Balsam Wool Insulation was sold in the early part of the 20th century. Balsam Wool Insulation was made from the following:
1. Wood Fiber
2. Liquid Fire Retardant impregnated into fiber (borax-based)
3. Asphaltic binder to maintain loft
4. Kraft paper backing
A dust mask is recommended for the wood dust and fine particulates if the insulation is to be removed/disturbed
Note: Weyerhaeuser Balsam Wool Insulation does not and never has contained asbestos fibers.