What Endpoints Should We Be Using for Materials Components?

As Marty Mulvihill opined in his October 14, 2013 blog, ideally “a perfect building material . . . from raw material sourcing, to building, and through decommissioning – are all safe for human health and the environment.” Chemical risk is a function of both a chemical’s toxicity and an individual’s exposure to that chemical. Therefore it is important to understand not only the toxicity of a chemical, but also the potential route and quantity of exposure during use. The potential exposure routes vary based on the stage of lifetime of use; consequently, the endpoints of concern of exposure may change over the material use lifetime. During manufacture, occupational exposure to humans is primarily via dermal or inhalation exposure. OSHA monitors the exposure levels to the workers producing the materials; however, selection of non-toxic or the least toxic components should minimize these exposures. Toxicity is the appropriate endpoint for manufacturing environmental exposures, which may occur through multiple paths such as spillage or emissions release. The use of the Red List and other green chemistry hazard lists are particularly applicable to chemicals substitution schemes at the manufacturing materials state.

“Once a building is constructed and occupied, inhalation resulting in sensory irritation is the primary exposure route and human response for the majority of chemicals so that sensory irritation potential needs to be considered as a determining important endpoint for chemicals selection.”

However, once a building is constructed and occupied, inhalation resulting in sensory irritation is the primary exposure route and human response for the majority of chemicals so that sensory irritation potential needs to be considered as a determining important endpoint for chemicals selection. This means that volatility of the chemicals, both volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) needs to be considered in determining chemicals of concern as well as their sensory irritation potential. There is the possibility from some materials for particulate matter release that may result in dermal as well as inhalation exposure. Odor may be the most important trigger for indoor air complaints from a product and can be the initiator for sensory irritation and respiratory distress particularly among asthmatics. In most instances, exposures in the built environment will not reach the level of toxicity, but may reach the level of sensory irritation. This may be manifested by different symptoms of sick building syndrome (SBS), such as eye irritation, headaches, asthma exacerbation, stuffy nose, coughing, etc. Odor thresholds of several VOCs at levels commonly found in office environments are low enough, particularly in combination of the generally encountered indoor mixtures, to cause a variety of SBS sensory irritation effects.

As we better understand the endpoints important for exposure risks based on materials lifetimes, more effective and protective data for minimizing exposures as the result of usage of materials should be possible. More effective and targeted materials transparency component information may be possible. The most appropriate endpoints at all stages of lifecycle for a material need to be explored. Over the next year, I will continue to collect and write about the research and data on endpoints, materials, and the components and health and environmental impacts. Through increased knowledge, we will be able to better target the endpoints for materials selection and transparency programs.