Can ear-plugs be reused?

Ear plug dispenser in a factory

During noise assessments I have seen some factories try and limit the number of disposable ear plugs people use in a day but there are multiple issues with this.

As well as the issue around hygiene, soft foam ear plugs generally do not take very well to being reused and it can have an impact on safety by the plugs getting less effective with multiple used.

Impact of reusing ear plugs on their effectiveness

Unless they are designed to be reused, soft ear plugs do lose their effectiveness with repeated use.

I use the EARsoft FX foam plugs a lot, not so much for work but for sleeping in hotels where there is no punishment strong enough for the mouth breathers who always talk loudly on the corridors assuming everyone else is also awake.

The EARsoft FX are among the strongest hearing protection on the market with an SNR of 39dB, but I noticed that with repeated use the fit was getting looser, so being a noise-nerd and qualified to do hearing tests and with my own audiometer, I did some tests.

I put some brand new ear plugs in and then did a hearing test while wearing them. I then wore the same ones a couple more times and then on the third time I put them in I did another hearing test while wearing them. Same audiometer, same booth.

Audiogram of reused ear plugs

The red line in this audiogram is the result while wearing a brand new pair of ear plugs.

The black line is the same pair of ear plugs but on the third time I had inserted them.

On the chart, lower means more noise was blocked.

As you can see, the worn ones have noticeable worse performance across the entire frequency range than the brand new pair, varying from about 10dB worse at the higher frequencies (the right hand side of the graph) to about 15 to even 25dB worse at the lower frequencies (the left side of the graph).

You can physically feel the difference when wearing them. The new ones feel firmer when rolled up and feel like a better fit in the ear, while the worn ones feel much softer when rolling and also feel looser in the ear and this is confirmed in the data.

It is worth highlighting that it is not how long the ear plugs were worn, but the number of times they were squished down and allowed to expand. With repeated rolling and squishing they lose their ability to expand quite so well. That would therefore apply to someone taking plugs out two or three times in a day for breaks, etc.

Reusing ear plugs which are not designed for it really does make their performance worse. This is important as hearing protection should be chosen for the specific noise risk, so if a noise assessment has identified a need for hearing protection which reduces noise by say 25dB then it needs to be 25dB, and the reduction from reuse could mean people are not getting enough protection and remain at risk.

Single-use ear plugs are indeed single-use only.

Reusable ear plugs

If an employer wants people to reuse ear plugs there are a lot on the market which can be reused, meaning they are washable and have a storage case to keep them clean. They are usually more the flanged silicone design than soft foam.