Technical Note Inventory of Nanomaterials in Construction Products for Safety and Health Ahmed Jalil Al-Bayati, Ph.D., P.E., M.ASCE 1 ; and Hazim A. Al-Zubaidi 2 Abstract: Construction workers face the possibility of exposure to nanomaterials, which are particles smaller than asbestos. Nanomaterials exposure is expected to increase in coming years because of the advantages and desirable characteristics of nanoconstruction products. The lack of knowledge and preparedness in the construction industry for this technology is apparent. There are few research studies in the United States that have evaluated the potential safety and health risks of construction nanomaterials on the construction workforce. The Center for Construction Research and Training (CPWR) has built a database containing more than 400 construction products in the United States that may contain nanomaterials. This paper investigates the nature of the nanoparticles in these construction products. Additionally, a sample of the possible safety and health hazards affecting construction workers is provided. The findings confirm the industry’ s lack of preparedness regarding the potential risks of construction nanomaterials, which may create or exacerbate unsafe conditions. Finally, the paper points out the necessity of communicating the potential hazards of nanoparticles to the construction workforce in contact with these products. DOI: 10.1061/(ASCE)CO.1943-7862.0001547. © 2018 American Society of Civil Engineers. Introduction Nanotechnology has garnered a great deal of attention in the last two decades in almost all fields. Outstanding and unique chemical and physical properties are reported for nanoscale materials when compared with their bulk-scale counterparts (Lee et al. 2010). These unique properties could improve a product in a way that is not feasible otherwise (ISO 2017). Accordingly, nanomaterials have become an essential technology for various fields such as medicine, pharmaceutical, material, environment, and construction (Sharma et al. 2015). Nanomaterials as additives can boost con- struction material properties in positive ways such as strength, workability, and lightness (West et al. 2016). Therefore, various nanomaterials such as carbon, metal oxides, and metals have been used in construction materials (Lee et al. 2010). Nanoscale materials have physical dimensions between 1 and 100 nm (1 nm ¼ 10 -9 m). Per ISO (2017), nanomaterials are ma- terials that have internal structure or surface structure in the nano- scale. Also, a nano-object is a discrete piece of material that can be classified based on its dimensions to (1) nanoparticle (i.e., three dimensions in nanoscale), (2) nanofiber including nanotube (i.e., two dimensions in nanoscale), and (3) nanoplates (i.e., one dimension in nanoscale). A solid mixture that contains two or more separated ingredients such as concrete could be called a nanocom- posite material if one (or more) of its ingredients is a nano-object (ISO 2017). Due to their small size and high surface area to volume ratio, nanomaterials are considered highly reactive materials. As a result, various chemical and biological transformations could occur to nanomaterials at construction sites, including bioreactions, redox reactions, aggregation, and dissolution. Nanomaterials can be haz- ardous to both environmental and biological systems; however, their exact influence is still ambiguous because of their novel prop- erties (Beaudrie et al. 2015). Furthermore, the various applications of nanomaterials make it difficult to monitor their impact (Lowry et al. 2012). Historically, novel material applications in the construction industry such as asbestos and lead have resulted in undesirable consequences (West et al. 2016). Similar conse- quences are expected to continue to occur on construction sites. In particular, according to the CPWR (2013), the probability of exposure to dust for construction workers is much more than in all other industries. The interaction between nanomaterials and construction workers’ biological systems can be classified in a range from safe to unsafe, as defined by the nanomaterials’ release status. Under normal working conditions, safe nanomaterials do not release or interact with workers or the construction environment [i.e., nonre- leasable nanomaterials (NRNs)], for example, tissue engineered materials in fire resistance suits (Alongi and Malucelli 2015). On the other hand, unsafe nanomaterials do release and interact with workers or the construction environment [i.e., releasable nano- materials (RNs)]. Table 1 illustrates examples of RNs that may pose hazards on workers’ biological systems (Meng et al. 2009). Table 1 also shows the possible existence of RNs in construction sites to enhance the quality and performance of construction materials without considering their possible undesirable health effects. Exposure to nanomaterials can occur during the manufacturing and packaging of construction materials, the construction phase, or the operation phase. For example, a study conducted by DuPont (2007) showed that workers’ exposure to titanium dioxide in the packaging process exceeded the recommended exposure limit. As another example, construction nanomaterials can be transformed into new forms when manufactured on a large scale (Johnson et al. 2010). Additionally, Johnson et al. (2010) found that carbon-based nanomaterials can be converted into airborne nanomaterials when prepared as a solution. However, while characteristics of construc- tion nanomaterials may increase toxicity hazards for construction 1 Occupational Safety and Health Administration (OSHA) Authorized Trainer and Assistant Professor, Kimmel School of Construction Management, Western Carolina Univ., 225 Belk, Cullowhee, NC 28723 (corresponding author). ORCID: https://orcid.org/0000-0002-0244-0638. Email: ajalbayati@wcu.edu 2 Ph.D. Candidate, Dept. of Chemistry, Western Michigan Univ., 3438 Wood Hall, Kalamazoo, MI 49008. Email: hazimabdulrazz.alzubaidi@ wmich.edu Note. This manuscript was submitted on October 20, 2017; approved on April 9, 2018; published online on June 30, 2018. Discussion period open until November 30, 2018; separate discussions must be submitted for in- dividual papers. This technical note is part of the Journal of Construction Engineering and Management, © ASCE, ISSN 0733-9364. © ASCE 06018004-1 J. Constr. Eng. Manage. J. Constr. Eng. 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