More than 500 species of plants have disappeared in the past 250 years. Stock photograph: Reuters

More than 570 plant species have disappeared in the past 250 years - twice the number of birds, mammals and amphibians recorded as extinct, a new stud(...)

The incident occurred at a facility known as PUREX, located in the middle of the sprawling Hanford nuclear site,  an official said. File photograph: Getty Images

A tunnel partly collapsed on Tuesday at a plutonium-handling facility at the Hanford Nuclear Reservation in Washington state, but there was no indicat(...)