NATO ally Turkey has accused Washington of waging an "economic war" as part of a plot to harm the country.
Scientists are exploring whether agricultural pollution might be playing a role in Florida's red tide, which is killing sea life and making people sick.
Many victims "ran out of time to sue before they even knew they had a case," the Pennsylvania grand jury said.
"It will never go back to how it was. It just won't," said Andrea Peña, 16, a junior.
Beijing is increasingly focused on environmental issues — a marked shift from its traditional growth-at-all-costs philosophy.