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It really doesn't take much. It really doesn't. You don't even need a grinder. Oily rags can ignite spontaneously. People usually laugh at the phrase "spontane

It really doesn't take much. It really doesn't. You don't even need a grinder. Oily rags can ignite spontaneously. People usually laugh at the phrase "spontaneous combustion" because it's so often associated with "spontaneous human combustion." But actual "spontaneous combustion" does happen in certain (not uncommon) circumstances. See: https://www.nfpa.org/-/media/Files/Public-Education/Resources/Safety-tip-sheets/OilyRagsSafetyTips.ashx https://www.nfpa.org/-/media/Files/Public-Education/Resource... And what makes things even scarier, is realizing that buildings, ships, etc. that are either under construction or undergoing maintenance are more "at risk" because alarm systems, automatic fire suppression systems (eg, sprinklers), etc. are often times not in place yet, or disabled, while work is going on. This is one reason it's so common to see a building complex that is under construction burn to the dirt if it catches fire, as opposed to a finished building where you might get a "room and contents" fire. No sheetrock, just miles and miles of exposed wood, no sprinklers, no alarm - recipe for disaster.

nostrademons 6y ago
> Oily rags can ignite spontaneously. That happened to a friend of mine. He was doing some woodworking and threw a linseed-oil soaked rag in the trash, then went to work. He returned home to his apartment on fire and a bunch of firetrucks blocking the driveway. Linseed oil apparently spontaneously combusts at 120 degrees and generates heat as it dries, so it can cause a fire in normal 70-80 degree weather.
- RotANobot 6y ago
  Woah. I feel like I might have heard about Linseed oil’s propensity to spontaneously combust but forgotten about it. Thanks for the reminder.
- michaelcampbell 6y ago
  Woodworkers are warned all the time about this. Lots of fires caused by hobbyists finishing furniture that aren't aware of it.
IgorPartola 6y ago
Oily rags are super dangerous. Depends on the type of oil or thinner but definitely something to keep in a small sealed metal container.
- black6 6y ago
  Linseed oil is the usual culprit. It oxidizes more readily than other oils at room temperature, and a pile of rags can insulate enough for the center to reach autoignition temperatures. The low smoke point for linseed oil also makes it well-suited for seasoning cast-iron cookware (only be sure, please, not to use boiled linseed oil, as it contains lead.)
  - Arainach 6y ago
    >low smoke point for linseed oil I would naively think you would want an oil with a high smoke point for seasoning. Can you elaborate on why a low smoke point is preferable?
    - black6 6y ago
      You want it to smoke when seasoning. That's an indication that free-radicals are being created which set off the polymerization of the oil and create the seasoning. Low smoke-point oils are more convenient because they start polymerizing at lower temps.
      - black6 6y ago
        You don't want it to smoke when cooking, because ingesting the free-radicals is generally considered unhealthy ;)
        TheSpiceIsLife 6y ago
        This is a glaring connection I rarely see people make. In fact, I've been banging on about it for 15 or so years, and, I kid you not, you're the first person I've seen being this up. Strange! Unusual cross section of knowledge: I studied nutritional medicine in a formal capacity for four years 2000 through 2003 inclusive, and I'm also a welder by trade.
jefftk 6y ago
> buildings, ships, etc. that are either under construction or undergoing maintenance are more "at risk" because alarm systems, automatic fire suppression systems (eg, sprinklers), etc. are often times not in place yet, or disabled, while work is going on Reminds me of the loss of the Normandie / Lafayette: "At 14:30 on 9 February 1942, sparks from a welding torch used by Clement Derrick ignited a stack of life vests filled with flammable kapok that had been stored in the first-class lounge. The flammable varnished woodwork had not yet been removed, and the fire spread rapidly. The ship had a very efficient fire protection system, but it had been disconnected during the conversion and its internal pumping system was deactivated." https://en.wikipedia.org/wiki/SS_Normandie#Fire_and_Capsizing https://en.wikipedia.org/wiki/SS_Normandie#Fire_and_Capsizin...
- ZanyProgrammer 6y ago
  Or the very recent fire on the USS Bonhomme Richard.
- mindcrime 6y ago
  This kind of thing is surprisingly common. The recent fire on the USS Bonhomme Richard had a similar issue. Since the ship was in maintenance, on-board fire-suppression systems had been disabled, delaying the onset of firefighting efforts, according to Admiral Sobeck https://en.wikipedia.org/wiki/USS_Bonhomme_Richard_(LHD-6)#July_2020_fire https://en.wikipedia.org/wiki/USS_Bonhomme_Richard_(LHD-6)#J... Another one that didn't get as much national attention was the fire on the SSG Edward A. Carter, Jr at the Sunny Point Military Ocean Terminal back in 2001. According to a subsequent Coast Guard report, the ship’s second assistant engineer started a transfer of about 20 tons of heavy fuel oil from the port and starboard overflow tanks to a central settling tank. The transfer was left unsupervised other than by automatic equipment. “Their electronic system measured the tank levels and sounded an alarm if the preset levels were exceeded,” Sledge said. “If you are starting to overfill the tanks, it sounds a warning tone.” Unfortunately, because cables to several tanks had become contaminated with fuel oil, false alarms had become a repeated nuisance. The easiest solution was to simply turn off the alarms. https://web.archive.org/web/20120723160038/http://www.fireworld.com/ifw_articles/silent_alarm-0908.php https://web.archive.org/web/20120723160038/http://www.firewo...
organsnyder 6y ago
A local hardware store burned down a while ago because of an oily rag. They had a spill in the paint department, and the employee who cleaned it up wasn't aware of the precautions needed.
- ghaff 6y ago
  You don't hear about this danger as much as you used to--probably because a lot more paints are water-based than used to be the case.
  - throwaway0a5e 6y ago
    You hear about stuff like that way more than you used to because every time you go on the internet you have to skim over the low effort comments pointing out the rare failure modes in which everything is dangerous to find the real content. The world doesn't need a lecture on proper jack stand usage every time vehicles are mentioned and doesn't need a lecture on linseed oil fires every time deck finished are mentioned but it gets it anyway.
    - jacquesm 6y ago
      I for one am pretty happy about the linseed oil stories in this thread because the low ignition temperature is something that I wasn't aware of.
      - imcoconut 6y ago
        same
      - formerly_proven 6y ago
        How? There's a warning on literally every product containing linseed oil even in the EU.
        ghaff 6y ago
        Products have warnings about approximately 100 gazillion things that can happen that basically no one reads.
djmips 6y ago
And it makes me think of fires caused by accidental optical focusing of the sun such as a polished metal dog bowl as one odd example and others such as hanging glass artwork.
- blackflame7000 6y ago
  I accidentally burned my dinning room table after leaving a magnifying work lamp on the table the night before that caught the sunlight through a window in just the right way to focus it onto the wood.
- mattacular 6y ago
  Or catching a translucent bottle of hand sanitizer sitting out in the console of your car
- mikeyouse 6y ago
  We had our windows washed last year and came home to a fresh burn mark on the floor in the hallway from where apparently the sun had been in the exact right spot with clean enough windows to focus a beam of light... We were fortunate that it didn't focus on something more flammable than a hardwood floor.
- chasd00 6y ago
  a buddy of mine is an architect. he wants to design a building with a concave facade such that when the sun is just right it produces basically a death ray. "imagine you're sitting in your office, causally glance out the window, and see a bird explode for seemingly no reason... " heh
  - longwave 6y ago
    The Walkie Talkie building in London has already achieved this: https://en.m.wikipedia.org/wiki/20_Fenchurch_Street#Solar_glare_problem https://en.m.wikipedia.org/wiki/20_Fenchurch_Street#Solar_gl...
  - samatman 6y ago
    So, Cathedral of Christ the Light in Oakland, basically.
agumonkey 6y ago
Talking about that, lots of lithium pouch thrown in bins. Be warned. ps: some videos to show how stupid a rag setup goes into fire https://www.youtube.com/results?search_query=self%20combustion%20rag https://www.youtube.com/results?search_query=self%20combusti...
praptak 6y ago
Speaking of spontaneous combustion - ammonium nitrate will spontaneously ignite in the presence of some impurities. Ammonium nitrate plus zinc powder is a mixture that only needs a drop of water or just sufficiently humid air to ignite.
- mindcrime 6y ago
  Another one is just plain ole organic matter, like mulch. Back in my days as a firefighter, our district included the county landfill. After one of the hurricanes that came through, they had gone around collecting all the downed trees, and chipped them up into mulch, and located this HUGE pile of mulch at the landfill, where county residents could come and get free mulch / wood chips for their gardens or whatever. Sounds great, right? Except it turns out that a huge mountain of decaying organic matter, left exposed to the southeast NC sun in July and August will periodically catch fire spontaneously. We went out there a few times to put that mess out. Not an easy task. You have to bring in heavy machinery to dig into the piles in order to get to the seat of the fire...and of course the landfill was nowhere near a hydrant, so we had to call out half the tankers in the county to set up a tanker shuttle... uuugggh.
  - jacquesm 6y ago
    The sun is actually not much of a factor in there. What makes this happen is that the mulch rots which is an exothermic process and it insulates very good as well. So the core temperature of pile will slowly creep up until you reach the ignition point. The same will happen to bales of hay that are taken from the field too wet.
    - chasd00 6y ago
      bales of rotting wet hay is where barn fires come from.
      - jacquesm 6y ago
        Yep. They also sometimes spontaneously combust in the field.
tyingq 6y ago
I had a water heater almost start a fire recently. Installer didn't shield some plastic insulated cable at a point where it exited through a metal hole. Small nick in the insulation plus a little time. It made several 4 inch diameter black spots before the breaker blew.
martin_ 6y ago
I was once treating my window ledge with Linseed Oil and was quite surprised when the cloth set on fire from direct sunlight ignited!

nostrademons 6y ago

> Oily rags can ignite spontaneously. That happened to a friend of mine. He was doing some woodworking and threw a linseed-oil soaked rag in the trash, then went to work. He returned home to his apartment on fire and a bunch of firetrucks blocking the driveway. Linseed oil apparently spontaneously combusts at 120 degrees and generates heat as it dries, so it can cause a fire in normal 70-80 degree weather.

RotANobot 6y ago
Woah. I feel like I might have heard about Linseed oil’s propensity to spontaneously combust but forgotten about it. Thanks for the reminder.
michaelcampbell 6y ago
Woodworkers are warned all the time about this. Lots of fires caused by hobbyists finishing furniture that aren't aware of it.

IgorPartola 6y ago

Oily rags are super dangerous. Depends on the type of oil or thinner but definitely something to keep in a small sealed metal container.

black6 6y ago
Linseed oil is the usual culprit. It oxidizes more readily than other oils at room temperature, and a pile of rags can insulate enough for the center to reach autoignition temperatures. The low smoke point for linseed oil also makes it well-suited for seasoning cast-iron cookware (only be sure, please, not to use boiled linseed oil, as it contains lead.)
- Arainach 6y ago
  >low smoke point for linseed oil I would naively think you would want an oil with a high smoke point for seasoning. Can you elaborate on why a low smoke point is preferable?
  - black6 6y ago
    You want it to smoke when seasoning. That's an indication that free-radicals are being created which set off the polymerization of the oil and create the seasoning. Low smoke-point oils are more convenient because they start polymerizing at lower temps.
    - black6 6y ago
      You don't want it to smoke when cooking, because ingesting the free-radicals is generally considered unhealthy ;)
      - TheSpiceIsLife 6y ago
        This is a glaring connection I rarely see people make. In fact, I've been banging on about it for 15 or so years, and, I kid you not, you're the first person I've seen being this up. Strange! Unusual cross section of knowledge: I studied nutritional medicine in a formal capacity for four years 2000 through 2003 inclusive, and I'm also a welder by trade.

jefftk 6y ago

> buildings, ships, etc. that are either under construction or undergoing maintenance are more "at risk" because alarm systems, automatic fire suppression systems (eg, sprinklers), etc. are often times not in place yet, or disabled, while work is going on Reminds me of the loss of the Normandie / Lafayette: "At 14:30 on 9 February 1942, sparks from a welding torch used by Clement Derrick ignited a stack of life vests filled with flammable kapok that had been stored in the first-class lounge. The flammable varnished woodwork had not yet been removed, and the fire spread rapidly. The ship had a very efficient fire protection system, but it had been disconnected during the conversion and its internal pumping system was deactivated." https://en.wikipedia.org/wiki/SS_Normandie#Fire_and_Capsizing https://en.wikipedia.org/wiki/SS_Normandie#Fire_and_Capsizin...

ZanyProgrammer 6y ago
Or the very recent fire on the USS Bonhomme Richard.
mindcrime 6y ago
This kind of thing is surprisingly common. The recent fire on the USS Bonhomme Richard had a similar issue. Since the ship was in maintenance, on-board fire-suppression systems had been disabled, delaying the onset of firefighting efforts, according to Admiral Sobeck https://en.wikipedia.org/wiki/USS_Bonhomme_Richard_(LHD-6)#July_2020_fire https://en.wikipedia.org/wiki/USS_Bonhomme_Richard_(LHD-6)#J... Another one that didn't get as much national attention was the fire on the SSG Edward A. Carter, Jr at the Sunny Point Military Ocean Terminal back in 2001. According to a subsequent Coast Guard report, the ship’s second assistant engineer started a transfer of about 20 tons of heavy fuel oil from the port and starboard overflow tanks to a central settling tank. The transfer was left unsupervised other than by automatic equipment. “Their electronic system measured the tank levels and sounded an alarm if the preset levels were exceeded,” Sledge said. “If you are starting to overfill the tanks, it sounds a warning tone.” Unfortunately, because cables to several tanks had become contaminated with fuel oil, false alarms had become a repeated nuisance. The easiest solution was to simply turn off the alarms. https://web.archive.org/web/20120723160038/http://www.fireworld.com/ifw_articles/silent_alarm-0908.php https://web.archive.org/web/20120723160038/http://www.firewo...

organsnyder 6y ago

A local hardware store burned down a while ago because of an oily rag. They had a spill in the paint department, and the employee who cleaned it up wasn't aware of the precautions needed.

ghaff 6y ago
You don't hear about this danger as much as you used to--probably because a lot more paints are water-based than used to be the case.
- throwaway0a5e 6y ago
  You hear about stuff like that way more than you used to because every time you go on the internet you have to skim over the low effort comments pointing out the rare failure modes in which everything is dangerous to find the real content. The world doesn't need a lecture on proper jack stand usage every time vehicles are mentioned and doesn't need a lecture on linseed oil fires every time deck finished are mentioned but it gets it anyway.
  - jacquesm 6y ago
    I for one am pretty happy about the linseed oil stories in this thread because the low ignition temperature is something that I wasn't aware of.
    - imcoconut 6y ago
      same
    - formerly_proven 6y ago
      How? There's a warning on literally every product containing linseed oil even in the EU.
      - ghaff 6y ago
        Products have warnings about approximately 100 gazillion things that can happen that basically no one reads.

djmips 6y ago

And it makes me think of fires caused by accidental optical focusing of the sun such as a polished metal dog bowl as one odd example and others such as hanging glass artwork.

blackflame7000 6y ago
I accidentally burned my dinning room table after leaving a magnifying work lamp on the table the night before that caught the sunlight through a window in just the right way to focus it onto the wood.
mattacular 6y ago
Or catching a translucent bottle of hand sanitizer sitting out in the console of your car
mikeyouse 6y ago
We had our windows washed last year and came home to a fresh burn mark on the floor in the hallway from where apparently the sun had been in the exact right spot with clean enough windows to focus a beam of light... We were fortunate that it didn't focus on something more flammable than a hardwood floor.
chasd00 6y ago
a buddy of mine is an architect. he wants to design a building with a concave facade such that when the sun is just right it produces basically a death ray. "imagine you're sitting in your office, causally glance out the window, and see a bird explode for seemingly no reason... " heh
- longwave 6y ago
  The Walkie Talkie building in London has already achieved this: https://en.m.wikipedia.org/wiki/20_Fenchurch_Street#Solar_glare_problem https://en.m.wikipedia.org/wiki/20_Fenchurch_Street#Solar_gl...
- samatman 6y ago
  So, Cathedral of Christ the Light in Oakland, basically.

agumonkey 6y ago

Talking about that, lots of lithium pouch thrown in bins. Be warned. ps: some videos to show how stupid a rag setup goes into fire https://www.youtube.com/results?search_query=self%20combustion%20rag https://www.youtube.com/results?search_query=self%20combusti...

praptak 6y ago

Speaking of spontaneous combustion - ammonium nitrate will spontaneously ignite in the presence of some impurities. Ammonium nitrate plus zinc powder is a mixture that only needs a drop of water or just sufficiently humid air to ignite.

mindcrime 6y ago
Another one is just plain ole organic matter, like mulch. Back in my days as a firefighter, our district included the county landfill. After one of the hurricanes that came through, they had gone around collecting all the downed trees, and chipped them up into mulch, and located this HUGE pile of mulch at the landfill, where county residents could come and get free mulch / wood chips for their gardens or whatever. Sounds great, right? Except it turns out that a huge mountain of decaying organic matter, left exposed to the southeast NC sun in July and August will periodically catch fire spontaneously. We went out there a few times to put that mess out. Not an easy task. You have to bring in heavy machinery to dig into the piles in order to get to the seat of the fire...and of course the landfill was nowhere near a hydrant, so we had to call out half the tankers in the county to set up a tanker shuttle... uuugggh.
- jacquesm 6y ago
  The sun is actually not much of a factor in there. What makes this happen is that the mulch rots which is an exothermic process and it insulates very good as well. So the core temperature of pile will slowly creep up until you reach the ignition point. The same will happen to bales of hay that are taken from the field too wet.
  - chasd00 6y ago
    bales of rotting wet hay is where barn fires come from.
    - jacquesm 6y ago
      Yep. They also sometimes spontaneously combust in the field.

tyingq 6y ago

I had a water heater almost start a fire recently. Installer didn't shield some plastic insulated cable at a point where it exited through a metal hole. Small nick in the insulation plus a little time. It made several 4 inch diameter black spots before the breaker blew.

martin_ 6y ago

I was once treating my window ledge with Linseed Oil and was quite surprised when the cloth set on fire from direct sunlight ignited!