| Halothane | 1 | 1 | 4 | 4 | 4 | 4 |
| Halowax Oil | 1 | 1 | 4 | 4 | 4 | 4 |
| Hannifin Lube A | 1 | 1 | 4 | 1 | 1 | 1 |
| Heavy Water | 1 | 2 | 1 | 1 | 1 | 2 |
| HEF-2 (High Energy Fuel 2) | 1 | 1 | 4 | 2 | 2 | 4 |
| Helium | 1 | 1 | 1 | 1 | 1 | 1 |
| n-Heptane | 3 | 1 | 4 | 1 | 1 | 2 |
| Hexachloroacetone | 4 | 4 | 1 | 4 | 4 | 3 |
| n-Hexane | 2 | 1 | 4 | 1 | 1 | 2 |
| n-Hexene-1 | 3 | 1 | 4 | 2 | 2 | 2 |
| Hi-Lo MS No. 1 | 3 | 4 | 1 | 4 | 4 | 4 |
| High Viscosity Lubricant H2 | 1 | 1 | 1 | 1 | 1 | 2 |
| High Viscosity Lubricant U4 | 1 | 1 | 1 | 1 | 1 | 2 |
| Houghto-Safe 271 (Water + Gylcol) | 1 | 2 | 1 | 1 | 1 | 2 |
| Houghto-Safe 620 (Water + Gylcol) | 1 | 2 | 1 | 1 | 1 | 2 |
| Hydraulic Oil (Petroleum) | 1 | 1 | 4 | 1 | 1 | 2 |
| Hydrazine | 1 | 4 | 1 | 2 | 2 | 2 |
| Hydrobromic Acid | 1 | 1 | 1 | 4 | 4 | 2 |
| Hydrochloric Acid (Cold) 37% | 1 | 1 | 1 | 2 | 2 | 2 |
| Hydrochloric Acid (Hot) 37% | 1 | 2 | 3 | 4 | 4 | 4 |
| Hydrocyanic Acid | 1 | 1 | 1 | 2 | 2 | 2 |
| Hydrofluoric Acid | 2 | 3 | 4 | 4 | 4 | 4 |
| Hydrogen | 1 | 1 | 1 | 1 | 1 | 1 |
| Hydrogen Chloride, Gas | 1 | 1 | 1 | 4 | 4 | 2 |
| Hydrogen Cyanide | 1 | 1 | 1 | 1 | 4 | 2 |
| Hydrogen Peroxide | 1 | 1 | 1 | 2 | 2 | 1 |
| Hydrogen Sulfide, Dry Cold | 1 | 4 | 1 | 1 | 1 | 1 |
| Hydrogen Sulfide, Dry Hot | 1 | 4 | 1 | 4 | 4 | 2 |
| Hydrogen Sulfide, Wet Cold | 1 | 4 | 1 | 4 | 4 | 1 |
| Hydrogen Sulfide, Wet Hot | 2 | 4 | 1 | 4 | 4 | 2 |
| Hydrolube (Water + Glycol) | 1 | 1 | 1 | 1 | 1 | 2 |
| Hydroquinol | 3 | 3 | 4 | 4 | 4 | 4 |
| Hydroquinone | 3 | 3 | 4 | 4 | 4 | 4 |
| Hyjet S 4 | 2 | 4 | 1 | 4 | 4 | 4 |
| Hyjet W | 2 | 4 | 1 | 4 | 4 | 4 |
| Hyjet | 2 | 4 | 1 | 4 | 4 | 4 |
| Industron FF44 | 1 | 1 | 4 | 1 | 1 | 2 |
| Industron FF48 | 1 | 1 | 4 | 1 | 1 | 2 |
| Industron FF53 | 1 | 1 | 4 | 1 | 1 | 2 |
| Industron FF80 | 1 | 1 | 4 | 1 | 1 | 2 |
| Iodine Pentafluoride | 4 | 4 | 4 | 4 | 4 | 4 |
| Iodine | 1 | 1 | 2 | 2 | 1 | 4 |
| Isobutyl Alcohol (Isobutanol, Isopropyl Carbinol) | 1 | 1 | 1 | 2 | 2 | 2 |
| Isobutyl Chloride | 4 | 1 | 4 | 4 | 4 | 4 |
| Isobutyl Ether | 4 | 4 | 4 | 2 | 2 | 3 |
| Isobutyraldehyde | 4 | 4 | 2 | 3 | 2 | 3 |
| Isobutyric Acid | 3 | 4 | 2 | 2 | 2 | 4 |
| Isododecane | 1 | 1 | 4 | 1 | 1 | 2 |
| Isophorone | 2 | 4 | 1 | 4 | 4 | 4 |
| Isopropanol | 1 | 1 | 1 | 2 | 2 | 2 |