Because of farm fertilizer runoff, the seaweed in coastal waters in Brittany is growing like a monster. Scientists warn that as the seaweed rots, it forms white crust that traps hydrogen sulphide gas. When the crust breaks, it can poison people.
Alain Menesguen, director of research at the French Institute for Sea Research and Exploitation, said: "This is a very toxic gas, which smells like rotten eggs. It attacks the respiratory system and can kill a man or an animal in minutes." Some scientists believe that a build-up of hydrogen sulphide in the atmosphere wiped out the dinosaurs 300 million years ago.
Fumes from rotting seaweed on France's northern beaches could kill
