A Malaysian court lifted the suspension Thursday of an Australian mining company mining for rare earth after fears of radioactive hazards were allayed. Some, though, fear there is still a risk.

Lynas will start production at an $800 million plant in the eastern Malaysian state of Pahang – one of the few sites to process rare earth outside China. An appeal by activists over fears that it would release radioactive gases and solid waste was heard in court but has now been dismissed.

“This is the darkest day in our lives,” Tan Bun Tet, head of environmental group Save Malaysia Stop Lynas, told AFP, adding that the group would appeal against Thursday’s ruling.

Environmentalists claimed that hazardous waste from the plant processing rare earth, which is used in high-tech equipment such as missiles and mobile phones, could seep into ground and water, harming both the environment and human health.

The Australian firm claimed that the plant is safe and that radioactive waste would not be harmful.