Selenium Rectifiers an old fashioned way to convert AC power to DC power that are still out there and more dangerous as they grow older

Before modern Zener and other diodes came on the market and where used in a Bridge Rectifier

https://www.youtube.com/watch?v=PfWmIQfYIRI

 

 Configuration to convert AC to Dc Power there was the Selenium Rectifier

https://en.wikipedia.org/wiki/Selenium_rectifier

A metal device with fins coated with Selinium which was used in all kind of applications from simple radios and toy train layouts  to large industrial machines 

 They where used in products up till the late 60s as they where very dependable and could handle higher voltages better than previous copper oxide rectifiers developed in early 30's 

Unfortunately with age these rectifiers break down and can give off extremely toxic gases  due to Nickel and Selenium plating and there are still plenty of them I come across in old fire alarms and industrial machines and old tube radios people love to collect .

I try to change them out with modern units where I can to keep an old machine running safely but its not always easy to match everything up. 

Plus radio purest when restoring radios want to keep everything original. 

So should I be worried if I have them in my bussiness or home.

Yes there is concern so know it can happen and have a plan in place should one brake down and give off fumes immediately leave the room and ventilate the room  if possible and call 911  

this is a hazardous materials situation.

They may be neat to look at and are part of history but do so from a distance .