Timbor Professional granular wood preservative is often used as an internal treatment to fill the physical voids that can occur in standing utility poles. Dilute this EPA registered wood preservative with water before use. Insect attack, decay and other physical activities can cause strength reducing voids in poles. Traditional injection of Copper Naphthenate is still a common practice, but borates offer a less toxic alternative. Timbor Professional can also be used to treat many types of wood that will be installed in above ground applications. Decks, log homes, fence pickets and other wood products are commonly treated with borates. Always read and follow EPA label directions.