Occupational and Inhalation Exposures Research Program

National Institute Of Environmental Health Sciences

Investigators

Linked publications, trials & patents

Abstract

According to National Institute for Occupational Safety and Health (NIOSH), fatalities from respiratory diseases and cancers caused by inhalation exposures account for approximately 70% of all occupational disease deaths. Respiratory diseases caused by occupational inhalation exposures include those affecting the large and small airways (such as allergy/asthma and fibrosis), interstitial(fibrotic) lung diseases (such as silicosis/asbestosis), pleural disease, and lung cancers. These adverse respiratory tract effects can be linked to acute or chronic (high- or low-dose) inhalation exposures in a wide variety of workplace settings and range from mild, reversible conditions to progressive, irreversible fatal disorders. Inhalation exposures can also cause adverse health effects in other (non-respiratory) organ systems. Inhalation exposures to toxic compounds tend to be weighted to occupational settings, although the general public may also be exposed to similar hazards via inhalation in the environment. However, inhalation exposures in the workplace tend to be at relatively higher doses compared with chronic, low-dose exposures to the general public. Other potential (non-inhalation) routes of exposure exist in the workplace (e.g., dermal sensitization) and for the general public (e.g., radiation) that can also cause adverse health effects to the respiratory tract and other organ systems. In alignment with NTP goals, the OIE Program provides trusted science to support decision-making. Results from hazard characterization studies are utilized to ensure risks related to exposures are mitigated. In addition, this program actively engages stakeholders and subject matter experts, in coordination across the Division of Translational Toxicology (DTT) (other programs) and the National Institute of Environmental Health Sciences (NIEHS), to enhance the goal of developing and applying innovative tools and strategies for addressing occupational/inhalation toxicology. This program also examines current in-house approaches and processes to enhance our ability to detect translatable toxicological responses more effectively and efficiently. Research supported by the OIE Program this last year has resulted in the publication (Wang et al., 2023 Part A; Wang et al., 2023 Part B) of method development work to support toxicity studies of natural mineral fibers (e.g., Libby Amphibole) and the initiation of chronic studies to assess the carcinogenic potential of these fibers following nose-only inhalation exposure. Additionally, DTT completed the reporting of the inhalation toxicity studies of two volatile artificial butter flavoring components, acetoin and 2,3-pentanedione, following nose-only inhalation exposure which was published as a NTP Toxicity Report (TOX-98) and presented as part of a poster at the Society of Toxicology annual conference in March 2023. Method development/validation and protocol optimization were also continued for in vitro studies evaluating the inhalation toxicity of 2,3-pentanedione using human- and rat-derived air-liquid interface (ALI) airway cultures combined with a Vitrocell exposure system. Ongoing exposure assessments of indoor and occupational fungal aerosols, evaluated through an Interagency Agreement (IAA) between DTT and NIOSH, have also been summarized in a publication by Park and colleagues (2022). To compliment this research, we are currently characterizing the pulmonary, immunological, and toxicological hazards associated with fungal aerosol exposure utilizing in vivo animal models. This work, as well as additional ongoing efforts, are focused on understanding the health hazard potential of current/emerging agents of concern to the general public and in the workplace using guideline and alternative/novel in vivo studies, complemented by invitro approaches, with designs tailored to address specific key questions and data needs.