Analyze the relationship between 'smelting' and 'metal' within the context of the input sentence.
Options: product/material produced, publisher, director/manager, distributed by

Keller Rohrback has also handled environmental litigation involving home heating oil, contaminated drinking water, contaminated sediments, landfill leachate, metal smelting and finishing wastes, tank farms, chemical plants, gas stations, and major manufacturing concerns.
product/material produced