I’m not sure when Hill Brothers Chemical Company first started manufacturing Magnesite, however, it’s safe to say it’s been around California, Arizona, Nevada and other Western states for a long long time…it’s distinctive bull nose edges are a sure sign of what the deck has on it.
What I do know is that up until 1977, Magnesite was manufactured using Asbestos as an ingredient. Hill Brothers sold millions of square feet of the material as interior and exterior flooring. This 1999 article from the LA Times discusses the allure of Magnesite, although it doesn’t discuss Magnesite’s little problem of asbestos in it… https://www.latimes.com/archives/la-xpm-1999-jul-11-re-54828-story.html
Fast forward to 2002 and Hill Brothers was found liable for 20,000,000.00 after losing a suit brought by a women who had Mesothelioma from asbestos in the floors of the home she grew up in. https://www.kazanlaw.com/verdicts/20000000-verdict-for-woman-exposed-to-asbestos-in-her-own-family-home/
RIP Magnesite. Today Magnesite is not sold by Hill Brothers anymore. From what they told me, a key ingredient was difficult and costly to source due to demands for it from other industries. As a result, they halted manufacture of Magnesite and are no longer supporting the product.
However, the product is still found everywhere in homes, mult-families and older condo’s. This leaves a huge number of people at risk to exposure to Asbestos due to unknowing owners and contractors just treating it like any product and ripping it out, releasing friable asbestos into the environment.
DeckExpert.com recommends to any owner of a property with Magnesite on it to have asbestos testing done on the product no matter when it was installed. It’s better to be safe than sorry and it is a risk reduction for the owner against future claims.
Only Cal-OSHA approved Consultants can test, only Cal-OSHA asbestos certified contractors can remove it. In speaking with several people, they all said that remediation and sealing areas up to prevent release of friable asbestos when demolition is taking place is paramount. Special respiratory breathing apparatus is required, your dust mask from Home Depot will not help you. DO NOT ATTEMPT TO REMOVE MAGNESITE YOURSELF!
Bottom line, owners of multi-family buildings with Magnesite on them should not attempt to have the product restored or repaired. The service life of Magnesite is up and it’s time to replace it. Magnesite is dead, long live Magnesite!