Legislation in most advanced industrial countries is demanding more stringent protection of the water table. Chemical spillage and the diffusion of chemicals into the ground, leading to contamination of water, is being strictly controlled. A good example of these regulations is the containment of spillages of gasoline and diesel on gas station forecourts. Previous systems relied on the use of membranes (for example, heavy duty polyethylene sheeting). These are no longer thought to be reliable in the long term and more durable systems have been developed. These consist of fuel impervious concrete, sometimes in the form of hexagonal blocks, with joints sealed with fuel resistant sealants. The long term adhesion of the sealant/primer system to concrete immersed in fuels is one of the more difficult requirements of the specification. Other applications of polysulfide systems in pollution control are described.