To reduce indoor air emissions, wastes, and other environmental impacts associated with construction adhesives and sealants, consider:

Stains and Sealants

• Consider materials that require no sealants, eliminating this source of indoor volatile organic compound (VOC) emissions.
• Petroleum-derived solvents, particularly products containing chlorinated hydrocarbons, are a serious concern for interior applications. (If you’re not a chemist, find substitutes for products with ingredients or warnings containing the prefix ‘chlor-‘, or the word ‘chloride.’ For example, trichloroethylene and methylene chloride are found in many adhesives, while perchloroethylene is found in some sealants. All three chemicals are probable human carcinogens.)  
• Architectural details, such as eaves and flashing, can help minimize sealant requirements.
• For low-traffic areas, consider using stains without additional sealants.
• Consider plant-based, non-toxic, or low-toxicity sealant formulations.

Adhesives

• Consider water-based low- or zero-VOC construction adhesives. There are several cost-effective options tested to meet appropriate ASTM and APA performance standards.
• Consider whether an adhesive is necessary for the application – materials joined by nails, screws, and other appropriate fasteners are more readily deconstructed for recycling, while adhesives distribute loads over larger areas rather than concentrating them at fasteners.
• Purchase adhesives in bulk, which is cheaper and eliminates disposal of empty tubes with potentially hazardous residue.

For adhesives, stains, and sealants that are not water-based:

• Purchase only the amount needed.
• The Santa Cruz County Second Chance Store sorts and distributes leftover household hazardous materials for free. Call (831) 454-2606 for information.
• Dispose of the remainder and containers properly.
  Call (831) 454-2606 for information about free household hazardous waste disposal in Santa Cruz County, or click www.dpw.co.santa-cruz.ca.us/hazwaste.htm.

Summary: Adhesives and Sealants

Sealants enhance the resistance of materials to water or other chemical exposure, while caulks and other adhesives can help control vibration and strengthen assemblies by spreading loads beyond the immediate vicinity of fasteners. Both properties enhance durability of surfaces and structures, but at a cost - these products are generally hazardous in manufacture and application. Many construction adhesives formulas contain more than 30% volatile petroleum-derived solvents, such as hexane, to maintain liquidity until application. Not only are workers exposed to toxic solvents, the materials continue to outgas during curing, potentially exposing occupants to such emissions for extended periods. Some common adhesive formulations are a greater source of VOC emissions than the flooring and other materials they hold in place.

Water-based adhesives are available from a number of different manufacturers. (See the links at the end of this sheet.) Industry tests indicate that these products work as well as or better than solvent-based adhesives, and pass all relevant ASTM and APA performance tests. In addition, water-based and low VOC products containing little or no solvent have comparable costs to common solvent-based adhesives. When adhesives are purchased in bulk, larger containers can often be returned to vendors for refill. A pump or other tools are required to distribute the material, but the disposal of caulk tubes containing potentially hazardous material is eliminated.

Stains and sealants also commonly emit potentially toxic VOC's into indoor air. The simplest way to manage this problem is to use materials that do not require additional sealing, such as stone, ceramic and glass tile, and clay plasters. The toxicity, and the air and water pollution generated in the manufacture of chlorinated hydrocarbons such as methylene chloride, argues strongly for the use of responsible, effective alternatives, such as plant-based, non-toxic, or low-toxicity sealant formulations.

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