A environmental group says Australia’s refusal to ban a toxic pesticide is placing the health of residents and the Great Barrier Reef at risk.

WWF says the decision by the Australian Pesticides and Veterinary Medicines Authority (APVMA) on Wednesday to reduce the levels of diuron which can be used doesn’t go far enough.

Diuron is classified by the US Environmental Protection Agency as a likely carcinogen and has been linked to coral bleaching and the death of seagrass on the Great Barrier Reef, according to WWF.

Spokesman Nick Heath says the pesticide is so toxic, one gram in four Olympic-sized swimming pools would be enough to damage seagrass.

“The APVMA has again failed to protect the Great Barrier Reef,” he said in a statement.

“We call on the minister and the prime minister to intervene and give the APVMA stronger powers and an obligation to ban these dangerous chemicals.”