A huge blaze at a Vale of Glamorgan industrial estate that burned for more than two weeks started accidentally, investigators say.
The fire at Siteserv on the Vale Business Park in Llandow could be seen across the Bristol channel when it broke out on 26 November.
Almost 90 firefighters tackled the blaze of recycled material.
South Wales Fire and Rescue Service said no charges were to be brought and it considered the matter closed.
It was the second fire in less than a month after another Siteserv building nearby was accidentally destroyed.