Safety officials have received 83 reports of <A HREF="http://news.yahoo.com/news?tmpl=story&u=/ap/20041123/ap_on_hi_te/exploding_phones">cell phones exploding or catching fire</A> in the past two years, usually because of bad batteries or chargers. U.S. phone makers and carriers say most fires and explosions are caused by counterfeit batteries and note that in a country with some 170 million cell phone users, the number of accidents is extremely low.