ECU has an issue with arsenic in some of it's gold ore only and it's never been referred to as dangerous. The Chinese mine being referenced has a high arsenic problem throughout plus carbon bonding. Arsenic is very common with gold in many mines. There are lots of ways to deal with arsenic but everyone wants the most economical. The gold concentrate can also be sold with the arsenic but this will create smelter penalties for the gold con and reduce the return on this concentrate.