This specification covers the composition and physical requirements of chemically treated, recycled cellulosic fiber loose-fill type thermal insulation for installation in attics or enclosed spaces in housing and other buildings by pneumatic or pouring method. While the products are used in various constructions, they are adaptable primarily, but not exclusively, to wood joists, rafters, and stud constructions. The basic material shall be made from selected paper, paperboard stock, or ground wood stock, excluding contaminated materials, which may reasonably be expected to be retained in the finished product. Suitable chemicals are introduced to provide properties such as flame resistance, processing, and handling characteristics. Products shall be prepared suitably to undergo test methods, for which they should comply with the following physical and chemical property requirements: corrosiveness; critical radiant flux; fungi resistance; moisture vapor sorption; odor emission; smoldering combustion; and thermal resistance.