Cell phones - an ignition source?

Today, at a meeting of like minded people, we had an interesting discussion on how the use of a cell phone may be dangerous in a classified area.One of the participants opined that is is static electricity when using a cell phone that develops the spark that could prove to be an ignition source. Whatever the methodology, it is prudent not to use cell phones in a classified area. An incident in a platform in the Gulf of Mexico in 2002 is quoted below:
"A contract panel specialist was working on an open platform master control panel that used supply gas for the instrumentation. The contractor stated he was carrying a cellular phone that was turned on and rang while he was working on the panel. The employee claimed that when he flipped the bottom piece of the cellular phone to answer the call, a flash fire occurred causing second degree burns on his forearms and “sunburn” on his nose and cheeks. At the time National Safety Alert No. 5 was issued, it was believed that the cellular phone may have ignited the flammable gases or vapors in the area of the open platform master control panel when the phone had been flipped open to receive the incoming call.As part of the investigation of this fire, they sent the hand held cellular phone involved in the flash fire to an independent third party testing laboratory.
Although the cellular phones’ battery provided sufficient energy to ignite the test gases during the testing it did not. As a result, it was the opinion of the independent third party testing laboratory that it is unlikely that the cellular phone would have ignited a flammable mixture of methane or propane under actual field conditions and that the cause of the flash fire was something other than the cell phone.
Based on this information and investigation, we were unable to conclusively identify the ignition source of the fire. However, we have not ruled out the possibility that the fire could have been ignited by static electricity, a spark from the metal master control panel door coming into contact with a metal handrail, or a wrench striking metal inside the control panel".
Read more of the article in this link
Read a brochure by Shell in this link