| 556 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
| * | DD | ORGANIC COMPOUNDS (Class 532, Subclass 1) {3} |
| 1 | DF | .~ HEAVY METAL CONTAINING (e.g., Ga, In or T1, etc.) {19} |
| 2 | DF | .~.~ With preservative or stabilizer {2} |
| 3 | DF | .~.~.~ Compound preserved or stabilized contains lead bonded directly to carbon {2} |
| 4 | | .~.~.~.~ Halogen containing preservative or stabilizer |