Health hazard evaluation report, HETA 2002-0239-2922, United States Postal Service, Norman, Oklahoma.
On April 29, 2002, the National Institute for Occupational Safety and Health (NIOSH) received a request for a Health Hazard Evaluation (HHE) from the Director of Safety and Health of the National Association of Letter Carriers (NALC) in Washington, D.C. The HHE requesters wanted NIOSH investigators to evaluate whether use of a personal human transporter (HT) to deliver mail presented health hazards or risk of injury to its member. On June 24, 2002, an opening conference took place in Washington, D.C. The meeting was attended by NIOSH investigators and representatives of the United States Postal Service (USPS), the NALC, and the Segway corporation, manufacturer of the HT. During July 15-18, 2002, NIOSH investigators evaluated the HT in Norman, Oklahoma. The NIOSH team included an ergonomics specialist, a noise and vibration specialist, and an epidemiologist with expertise in injury surveillance. The ergonomics evaluation indicated that the HT is designed for and can be adjusted to fit the size range of most mail carriers who would use it. Mail carriers at the far end of the spectrum of height and weight may not be able to comfortably use the HT. The analysis of videotapes taken during the evaluation indicated that improvements to the HT could and should be made, but these would affect the usability and efficiency more than reduce the risk of injury to the worker. The whole-body vibration evaluation indicated that postal employees are exposed to measurable levels of whole- body vibration while using the Segway HT. The greatest weighted and peak acceleration levels were from head- to-toe, which occurred while traveling over bumps in streets, sidewalks, or driveways and travel over lawns. However, since little of the published epidemiological research on vibration effects is specific to people who are exposed to whole-body vibration while standing on a movable vehicle, it could not be determined if the health of the employees would be compromised from the use of the Segway HT. The epidemiology/injury surveillance evaluation indicated that existing accident report forms, if completed and available, contain useful data regarding safety aspects of the HT. If these forms are filled out in detail after accidents occur, no new procedures would be needed to implement a surveillance system for tracking HT accidents during mail delivery. NIOSH investigators conclude that using a HT to deliver mail may result in harmful vibration and jolts to mail carriers but that there is lack of sufficient comparison data or standards to determine the extent of the hazard. The HT can be adjusted to fit most mail carriers, so there should be little additional risk of injury from design aspects. If the HT is used to deliver mail, the USPS should make more vibration measurements and establish a surveillance system for tracking the health status of workers using it. Additional recommendations pertaining to the use of the HT to deliver mail are contained in this report.