Hazards from wooden railings of the stair cases

In the past one month, I had two minor incidents of penetration of small wooden piece of about one millimeter in length and much lesser thick into my fingers. 

This happened as I am taking support of railing during the use of stairs. 

Photos of railing and wooden speck are attached below.

It is found that the wooden railings are not smooth finish as they appear. The protrusions of the railing are posing hazard to users. 

Stainless steel railings that are anti-corrosive are better than these wooden railing. 

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