Amazon sold the food preservative sodium nitrite, which lawyers say has no household use at high purity levels, to people who later killed themselves using the substance, the suit claims.

A U.S. judge has dismissed a lawsuit against Amazon.com Inc brought by the parents of two teenagers who committed suicide by consuming sodium nitrite they bought on the online retailer's platform.

The preservative, sodium nitrite, is primarily used - in a diluted form - by meat processing companies. But in recent years, it has also been increasingly used - in its pure form - as a suicide agent.