Swiss commodity traders accused of deliberately blending toxic fuel and dumping it in West Africa are blaming African governments for failing to invest in refineries and newer vehicles to lower exhaust emissions that cause respiratory and other diseases.

The Geneva-based African Refiners Association representing many traders says "the role of improving fuel quality in Africa clearly rests with African governments, not with the fuel suppliers."

It was responding to allegations from Swiss watchdog Public Eye accusing traders of deliberately adding toxic products that lower fuel quality to increase profits at the expense of Africans' health.

Public Eye said traders including Vitol and Trafigura provide Europe with fuel that has 10 parts per million of sulfur while creating what's called "African Quality" fuel that has 2,000 ppm or more of sulfur.