NYC-WTC_000229683

NYC 9/11 Public Portal Document

'Dust Control Evaluation Summary f October 11, 2001

• Soybean oil. • Adhesives, including lignin derivative, tree resin emulsions, and synthetic polymer emulsions, which bind particles together. • Foams that encapsulate particles with minimum moisture addition.

Chemical dust suppressants are typically applied by mobile and/or stationary equipment, using spray nozzles. Chemical dust suppressants may be applied to roadways, existing debris stock piles, and other work areas. It is likely that different chemical dust suppressants may be appropriate for different application.

ALTERNATIVES COMPARISON

Water and alternative chemical dust suppressants are compared in the following table:

Type of Source Functional Performance Performance Worker Chemical Mechanism Advantages Limitations Exposure Suppressant Considerations Water Surface or Moisture wets Readily available, Frequent Generation of groundwater particles, lowcost, easy to applications may be surface water runoff increasing apply necessary; mass and overapplication may binding them result in loss of together traction, or erosion; freezes below 32 deg F Salts Produced from Attracts and Reduces Effectiveness in and Dermal and natural salt retains evaporation rate and semi-arid inhalation irritant; will brine moisture at of surface regions may be degrade leather relative moisture, lowers limited; corrosive to boots humidity equal freezing point of aluminum alloys; to or greater water; increases slightly corrosive to than 29% compacted steel; solubility density of road results in leaching material; good soil during heavy penetration; short precipitation; curing times releases heat when mixed in water Lignin Paper industry Acts as Increases dry High solubility may Product-specific Derivatives by-product adhesive strength of soil; result in leaching imparts some during heavy pl^icity to road precipitation, surfaces; lowers becomes slippery freezing point of when wet, brittle roadsur^Kie when dry Tree Resin Emulsions from Acts as Low solubility Requires proper Product-specific Emulsions pine tree resins adhesive minimized weather and time to leachii^and cure; no residual provides degree effectiveness after of surface reblading; waterproofing; equipment requires Imparts some prompt cleanup to plasticity; high avoid cunng of resin bonding strength; in hoses and pipes non-corrosive Synthetic Synthetic Binds soil Applicable to a Requires proper Product-specific Polymer formulations particles range of dust weather conditions Emulsions composed of together by emission sources; and time to cure; polyvinyl forming a functions weH in may be subject to acetates, vinyl polymerizing sarxiysoil; UV degradation; acrylic matrix, function increases load- application copolymers, similar to beanng strength equipment requires copolymer adhesives of roadway timely cleaning; no methacrylates. residual

3

NYC-WTC_000229685