SAN FRANCISCO — (AP) — A federal appeals court in San Francisco says the government must revoke its approval of a widely used weed killer that has damaged other crops and turned neighbor against neighbor in some farm communities.

The San Francisco Chronicle says the court ruled Wednesday that the EPA has understated or ignored the risks of dicamba.

The herbicide is used on tens of millions of acres of soybeans and cotton nationwide. But the court said it has caused environmental and economic damage by drifting to nearby fields and killing crops that aren't genetically engineered to tolerate it.