Methemoglobinemia Resulting from Work in an MDI Tank Webinar Recording

Date: Thursday, Aug. 26, 2021 - Thursday, Aug. 26, 2021
Time: 1:00 p.m. - 2:30 p.m. (EDT)
Event Type: Webinars, AIHA Webinars

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Earn 1.5 Contact Hours

Member $140 | Nonmember $175 | Student $25

Seemingly hardened, fully reacted 4,4 methylene diphenyl diisocyanate (MDI) solid waste material can form various hazardous exothermic compounds including aniline and p-toluidine. These compounds have skin designations and can cause exposure by penetrating the unprotected and unbroken skin.

This webinar will discuss a near-fatal exposure that occurred while cleaning a tank with hardened isocyanate waste material. You will learn more about the hazards of MDI, aniline, and p-toluidine, what methemoglobinemia is, and the impact on the body.

The accident outlined in this case study occurred to an experienced company that specializes in clean-up activities, and they did not realize that anything more than a 4-gas direct reading instrument was needed to keep their workers safe while cleaning up this solid material.

This case demonstrates the need to share lessons learned from this accident with the broad occupational safety and health community.

Who Will Benefit

All levels of occupational health and safety professionals will be able to learn from this presentation as isocyanates are widely used in many industries.

Learning Objectives  

  • Identify potential decomposition products of 4,4 methylene diphenyl diisocyanate (MDI) from an exothermic reaction including aniline and p-toluidine
  • Inform attendees on how MDI decomposition products are identified through various analysis methods
  • Discuss the hazards of MDI, aniline, and p-toluidine
  • Describe what methemoglobinemia is, how it affects the body, and what MDI exothermic decomposition products can cause methemoglobinemia


Phil Smith, CIH, received a BS degree in zoology from Brigham Young University in 1984, and an MPH degree from the University of California, Berkeley in 1987. In 1987 he was commissioned in the U.S. Navy Medical Service Corps as an industrial hygiene officer, where he continued to serve on active duty for more than 23 years. While on active duty, he was selected to complete additional full‐time graduate education training and completed the requirements for a PhD degree in toxicology at Utah State University in 1998. Following this, Phil was assigned as a faculty member at the Uniformed Services University of the Health Sciences in the Department of Preventive Medicine and Biometrics, eventually attaining the academic rank of associate professor. From 2010 to 2016 he was a member of the OSHA Health Response Team, supporting OSHA field activities nationwide with expertise in solving complex industrial hygiene exposure assessment problems.

Since 2016 he has been the Director of the OSHA Analytical Chemistry Laboratory located at the Salt Lake Technical Center. Phil has published over 50 book chapters and peer‐reviewed publications in the areas of chemical identification in complex mixtures, the development of tools and methods for chemical detection, and the application of those tools and methods to solve exposure assessment problems. His primary research focus is on the use of field‐portable detection and identification systems that are fast, small, and that provide high-quality information, such as portable gas chromatography‐mass spectrometry instruments. Since 1993 Phil has been board certified by the American Board of Industrial Hygiene in the comprehensive practice of industrial hygiene.


Contact [email protected].