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The Molasses Flood of 1919 and Other Ethical Failures in Engineering

Mark P. Rossow, PhD, PE Retired

Course Outline

This two-hour online course begins with a discussion of the legal definition of “negligence” and the closely related notion of the “standard of care” expected of an engineer.  Because the occurrence of serious accidents always raises questions of whether adequate safety precautions had been taken, the relation between safety and risk is discussed.  Similarly, since a serious accident usually results in a failure investigation, the biases often inherent in such an investigation are described, as are the use and misuse of investigation reports by persons who differ widely in their motives.  Finally these concepts are illustrated with a description of the Great Boston Molasses Flood of 1919, and four additional case studies.

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.

Learning Objective

This course teaches the following specific knowledge and skills:

Intended Audience

This course is intended for engineers concerned with ethical behavior in engineering practice.

Benefit to Attendees

A person completing this course will be familiar with and able to distinguish negligence in engineering practice.

Course Introduction

Consider the following situation.  An engineering firm designs a device, the device subsequently fails, and as a result several people are injured or killed.  This situation clearly involves an engineering failure—the device did not do what it was supposed to do—but was the engineer negligent in his duties to protect the public?  Deciding if an engineer has been negligent can be difficult.

Course Content

This course is based on the paper, “The Molasses Flood of 1919 and Other Ethical Failures in Engineering,” written by Mark P. Rossow, July, 2015.

The Molasses Flood of 1919 and Other Ethical Failures in Engineering

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Course Summary

Negligence in engineering can be recognized if the standard of care followed by a prudent engineer can be defined.  Notions of safety, risk, investigation bias, punishment and blame all may influence what observers of an engineering failure choose to define as negligence.

Related Links

For additional technical information related to this subject, please visit the following websites or web pages:


Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.