Pre-2007 List of Health Code Numbers (HCNs) Used to Classify Toxic Effects by Target Organ
| HCN | Target Organ |
|---|---|
| 1.00 | OSHA carcinogen (29 CFR 1910.1000) |
| 1.01 | Bladder carcinogen |
| 1.02 | Liver carcinogen |
| 2.00 | Suspect carcinogen or mutagen |
| 2.01 | Kidney carcinogen |
| 2.02 | Liver carcinogen |
| 3.00 | Chronic systemic toxin |
| 3.01 | Bladder |
| 3.02 | Unspecified hematological effects |
| 3.03 | Bone |
| 3.04 | Bone marrow |
| 3.05 | Brain |
| 3.06 | Eye (chronic ocular) |
| 3.07 | Gastrointestinal tract |
| 3.08 | Heart |
| 3.09 | Kidney |
| 3.10 | Liver |
| 3.11 | Skin |
| 3.12 | Skin perforation |
| 4.00 | Acute systemic toxin – short-term high hazard effects |
| 4.01 | Eye (acute, other than irritation) |
| 4.02 | Nose |
| 5.00 | Reproductive toxin |
| 6.00 | Cholinesterase toxin |
| 7.01 | Central nervous system |
| 7.00 | Nervous system toxin |
| 8.00 | Narcotic |
| 9.00 | Respiratory sensitizer |
| 10.00 | Chronic respiratory toxin |
| 11.00 | Acute respiratory toxin |
| 12.00 | Blood toxin- anemia |
| 13.00 | Blood toxin- methemoglobinemia |
| 14.00 | Severe irritant |
| 14.01 | Eye irritant - severe |
| 14.02 | Skin irritant - severe |
| 15.00 | Moderate irritant |
| 15.01 | Eye irritant - moderate |
| 15.02 | Skin irritant - moderate |
| 16.00 | Mild irritant |
| 16.01 | Eye irritant - mild |
| 16.02 | Skin irritant - mild |
| 17.00 | Asphyxiants, anoxiants |
| 18.00 | Explosive, flammable safety (no adverse effects with good housekeeping) |
| 19.00 | Generally low risk health effects – nuisance particles, vapors or gases |
| 20.00 | Generally low risk health effects - odor |
The above information is excerpted from Table 2 in the "Recommended Default Methodology for Analysis of Airborne Exposures to Mixtures of Chemicals in Emergencies."