3,5,6-TRICHLORO-2-PYRIDINOL 3,5,6-Trichloro-2(1H)-pyridinone 3,5,6-Trichloro-2-pyridone 37439-34-2 6515-38-4 Caswell No. 821AA EINECS 229-405-2 EPA Pesticide Chemical Code 206900 TCP