Subject: By what mechanism does hydrofluoric acid cause death?

Recent episode of ER (based I think on Nov incident in New York 
involving a sanitation worker killed when a drum of HF ruptured and he 
inhaled the vapor as well as being exposed to liquid.  In episode they 
mentioned that HF combined with calcium in blood? (bones) resulting in 
heart failure.  Missed the explanation on the show (if one was given).  
Would appreciate it if could help.  

Thanks 

Re: By what mechanism does hydrofluoric acid cause death?