In and Near Fresh Water. Creosote treated wood has been a building material of choice for many years where protection against decay and rot is required. It is effective against marine borers. Before the development of newer products, creosote treated wood, which was first patented in 1838, was used whenever long term durability was required, Creosote is a distillate of coal tar. It contains over 160 compounds but is composed primarily of liquid and solid aromatic hydrocarbons as well as some tar acids and tar bases which provide protection against destructive insects and organisms.
Creosote contains impurities that are toxic, carcinogenic and mutagenic.
Leaching and weeping of creosote, especially in hot weather is a particular problem. There are various industry guidelines that deal with the manufacture, handling and use of creosote treated woods. The recent abandonment of the CN Railway has brought to market a large supply of used, but serviceable creosote treated wood. This wood is often being used by uninformed people for a variety of domestic projects such as retaining walls, shed foundations, wharves, bridges and walkways. Presently there are no regulations that deal with the use of any treated woods in connection with water resources.