sentence: Thallium can be a pollutant if the thallium waste from metal processing is washed away.
sentences_before: Thallium is very toxic. It can be absorbed through skin. Many of its salts easily dissolve. Some are colorless, tasteless, and odorless, but are very toxic. Some think that it is a carcinogen.
concept_name: thallium
headings: Thallium Safety
categories: Chemical elements Metals