Forensic Engineering Investigation of a Machine Guarding-Related Injury


  • Jason McPherson



OSHA, ANSI B11, Machine Guarding, Forensic Engineering, Standards, Safeguard, Point of Operation, Normative Reference, NFPA 79


OSHA regulations and industry-accepted standards are intended to be used in conjunction to help prevent worker injury. Despite the aforementioned intention, a point of operation injury occurred to an employee while he was operating a hydraulic rotary bending machine. The machine had been retrofitted with a two-hand control device that was intended to act as a means of point of operation safeguarding. A forensic engineering analysis of both the electromechanical design and programmable logic code — combined with a performance and prescriptive requirement analysis — ultimately revealed flaws in the design of the electromechanical system and software design. It also demonstrated a lack of adherence to the applicable industry-accepted standards related to machine guarding. These factors led to the point of operation injury.


OSHA. (2021). Top 10 Most Frequently Cited Standards for Fiscal Year 2021 (Oct. 1, 2020, to Sept. 30, 2021). Available:

C. R. Asfahl and D. W. Rieske, Industrial Safety and Health Management (no. 7th). 330 Hudson Street, NY 10013: Pearson, 2019, p. 515.

General requirements for all machines, OSHA.

Machinery Safety Standards. Available:

B11.0 Safety of Machinery – General Requirements and Risk Assessment, 2010.

B11.15 Safety Requirements for Pipe, Tube, and Shape Bending Machines, 2012.

B11.TR4 ANSI Technical Report for Machine Tools – Selection of Programmable Electronic Systems (PES/PLC) for Machine Tools, 2004.

NFPA 79 Electrical Standard for Industrial Machinery, 2012.

B11.TR6 ANSI Technical Report for Machines – Safety Control Systems for Machine Tools, 2010.

Additional Files



How to Cite

McPherson, Jason. 2024. “Forensic Engineering Investigation of a Machine Guarding-Related Injury”. Journal of the National Academy of Forensic Engineers 40 (2).