Shares fell as much as 13% after the miner and commodities trader was told by US Department of Justice to produce documents on Nigeria, Congo and Venezuela.
China's top steel maker China Baowu Steel Groups move is in line with Beijing's goal push to relocate heavy industries from polluted and crowded regions to places with less environmental pressure.
It is not the first time Chinalco, China's biggest state-owned aluminium producer, has run afoul of the country's ever stricter environmental regulations.
Teneris will lay off 40 workers at its TenarisAlgomaTubes plant in Ontario and adjust output there because of the U.S. tariffs on steel and aluminum imports.