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!

[Mick Ohrberg]

The article states its the build-up of static rather than the phone itself sparking the fires.

Getting in and out of your car is much more likely to cause a spark, precisely due to static electricity. Especially in dry climate and cold days (when people are more likely to leave their engines running as well as get back in the varmth of their car during fueling). And yes, it has been shown that women are more likely to get back in their car during fueling.

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.

Re:Urban Myth!

[Dmala]

I don't think it's a doppler issue.

It's definitely not a doppler issue. Drivers on the Massachusetts Turnpike routinely use their cellphones at speeds in excess of 100mph, often while reading the paper or putting on makeup.

Well, our farts aren't exploding...

[SYFer]

They're flammable and they originate mere inches from our cell phones.

Re:Well, our farts aren't exploding...

[Anonymous Coward]

if your cellphone is only inches from your farts i would suggest you are holding it wrong

Re:Well, our farts aren't exploding...

[fmaxwell]

They're flammable and they originate mere inches from our cell phones.

There you go talking out of your ass again.

Re:Well, our farts aren't exploding...

[horza]

They're flammable and they originate mere inches from our cell phones.

You must be from Europe. I hear that in the USA the distance tends to be that little bit further.

Phillip.

It's not using the cellphone

[Oronwe]

The warnings about not using your cellphone at a gas station is because you might drop it and the battery pack might come loose. This could spark as well and cause a not-so-static discharge.

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

[horza]

No! Incorrect assumptions like that are exactly why these fires and explosions keep occurring worldwide. The battery could obviously cause a fire, all but the very smallest batteries can, but the primary hazard is sparks caused by the RF voltage induced in the pump nozzle. Under certain conditions of dimensions and position there are resonances at some of the cellular frequencies, which will magnify the actual voltage to the level where a spark will occur.

You are suggesting it's RF resonance causing the explosion as opposed to a spark from the phone igniting the vapours or any static discharge? Please point us to a single piece of evidence.

It amazes me how in the UK, where warning notices are to be seen quite often in filling stations, that imbeciles continue their pathetic and unnecessary conversations while filling. If I see one near me, I move, and quickly...... It is a criminal offence under the petroleum spirit regulations, it is time that it was enforced properly.

I personally don't believe there is a risk, I'm with the static theory.

BTW most HF/VHF/UHF communications equipment is potentially lethal in these circumstances. I know that cellular base stations are sometimes sited on the premises, they are carefully positioned, and the inverse square law ensures that the signal level at the pumps is well below the safety limit.

We all know about the inverse square law, and it's enough to take a mobile phone power down to a level not to affect the brain a few millimeters away let alone a whacking great conductor (with no pointy bits) a few feet away. I refer you to my answer to paragraph one.

It is sad that the general public are so ignorant and ill-informed as to constantly put other people's lifes at risk by this stupid behaviour. In the UK the law requires you to switch off before entering the filling station, off means off, not standby, because if the mobile needs to access the network or respond to an incoming call, its first and unpredictable transmission will be at full power!

That's not what I've read on the GSM protocol. I've read it latches on to the lower power signal to conserve battery.

Don't get me started on where else they are lethal such as on aircraft, at least one businessman is, very properly, in jail in the UK as a result of his wilful ignorance on that score. If I were the judge, I would have made it a life sentence, because he put so many lives at risk, even when told not to. If stiff sentences were handed out for using mobiles in filling stations, the practice would diminish substantially. It would not stop entirely, there is always some idiot who knows better than the safety legislators.

What an irrelevant arguement. This law is about potentially disrupting computer systems on a craft, not about making them explode. And in fact the maximum risk is when the craft is on the ground and not in the air.

Phillip.

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:It's not using the cellphone

[jridley]

It amazes me how in the UK, where warning notices are to be seen quite often in filling stations, that imbeciles continue their pathetic and unnecessary conversations while filling. If I see one near me, I move, and quickly...... It is a criminal offence under the petroleum spirit regulations, it is time that it was enforced properly.

Heck, I'd be happy if they just enforced the rule that states you must remain at the filling point while pumping. Every day I see people walking away, getting in their cars to wait for the pump, etc.

I, personally, twice in the last 6 years, have witnessed gasoline spilling out of a vehicle when the nozzle failed to kick off. One was a few spots over from me, I ran over and shut off the nozzle. About 2 gallons of gas on the ground.

Another time, I was **driving by** and saw gas spilling from a pickup with nobody around. I whipped into the station, came in close to the truck, slammed into park, jumped out, ran to the truck, and shut off the valve. The whole time, there was a woman inside the truck, talking on her cell phone. You should have seen the look on her face when I came roaring up, jumped out and ran at her truck. Of course, the look on her face when she realized she'd just pumped about 15 gallons of gas on the ground, under her truck, was pretty good too.

She just kept yapping "how did this happen?" I just said something like "the valves aren't perfect, sometimes they don't work. That's why you're REQUIRED BY LAW to stay by the valve when the gas is pumping. See, it says so right there on the pump." I just walked away; she was obviously not the kind of person who actually uses her brain or anything. She was still yammering when I went into the station to report the spill and wash the gas off my hands.

I was in Illinois once, and a station attendant actually got on the PA and said "Pump 4, you must stay within sight of the pump." When they didn't, she cut the flow to that pump.

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.

Cellphone Paranoia

[stoobthealien]

Moving on from the gas station thing, what are people's policies about cellphones (or mobiles as we call them in the UK!) and computers. I'm currently in my computer science lab and if I get my phone out of my pocket I'll be banned for the day.

Are they being overly paranoid? Can cellphones really disrupt your average PC in as much as they might ignite petrol fumes...

Re:Cellphone Paranoia

[timbloid]

> Can cellphones really disrupt your average PC in as much as they might ignite petrol fumes...

No, but they can put everybody else within earshot off their work, and into a slow state of boiling rage...

Listening to three other people's incessant mindless babbling over their mobiles for a few hours is a good way to get nothing done, and really angry about it...

I'm guessing their reasoning for banning your mobile is just common courtesy...

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.*

Pacemaker?

[Anonymous Coward]

all those signs at the gas pump telling you to to make sure your car, cell phone, PDA, pacemaker, etc.

Turn off you PACEMAKER? What?

Re:Mythbusters TV Show

[makomk]

Here in the UK, the program "Brainiac" tried to get petrol vapour to explode using a mobile phone. They put loads of open-topped containers of petrol in a caravan together with mobile phones and rang them. Nothing happened.

They did manage to get a very nice explosion by leading a wire to the cravan and getting soomeone wearing nylon clothes and standing on a bucket to touch the other end, though.

PS. They really liked blowing up caravans...

Also snopes link

[Nakanai_de]

Further coverage of this myth here.

The most disturbing thing about this article...

[Vellmont]

Is that the fire chief is so adamant about blaming cell phones rather than simple static electricity.

1. Cell phones emit minimum amount of power (no microwave heating of the fumes).
2. AFAIK there's no documented cases of cell phones starting a gasoline fire.
3. Electric sparks obviously can start gasoline fumes on fire. How do you think a spark plug works?
4. We all know how easily static electricity can build up from simply walking across a rug on a dry day.

Kinda makes you wonder just how much training the fire chiefs have. I'm sure they know how to fight fires, but at least this guy seems to have limited knowledge and analytical skills about how fires start.

Static electricity due to locking pump on

[cybergibbons]

It seems as if, reading the report, that nearly all of these accidents resulted from someone putting the nozzle into the vehicle, then locking it on, leaving, coming back, and a static discharge igniting the vapours near the filler cap.

This is reasonable - you quite often feel small static shocks. Especially in dry hot weather, perhaps explaining a high incidence of acccidents in Texas and Nebraska, and a lot less in humid coastal ares.

And when you are filling up, you often see clouds of vapour almost pouring out of the filler. These would be very easy to ignite.

Here in the UK you can't put a pump on automatic fill. You need to hold the trigger whilst all the time. The handle is grounded, so that as soon as you touch it, the static goes, and as long as you keep on holding it, there won't be a problem, as there will be no sparks.

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.

No it isn't

[Tau Zero]

You're not going to get high voltage out of a piezo transducer which is being driven from a 4.5 volt battery through a low-impedance path. And if you could get high voltage by dropping it, lots of people would have blown electronics from dropping their phones; you might notice that this does not happen.

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:i don't want to be a fireball

[danormsby]

Just do as advised... "make sure your car, cell phone, PDA, pacemaker, etc. are all turned off before you start pumping"

Make sure your pacemaker is switched off on your next visit.

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:i don't want to be a fireball

[rodney dill]

Too late, you are already flamebait

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.