Machine Safety: 12 hazards of unused machinery

Look at the 5 levels of hazard mitigation to help determine risk of a machine no longer in use. Consider the following 12 hazards of end-of-lifecyle machines. An unused machine is not necessarily safe.


The safety lifecycle of machinery has received significant attention over the past 10 years, especially how to perform safety mitigation during the design stage of a machine by applying the five levels of hazard mitigation. But at the tail end of the lifecycle, is a machine no longer in use considered safe? Machines at their end of lifecycle are often retired, decommissioned, or simply mothballed in place. 

5 levels of hazard mitigation

Even though a machine may no longer be active in the production process, this does not mean that the machine has been rendered hazard-free according to the five levels of hazard mitigation:

1) Eliminate the hazard - design it out

2) Isolate the hazard with hard guarding

3) Add additional engineering, guards, devices, or layers of safety

4) Implement administrative controls such as training, signage, assessments, etc.

5) Use personal protective equipment (PPE) such as goggles, gloves, outer clothing, shields, etc.

12 hazards to consider for a machine no longer in use

If a risk assessment were to be completed on a decommissioned machine, here are a few examples of potential residual hazards:

  1. Live electrical connections
  2. Compressed gases or fluids
  3. Charged tie rods
  4. Compressed springs
  5. Gravity
  6. Hazardous materials
  7. Rust
  8. Flammable or combustible material
  9. Abandoned conduit as a route for hazardous vapors
  10. Leakage
  11. Blocking of emergency access
  12. Other machine, application, or environmental considerations.

These examples of residual hazards can also create conditions that result in fires, explosions, and hazardous material (hazmat) exposures. It has been my experience that decommissioned, out-of-service machines that stay in place also require a comprehensive risk assessment program. All risks associated with these machines must be identified and all measures to mitigate those risks must be implemented so as to reduce those risks to acceptable levels.

This process is, therefore, no different than when the machine was first installed for commissioning and production.

Any questions or challenges with end-of-useful life machines? How do you handle seldom used or mothballed machinery? Leave your advice, questions, or comments with this post online.

- J.B. Titus, certified functional safety expert (CFSE), writes the Control Engineering Machine Safety Blog. Edited by Mark T. Hoske, content manager, Control Engineering,

ONLINE has related machine safety posts and other blog topics, including: Does a risk assessment need to be updated for a minor modification to a machine?

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