGN |
| H372 | Causes damage to organs through prolonged or repeated exposure | 1 | Danger | 1 | OGN |
| H373 | May causes damage to organs through prolonged or repeated exposure | 2 | Warning | 1 | OGN |
| H400 | Very toxic to aquatic life | 1 | Warning | 1 | ENV |
| H401 | Toxic to aquatic life | 2 | - | 1 | ENV |
| H402 | Harmful to aquatic life | 3 | - | 2 | ENV |
| H410 | Very toxic to aquatic life with long lasting effects | 1 | Warning | 1 | ENV |
| H411 | Toxic to aquatic life with long lasting effects | 2 | - | 1 | ENV |
| H412 | Harmful to aquatic life with long lasting effects | 3 | - | 2 | ENV |
| H413 | May cause long lasting harmful effects to aquatic life | 4 | - | 2 | ENV |
| H420 | Harms public health and the environment by destroying ozone in the upper atmosphere | 1 | Warning | 1 | ENV |
| H421 | Harms public health and the environment by contributing to global warming | 1 | Warning | 1 | ENV |
| H300+H310 | Fatal if swallowed or in contact with skin | 1, 2 | Danger | 1 | ORL, SKN |
| H300+H330 | Fatal if swallowed or if inhaled | 1, 2 | Danger | 1 | ORL, IHL |
| H310+H330 | Fatal in contact with skin or if inhaled | 1, 2 | Danger | 1 | IHL, SKN |
| H300+H310+H330 | Fatal if swallowed, in contact with skin or if inhaled | 1, 2 | Danger | 1 | IHL, SKN, ORL |
| H301+H311 | Toxic if swallowed or in contact with skin | 3 | Danger | 1 | ORL, SKN |
| H301+H331 | Toxic if swallowed or if inhaled | 3 | Danger | 1 | ORL, IHL |
| H311+H331 | Toxic in contact with skin or if inhaled | 3 | Danger | 1 | IHL, SKN |
| H301+H311+H331 | Toxic if swallowed, in contact with skin or if inhaled | 3 | Danger | 1 | IHL, SKN, ORL |
| H302+H312 | Harmful if swallowed or in contact with skin | 4 | Warning | 2 | ORL, SKN |
| H302+H332 | Harmful if swallowed or if inhaled | 4 | Warning | 2 | ORL, IHL |
| H312+H332 | Harmful in contact with skin or if inhaled | 4 | Warning | 2 | SKN, IHL |
| H302+H312+H332 | Harmful if swallowed, in contact with skin or if inhaled | 4 | Warning | 2 | ORL, SKN, IHL |
| H303+H313 | May be harmful if swallowed or in contact with skin | 5 | Warning | 2 | ORL, SKN |
| H303+H333 | May be harmful if swallowed or if inhaled | 5 | Warning | 2 | ORL, IHL |
| H313+H333 | May be harmful in contact with skin or if inhaled | 5 | Warning | 2 | SKN, IHL |
| H303+H313+H333 | May be harmful if swallowed, in contact with skin or if inhaled | 5 | Warning | 2 | ORL, SKN, IHL |
| H315+319 | Cause skin irritation and serious eys irritation | 2, 2A | Warning | 1 | SKN |
| H315+H320 | Cause skin and eye irritation | 2, 2B | Warning | 1 | SKN |
