Can Cell Phones Ignite Gasoline Vapors?

Iphtashu Fitz writes "Matthew Erhorn was filling his car with gasoline outside of New Paltz, NY when when he flipped open his cell phone to answer a call. The next thing he knew he was engulfed by a ball of fire. Luckily for Erhorn a quick thinking employee hit the emergency fire suppression system and he ended up with only minor burns. Firefighters investigating the accident concluded that the cell phone triggered the fire. Experts at The Petroluum Equipment Institute disagree however, attributing the fire to static electricity. Since 1992 the PEI has documented 158 cases of gas pump fires believed to have been started by static electricity. Apparently cell phone signals are too weak to ignite gasoline vapors, but the human body can generate enough static electiricy (60,000 volts) from simply sliding out of your car seat to do just that. Do you pay attention to all those signs at the gas pump telling you to to make sure your car, cell phone, PDA, pacemaker, etc. are all turned off before you start pumping?"

Comments

Urban Myth!

[musicscene]

The stats also show that women are "the cause" of more fires at the gas pump. Hey, don't blame me... it's just the stats, ma'am!

The Mythbusters took care of this MYTH in episode #2:

Episode 2: Cell Phone Destruction, Silicone Breasts, CD-ROM Shattering
In this episode, Jamie and Adam test several explosive theories. Can chatting on a cell phone while pumping gas cause the pump to blow up? Our mythbusters put themselves at risk so you don't have to. They also put silicone breast implants to the test at high altitude. Will they burst under pressure? Finally, we'll learn once and for all if high-speed CD-ROM players can really shatter a compact disc.

Re:Urban Myth!

[LocoMan]

The reason cell phones aren't allowed on airplanes also have to do with the way the cell phone networks work. They were designes to have a cell phone in range of mostly 3 or 4 cell phone transmitters (no idea what their real name in english is) at the same time, then they decide which one is the strongest and communicate you trough it. When you're airborne, the cell phone signal can be in range of hundreds of transmitters at the same time, clogging the whole service and making it reject lots of land-based calls. Which is probably why some airlines now allow you to use the cell phone, but only after landing. Or at least that's what the Iberia magazine said last time I went to Spain.

Re:Urban Myth!

[zulux]

PS - How do you get back in your car while refueling? Don't you need to squeeze the handle of the pump in the US?


In the US - There's usually a little peice of metal that you can flip to lock the handle in the squeezed position. So you squeeze the hande, flip the metal and can walk away and do other things.... like build up a static charge.

Short Answer: NO

[gizmonic]

They did a thing about this on Mythbusters on Discovery, and were unable to start a fire this way. They pretty much concluded that the static you build up from getting in or our of the car during a fill-up can cause a spark if you touch the car. And doing that near the fueling point can cause a fire. Of course, the worst thing you can do then, which most people do, is pull the hose out of the tank and proceed to spill a LOT of gas into an already burning fire. Not good, especially when you are the one removing the hose. Leave the handle and hose right where it is and get the hell out of there.

And here is a little more data on this urban myth.

NO!

[hummassa]

You are not telling the story in hope that people follow the link.
Here it goes, short version: they tried, they tried hard, to make a cell phone ignite gasoline vapours... and they failed miserably. They put the stuff in a closed environment, tested many concentrations of gas vapour, nothing worked.
The only way this happens is static electicity near the fuel entrance

Re:NO!

[GooberToo]

All you need is a good spark in the right air/fuel mixture. The fact that Mythbusters couldn't do it, doesn't mean it can't happen. Within the last 30-days, on the local news here in Dallas, I saw a static discharge start a car fire while at the pump. The person failed to ground themselves prior to starting to pump fuel. Once the vapors were in the air, they touched *something* (I don't recall where the spark occurred, sorry). Swoosh! Suddenly, the car was on fire. The guy experienced minor burns up his arm, which was holding the pump.

While I would personally guess that a cell phone starting a fire is doubtful, I think it would be foolish to rule out the risk completely. On a side note, some states have a law requiring all metal fuel containers to be filled ONLY while on the ground and you are required to keep the metal part of the nozzel in contact with the container at all times. It seems, static discharge bewteen a metal container and the pump's nozzle are not uncommon. In other words, those guys that are filling up that gas can from the bed of their truck, may be in for some trouble. Not to mention, an invitation for a ticket.

Morale of the story here? Make sure you properly ground your self BEFORE you start to pump gas.

Re:NO!

[egomaniac]

The fact that Mythbusters couldn't do it, doesn't mean it can't happen. Within the last 30-days, on the local news here in Dallas, I saw a static discharge start a car fire while at the pump. The person failed to ground themselves prior to starting to pump fuel. Once the vapors were in the air, they touched *something* (I don't recall where the spark occurred, sorry). Swoosh! Suddenly, the car was on fire. The guy experienced minor burns up his arm, which was holding the pump.

And that is exactly what was said on Mythbusters -- the danger is in static electricity. They showed a number of such fires being started.

The idea that a cell phone would start a fire borders on ludicrous, though. To start a fire, it would have to generate intense heat. The only reasonable way for a tiny electrical device with no heating elements to generate such heat is by creating a spark. But a spark represents a tremendous waste of energy -- why are you bothering to use your battery power to ionize the air, raise it to extreme temperatures, and generate the resultant light and sound? Cell phones didn't get to the kind of battery life they have now by wasting their energy producing sparks.

Either A) something was seriously wrong with the guy's phone, or B) the fire started via a spark of static electricity, which is a well-documented occurrence.

UK Experiment Says No

[Sirch]

A rather trashy science program in the UK on Sky, called Braniac: Science Abuse performed an experiment where they covered a trailer in gasoline and left a mobile phone in it. They then phoned it. Nothing happened. Then they added more gas and mobile phones, and phoned them all at the same time. Still nothing happened.

Not sure it proved anything, so they blew it up with something anyway. Bit of detail here.

It can't be that likely...

[gadders]

In the UK they cell phone transmitters on petrol stations.*

Also snopes link

[Nakanai_de]

Further coverage of this myth here.

sounds possible

[scampiandchips]

With process plants if we got any level of escaped gas etc.. you initate a level 1 shutdown which kills power to everything.
Even the UPS sytem that fed an automated tranmitter, the idea being that the transmitted radio waves could induce current and possibly lead to a spark in any nearby metal.
Petrol isn't quite as flammable, but the same principle applies. If you had you phone near a suitable surface an incoming call may well have the same effect.
Personally i'm more concerned about the mobile phone masts they have installed in petrol station signs.

Re:Well..

[LightningTH]

The real issue is that people get in and out of the car and dont grab ahold of the car, or some other object to ground themselves before grabbing the nozzle. This is when the static electricity gets released and becoems dangerous.

This is also why women are the leading cause to the fires, as they get in and out to do something. None of the fires, according to MythBusters, are started by older people, as older people will grab the car to get out, or stand there the whole time holding the handle to the pump causing them to stay grounded.

Let's distinguish

[The Tyro]

between fire and explosion with Gasoline... that might help delineate what we're talking about here.

For a cell-phone held in the hand, we're probably most worried about igniting gasoline vapors, leading to a subsequent fire (unless you're bathing your cell phone in liquid gasoline while talking on it. Nobody's doing that, are they? Please tell me no...)

Gasoline has a flash point about 40-50 degrees below zero, so unless you're in the arctic circle somewhere, gasoline will almost always be producing some vapors. Those vapors can be ignitable and explosive... but only within a certain range of concentration. The range is between the LEL (Lower Explosive Limit) and the UEL (Upper Explosive Limit)... This naturally varies by compound... but for standard gasoline is roughly 1.5% and 7.5%, respectively.

I've never studied it personally, but I'd think the odds of getting just the right concentration around your cell phone (multiple feet from the nozzle) such that it leads to an explosion and fire are extremely small.

Static electricity? Now that's a much more likely culprit... there have been multiple cases where that's happened.

Re:Well..

[Chanc_Gorkon]

You NEVER get back in a car when fueling. This lady suffered because of it. You are safe when fueling as long as you never open/close the car doors and more so if you don;t get in and out. It's tha static that causes this. Same thing goes when filling a can of gas for your lawn mower. Putting it in your car when filling not only puts you at risk for the gas overflowing, but also for the static to buiild up.

Cell Phones, PDAS and everything else do not even come close to causing a gas station fire...unless your using a non manufacturer batter with explosion problems! :) According to Nokia anyway.

Re:It's not using the cellphone

[tiger99]

Curiously, sparks from metal tend to be of very low energy, even if seemingly quite bright. In the days before Sir Humphrey Davey invented the miners safety lamp, coal miners were causing frequent methane explosions by using candles, many disasters were so caused. The safest thing they had at the time was the Spedding Steel Mill, which was a spinning steel disc rubbing on a flint, they worked by the light of the continuous stream of sparks, but methane would not ignite (usually!). It was proved to be unsafe in the end, but did not cause nearly as many explosions as might have been expected.

Much later on, in the 1960s IIRC, a manager at Ford in the UK had some petrol (gasoline to all you US /.ers) poured into pools in the concrete-surfaced yard, then a tractor dragged assorted pieces of scrap iron through it for several hours, no ignition! It was concluded that most car fires following accidents are as a result of sparks from damaged wiring, not friction. However, some believe that repeating the Ford experiment with modern unleaded fuel might give entirely different results, as apparently it does ignite more easily, so is more at risk from friction sparks, or RF sparks from mobiles.

I have actually seen someone smoking while filling a lawn mower from a can. I wonder how many times he got away with it before disaster struck. Never seen it at a filling station though.

Re:It's not using the cellphone

[cr@ckwhore]

I can't believe the parent is a +5 ... perhaps the moderators just saw a long post and figured it must be worth +5, without even reading the content first.

First of all, there would be little (if any) voltage induced on the pump handle. BUT .. .there wouldn't be any current... voltage by itself is pretty worthless without current to make something happen. BUT... if you happened to induce a small voltage on the pump handle (1 milliwatt - I'm being generous) with your little cell phone, wheres the current going to flow? That's right, nowhere ... there's no complete circuit. In fact, you're likely to get more RF energy out of your car when the engine is running than when you're on your cell phone.

"Under certain conditions of dimensions and position there are resonances at some of the cellular frequencies..."

No.

... which will magnify the actual voltage to the level where a spark will occur.

No. Resonance does not "magnify" voltage. Here's a quick definition of resonance for you... "Condition in a circuit when, for an applied alternating voltage of a given frequency, the inductive and capacitive reactances are equal."

Ok, so you might be thinking, "well, antennas resonate and that's how we receive radio waves". Well bucko, an antenna resonates because it's part of a circuit containing inductors and capictors which make it resonate at the desired frequency. The current created through the inductors still needs to be amplified many times before it's strong enough to drive a speaker! AND, even then, it's probably still not enough current to create a spark!

A gas pump handle has few qualities of inductance. Obviously, it's not going to resonate without some type of inductor... and last time I checked, there's nothing remotely close to an inductor in a gas pump handle.

Discovery channel has already done a great job of killing this myth. Fires at the pump are caused by static discharge. Period. When a driver gets out of the car, they create a shit load (pun) of static potential when their ass slides across the car seat. This is less likely to happen with old people because they almost always need to grab the car to assist their exit, thus grounding the static charge.

But, for us "young" people, it's common to get out of the car without ever grounding. Happens to me all the time ... 9/10 times when I go to shut the door, I expect to get a static shock. Happens so often that I'm now very careful at the pump. Discharge on your car, before you accidentally/unknowingly discharge into the pump.

Static discharge will create an open spark!! What more do you need for ignition?? Fuel, spark, oxygen. Fire. Resonance? Sorry bucko, doesn't work.

Re:is the voltage on the antenna really enormous?

[Ungrounded Lightning]

is the voltage on the antenna really enormous?

Absolutely.

An antenna is a transmission line terminated with an open circuit. (This IS a striaght-line - or bent in various ways - transformer.) The voltage at the end is quite high. If it's excited at its resonance, it is limited only by the losses from radiation, resistance, and surrounding materials.

Consider the "firefly" decorations once popular on CB antennas. 4.5 watts into 52 ohms produces 15 1/4 volts. A neon lamp requires about 90 volts to ionize and I think it's about 45 to sustain. Yet put one on the end of the antenna and it lights up merrily when you key the transmitter. No big illegal power amplifier required.

Repeat after me: 3 volts do not arc.

Sure it does, under a number of conditions.

You're thinking of STARTING an arc in air. For three volts the gap would have to be microscopic.

But when breaking a circuit with current flowing through it you end up with exactly that microscopic gap initially. Once the air is ionized the arc can be sustained by a very low voltage. And with any inductance in the circuit at all (even the stray inductance from the wiring) the voltage will climb to maintain the arc until the current through the inductor is finally brought to a halt by the reverse voltage. So the arc can be "pulled out" to significant lengths.

This is EXACTLY the mechanism that produces the voltage spike in the primary (and thus also in the secondary) of the transformer in a contact-point type auto ignition.