London (CNN Business)The world’s biggest metal exchange is changing its rules to combat child labor, money laundering, bribery and corruption.

The London Metal Exchange will require producers that operate in high-risk and conflict zones to demonstrate that their products are responsibly sourced by 2022.
It’s a major policy shift for the 142-year-old exchange, which until now certified metals for trade only by evaluating qualities such as their shape, weight and chemical composition. Now it’s trying to ensure that the metal that ends up in cars or electronic devices is ethically sourced.