Is there any code or standard for Fire alarm log book?
Cancer does not spread like some diseases do, cancer is usually a disease from the person's genes. Although, some bacteria like Chlamydia pneumoniae is associated with lung cancer and Streptococcus bovis which is associated with colorectal cancer, they are pathogens not live cancerous cells. You said that you got some cancerous cells inside your body, your immune system will not recognize those cells and your immune system will destroy them. It is very unlikely that cancer will spread to you. If the patient had HIV, then you could be at risk if you took some of the blood into your own blood, if it was just a couple of cells you may not be in such a risk. Cancer isn't contagious either. The only way that you could get cancer is for your cells to mutate into cancerous cells, cells that your body doesn't recognize wouldn't have an effect because they would probably get destroyed. If the cells contain the pathogen that caused the cancer you could be in danger, if the cells don't contain cancer than your cool.
Take it down. Take it to an electrical supply store. They can tell you the manufacturer, and if necessary, what to replace it with. Why would you need to know the brand name, unless you are replacing it?
