Inhalation health effects testing of isobutanol gasoline blend: a promising new biofuel

Details

• Personal Author:
  Baustian J ; Burnett D ; Hoffman G ; O'Callaghan J ; Parker R
• Description:
  Isobutanol is a high-value molecule offering several advantages over existing transportation biofuels. Isobutanol blended with gasoline at 16% is currently under development as a new automotive biofuel in the US. To evaluate the potential health effects from exposure to isobutanol gasoline blend when dispensed at the pump, a battery of GLP whole-body inhalation studies using Sprague-Dawley rats was conducted in accordance with US EPA fuel testing requirements, described in Section 211(b) of the Clean Air Act and its Alternative Tier 2 Rule. Testing included the following guideline studies: 90-day subchronic toxicity with neurotoxicity, neuropathology, glial fibrillary acidic protein (GFAP) measurements across 8 brain regions, and 4-weeks recovery; 28-day immunotoxicity; 28-day genotoxicity; one-generation reproductive toxicity; and embryo-fetal developmental toxicity. To approximate the hydrocarbon composition of fugitive emissions to which humans are potentially exposed during refuelling, light-end hydrocarbon emissions were generated from the whole fuel heated to 130 degrees F and condensed to form a vapor condensate (VC) test substance. Isobutanol levels in the VC were 2-3%. In all studies rats were exposed to re-vaporized test substance at target concentrations of 0 (air control); 2,000; 10,000; and 20,000 mg/m3, the latter being 50% of the lower explosive limit of the VC. Exposure frequency and duration were tailored to study design. The only treatment-related finding in the 90-day study was light hydrocarbon nephropathy in male rats, a known effect specific to male rats and not relevant to humans. No treatment-related findings were seen in neuropathology, GFAP, neurotoxicity, immunotoxicity, genotoxicity, or developmental toxicity. The no-observed-adverse-effect level (NOAEL) for these endpoints was 20,000 mg/m3. In the reproductive study transient changes in body weight gain and food consumption were seen in high-dose paternal and maternal animals. These effects occurred at hydrocarbon exposure levels several orders of magnitude above conditions typically experienced at dispensing pumps during refueling (<1 mg/m3, 5 min). Based on these results, inhalation exposure to light-end hydrocarbons emitted from 16% isobutanol gasoline during refueling is unlikely to present a unique health hazard to humans. [Description provided by NIOSH]
• Subjects:
  Acids Chemistry Environmental Exposure Fetus Fuel Oils Hydrocarbons Kidney Diseases Laboratories Nervous System Occupational Health Respiratory System Safety Solvents Toxicology Urogenital Diseases Urogenital System

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• Keywords:
  Acidity Biological Effects Brain Function Chemical Processing Developmental Disorders Embryotoxicity Environmental Technology Exposure Assessment Exposure Levels Fuels Gasoline Genotoxicity Health Effects Immunotoxins Inhalation Studies Isobutyl Alcohol Laboratory Animals Laboratory Testing Nephrotoxicity Neuropathology Neurotoxicity Proteins Regulations Reproductive Effects Vapors

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• ISSN:
  1096-6080
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  Delaware ; Illinois ; Louisiana ; New Jersey ; OSHA Region 2 ; OSHA Region 3 ; OSHA Region 5 ; OSHA Region 6 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  150
• Issue:
  1
• NIOSHTIC Number:
  nn:20047693
• Citation:
  Toxicologist 2016 Mar; 150(1):345
• CAS Registry Number:
  Isobutanol (CAS RN 78-83-1)
• Federal Fiscal Year:
  2016
• Peer Reviewed:
  False
• Source Full Name:
  The Toxicologist. Society of Toxicology 55th Annual Meeting and ToxExpo, March 13-17, 2016, New Orleans, Louisiana
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:ce5d8713a2bdbc3c4a1a9e4b563b8e4e1b3dd3ee146519095547874195e2a0e11993d1ac83fb7b4f36b315333d08dd890e142717d1419f4c6c235c20265c2b28
• Download URL:
  https://stacks.cdc.gov/view/cdc/202696/cdc_202696_DS1.pdf
• File Type:
  [PDF - 441.58 KB ]