The owner of the condemned French aircraft carrier Clemenceau has challenged the environmental group Green peace to prove its claims of level of asbestos in that ship. The ship is on its way to the Alang ship-breaking yard in Gujarat and is expected to fetch more than 27000 tons of steel. He said that no laborer has displayed symptoms from asbestos in Gujarat and the safety of employees is given due importance. Asbestos is a carcinogenic substance banned in most of the developed world but used extensively in the developing world, including India. The effects of exposure to asbestos are seen only after 15 years and its carcinogenic effects are well documented. The Supreme Court has required Clemenceau to stay out its exclusive economic zone till it produces a verdict on February 12.