1.   Blue flames were running up and down the wires, and blobs of melted plastic insulation were dripping down.

2.   It is as vital as the plastic insulation in a telephone exchange.

3.   First, whittle away the plastic insulation on the outside.

4.   Official explanations for the poisoning range from excessive amounts of nitrates presumably used in fertilizer to poisonous fumes released by scavengers burning plastic insulation off copper cables.