Shares of Arconic dropped more than 6 percent in early trading on Monday after Reuters reported the U.S. company formerly called Alcoa knowingly supplied flammable panels for use at London's Grenfell Tower.
Reuters said six emails sent to and by an Arconic manager raised questions about why the company supplied the combustible panels despite a public warning that they posed a risk.
Grenfell Tower, which is more than 200 feet tall, was badly damaged in a June 14 fire that killed at least 79 people. London police said Friday the fire started after an appliance malfunction, adding they were considering manslaughter charges over the disaster.
Arconic, a former Dow Jones industrial index component, told CNBC in a statement that it is discontinuing the sales of the panels around the world.
"We believe this is the right decision because of the inconsistency of building codes across the world and issues that have arisen in the wake of the Grenfell Tower tragedy regarding code compliance of cladding systems in the context of buildings' overall designs," the company said in a statement.
It had also told Reuters in a statement it's not up to the company to decide what's compliant with local building regulations.
Shares of Arconic had been on a tear entering Monday's session, rising 37.8 percent for the year.
—CNBC's Morgan Brennan contributed to this report.