Subject: What are possible effects of massive levels of ionization?

For a science fiction idea... In an enclosed space, such as an underground 
cavern, suppose there is an object which is ionizing the air at a massively 
exponential rate. Essentially, I need to know what precautions (if any) 
scientists/technicians monitoring such a site would need to take. I kind of 
ignorantly imagine mini-lightning discharges or massive build-ups of static or 
something. Are there any biological hazzards associated with massive levels of 
ionization?

Re: What are possible effects of massive levels of ionization?