3.1 ACUTE MAMMALIAN TOXICITY
Criteria
Applying GHS criteria, a chemical shall not have a median lethal dose or concentration less than or equal to those values listed in Table 1. For inhalation studies, exposure duration should be at least four hours; the thresholds for inhalation are the same for exposures greater than four hours. Exposures of less than four hours will be evaluated on a case-by-case basis.
Table 1 – GHS Thresholds
Route of Exposure | Median Lethal Dose/Concentration |
| Oral LD50 (mg/kg bw) | 2000 |
| Dermal LD50 (mg/kg bw) | 2000 |
| Inhalation, gas LC50 (ppmV) | 5000 |
| Inhalation, vapor LC50 (mg/L) | 20 |
| Inhalation, dust/mist/fumes LC50 (mg/L) | 5 |
Additionally, a chemical does not pass the Criteria if it carries one of the following EU Risk Phrases, which align with GHS thresholds:
Table 2 – Acute Toxicity Risk Phrases
R20 | Harmful by inhalation |
| R21 | Harmful in contact with skin |
| R22 | Harmful if swallowed |
| R23 | Toxic by inhalation |
| R24 | Toxic in contact with skin |
| R25 | Toxic if swallowed |
| R26 | Very toxic by inhalation |
| R27 | Very toxic in contact with skin |
| R28 | Very toxic if swallowed |
| And all combination risk phrases containing one or more of the above. |
Data Requirements
All available data, measured and/or estimated, for the chemical and/or a suitable analog will be reviewed against the criteria using a weight-of-evidence approach.
Test Methods for GHS Review
– OPPTS Harmonized Guideline 870.1100: Acute oral toxicity [6];
– OPPTS Harmonized Guideline 870.1200: Acute dermal toxicity [7]
– OPPTS Harmonized Guideline 870.1300: Acute inhalation toxicity [8];
– OECD Test Guideline 420: Acute Oral Toxicity-Fixed Dose Method [9];
– OECD Test Guideline 423: Acute Oral Toxicity – Acute Toxic Class Method [10];
– OECD Test Guideline 425: Acute Oral Toxicity – Up-and-Down Procedure [11];
– OECD Test Guideline 402: Acute Dermal Toxicity [12]; and
– OECD Test Guideline 403: Acute Inhalation Toxicity [13].
Data Interpretation
For additional information, see GHS Ch 3.1 Acute Toxicity [14].
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