On the seafloor drilling activities can disrupt temperatures and pressures. Large amounts of methane gas trapped in icy sediments may be released causing the sediment around the well to become unstable and collapse. Hydrates are another hazard. These chemicals can become solid when oil is exposed to high pressure and cold temperatures. This can clog well pipes. The chemical properties of oil also make it a dangerous substance. Crude oil and petroleum products contain volatile organic compounds VOCs. Many of the VOCs in oil have a low flash point. The flash point is the temperature at which a substance creates enough vapour in the air that the substance can burn.