| Hydrochloric Acid, 15% | 1 | 3 | 3 | 3 | 3 | B |
| Hydrochloric Acid, 37% | 1 | 3 | 3 | 3 | 3 | B |
| Hydrocarbon Acid | 1 | 3 | 1 | 1 | 3 | |
| Hydrofluoric Acid | | | | | | |
| Concetroted | 1 | 3 | 3 | 3 | 3 | |
| Hydrofluosilicic Acid. | 1 | 0 | 3 | 3 | 3 | |
| | | | | | | |
| Hydrogen,Gaseous | - | 1 | 1 | 1 | 1 | C |
| Hydrogen Peroxide. 70% | 1 | 3 | 2 | 1 | 3 | |
| Hydrogen Sulfide, Gaseous | 1 | 3 | 2 | 1 | 3 | |
| Hydroquinone | 0 | 1 | 0 | 1 | 0 | |
| Isobutyl Alcohol | 1 | 1 | 1 | 1 | 2 | |
| | | | | | | |
| Isooctane | 1 | 1 | 1 | 1 | 1 | |
| Isopropyl Acetate | 1 | 1 | 1 | 1 | 1 | |
| Isopropyl Alcohol | 1 | 1 | 1 | 1 | 2 | |
| Isopropyl Ether | 1 | 1 | 1 | 1 | 1 | |
| Kerosene | 1 | 1 | 1 | 1 | 1 | |
| | | | | | | |
| Lacquers | 1 | 3 | 3 | 1 | 1 | |
| Lacquer Solvents | 1 | 3 | 3 | 1 | 1 | B |
| Lactic Acid | 1 | 3 | 2 | 1 | 2 | |
| Lard | 1 | 1 | 1 | 1 | 3 | |
| Lead Acetate | 1 | 2 | 1 | 1 | 1 | |
| | | | | | | |
| Lead Nitrate | 0 | 1 | 1 | 1 | 0 | |
| Lime Bleach | 0 | 3 | 2 | 1 | 0 | |
| Linoleic Acid | 1 | 0 | 0 | 0 | 0 | |
| Linseed Oil | 1 | 2 | 1 | 1 | 2 | |
| Lubricating Oils, Petroleum | 1 | 1 | 1 | 1 | 1 | |
| | | | | | | |
| Magnesium Chloride | 1 | 3 | 2 | 1 | 2 | |
| Magnesium Hydroxide | 1 | 1 | 1 | 1 | 0 | |
| Magnesium Sulfate | 1 | 2 | 1 | 1 | 1 | |
| Malic Acid | 1 | 2 | 2 | 1 | 0 | |
| Mercuric Chloride | 1 | 3 | 1 | 1 | 3 | |
| | | | | | | |
| Mercury | 1 | 1 | 1 | 1 | 3 | |
| Mesityl Oxide | 1 | 1 | 1 | 1 | 1 | |
| Methyl Acetate | 1 | 1 | 1 | 1 | 1 | |
| Methyl Acrylate | 0 | 1 | 1 | 1 | 1 | |
| Methyl Alcohol | 1 | 1 | 1 | 1 | 2 | |
| | | | | | | |
| Methyl Bromide | 1 | 1 | 1 | 1 | 1 | B |
| Methyl Butyl Ketone | 0 | 1 | 1 | 1 | 1 | |
| Methyl Chloride | 1 | 1 | 1 | 1 | 1 | B |
| Methylene Chloride | 1 | 1 | 1 | 1 | 1 | |
| Methyl Ethyl Ketone (MEK) | 1 | 1 | 1 | 1 | 1 | |
| | | | | | | |
| Methyl Formate | 1 | 1 | 1 | 1 | 1 | B |
| Methyl Isobutyl Ketone | 1 | 1 | 1 | 1 | 1 | |
| Methyl Methacrylate | 1 | 1 | 1 | 1 | 1 | |
| Milk | 1 | 3 | 1 | 1 | 3 | |
| | | | | | | |
| Mineral Oil | 1 | 1 | 1 | 1 | 1 | |
| Monochlorobenzene | 1 | 1 | 1 | 1 | 1 | |
