title: Chemical and physical characteristics of cellulose insulation particulates, and evaluation of potential acute pulmonary toxicity.
abstract: BACKGROUND
  During installation of cellulose insulation (CI) in new and older houses, significant quantities of airborne material are generated. This study characterized the chemical and physical properties, and potential acute pulmonary toxicity of CI.
  
  
  METHODS
  CI from four manufacturers was analyzed for inorganic additives and trace element impurities. Aerosols were generated and size fractionated. The number and size of fibrous and nonfibrous particles in the respirable fractions were determined. Respirable CI particulates were intratracheally instilled in rats (5 mg/kg) to evaluate potential pulmonary toxicity.
  
  
  RESULTS
  CI samples were similar in composition with small differences due primarily to fire retardants. Less than 0.1% of CI was respirable and contained few fibers. Acute exposure to CI caused transient inflammation in the lungs and increased 4-hydroxyproline. Microscopic evaluation revealed a minimal to mild, non-progressing granulomatous pneumonitis.
  
  
  CONCLUSIONS
  Low concentrations of respirable particles were found in CI aerosols. Particles consisted primarily of fire retardants with few fibers, and caused mild pulmonary toxicity in rats.
authors.affiliation: National Institute of Environmental Health Sciences and the National Toxicology Program, Research Triangle Park, North Carolina 27709, USA. morgand@niehs.nih.gov
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Morgan
authors.forename: Yin-Fong
authors.initials: YF
authors.lastname: Su
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Dill
authors.forename: John C
authors.initials: JC
authors.lastname: Turnier
authors.forename: R Bruce
authors.initials: RB
authors.lastname: Westerberg
authors.forename: Cynthia S
authors.initials: CS
authors.lastname: Smith
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols / Q000633:toxicity; D000395:Air Pollutants, Occupational / Q000032:analysis; D000818:Animals; D001707:Biopsy, Needle; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry*; D002482:Cellulose / Q000494:pharmacology* / Q000633:toxicity*; D003252:Construction Materials / Q000633:toxicity*; D004195:Disease Models, Animal; D005069:Evaluation Studies as Topic; D007150:Immunohistochemistry; D008168:Lung / Q000473:pathology* / Q000648:ultrastructure; D008171:Lung Diseases / Q000139:chemically induced* / Q000473:pathology; D008297:Male; D008422:Materials Testing; D019016:Mineral Fibers / Q000633:toxicity; D010316:Particle Size; D011336:Probability; D051381:Rats; D011916:Rats, Inbred F344; D012307:Risk Factors; D012680:Sensitivity and Specificity; D020711:Threshold Limit Values
chemical_list: D000336:Aerosols; D000395:Air Pollutants, Occupational; D019016:Mineral Fibers; D002482:Cellulose