Nice storage spot, construction guys!

So, it looks like storing large amounts of flammable plastic under a bridge is perhaps not a great idea. Anyone having to deal with this?

When I was a kid, they built a big apartment complex in a field behind my house. (A sprawling collection of 3- and 4-unit bungalows.) The workers threw some kind of tarry paper - peel-off from self-stick asphalt shingles? - into the finished but empty middle swimming pool until it was full.

As this was the days of prevalent smoking, I guess it’s no surprise that it caught fire. I still remember standing no more than about 100 feet away, looking at what looked like a vertical propane torch as the concrete bowl focused the hot-burning paper goods. I can’t remember if the pool was ruined or not.

This part sounds crazy:

To be fair, would you have ever thought that keeping spools of plastic conduit under a concrete and steel bridge would cause that to happen?
Has that ever happened?
This is what we’re talking about. Either it was a fluke that they caught on fire, and I’m surprised that they’d take down an overpass, or it was arson, and that’s different, but I’m still surprised that it would do that much damage.

Faulting them for that, ISTM, is like telling people they shouldn’t park their cars in their garage because the tires could catch on fire.

Sometimes when I’m trying to get a pile of wood scraps to start burning, I use some piece of old plastic to get it started. Plastic burns scary hot–it is essentially frozen gasoline. (I once spent a long time to get a large, rotten oak that had finally fallen over burning. After a long time trying to get it burning with less extreme methods, I finally scrounged up a large igloo cooler that I could live without. It did the trick. And a bridge acts as a roof to hold the heat from a much larger amount of plastic. So it doesn’t surprise me at all that it would destroy a bridge.

1996 – An arson in March at an illegal tire yard underneath a section of I-95 in Philadelphia caused $6 million in damage and completely closed a section of the highway for weeks and partial closures for six months.[6][7]

the above is what i thought of when i saw the fire on the news. they are looking at a long repair.

And I’ll bet prior to that, your igloo cooler wasn’t kept outside, in the middle of your backyard, so that it didn’t burn down your house or garage.

As for plastic being ‘essentially frozen gasoline’. Well, sure, but so is the asphalt roadbed and half the stuff in your house. You don’t keep a cell phone in your pocket, do you?

I’m still going to say that, unless you can show me that this happens on some kind of regular basis, there’s no way anyone could have expected that keeping spools of plastic conduit under a bridge could caused this.

I’m guessing it was arson. I’d be surprised cigarette accidentally flicked onto one of the spools could even get it going.

We also had a truck fire near here where the guy thought it was a good idea to stop under a (secondary road) overpass. They say there’s no damage but as the bridge and road surface are a decade overdue for refurb, I drive over it with a little trepidation.

Yes Joey these kinds of things happen on a regular basis:

I just had a brilliant idea: Why don’t we set up a Department of Homeland Security at the Federal level and similar departments at the state level who would systematically check for vulnerabilities to terrorist attack of our infrastructure such as this? [All terrorists would have to do is start a little fire.]

there are rules and regulations about what, where, and how things can be stored in businesses and public buildings and “public service” suggestions for homes. Seems like there would be similar rules for roads. (If there weren’t before, there will be now.)

I’m well aware and so far all of my dealings (which are at least once a year) with the local health, building, fire and electrical inspectors (don’t see an OSHA person, but I do have to deal with occasional ‘insurance inspections’) have never even so much as hinted at not keeping plastic indoors, much less outdoors under structures with concrete covers.

I’m guessing there isn’t now and won’t be after. Maybe I’ll be wrong, but since I’m still guessing this is arson, you can’t say ‘don’t put plastic conduit here because someone might set it on fire and ruin the bridge’.

It’s going to depend on the MSDS for this particular conduit. Also, there’s a question of if it had recently been cleaned with a solvent or if there was any conduit cement stored there as well.

An easy way to see plastic burn (unless they have changed the formula):

Take the carrier from a six pack of beverages. Cut the hole in such a way that the result is more or less a straight strip.
GO OUTSIDE AND MAKE SURE NOTHING FLAMMABLE IS UNDER YOU

Use a match or lighter - it will ignite quite easily.

You will get flaming globs dropping from the carrier - and thick, acrid, black smoke.

A great trick for small children.

Small children do not burn that way.

Burning plastic also makes an almost musical “whooshing” sound as it drips.

Small children not so much.

Without knowing about the Atlanta collapse, this could have been about the I-35W bridge collapse in Minneapolis in 2007. A contributing cause (besides poor gusset design) was construction workers placing 597,000 pounds of materials (mostly sand - I saw the piles there the day before) right above the point that collapsed. I wondered then if that was a good idea…

Did everyone notice that it was the Georgia Department of Transportation than was storing these construction materials under the bridge that caught fire?

No, but I did see this:
“the flammability of HDPE is relatively low. If HDPE materials burn, they would have to be exposed to a high temperature flame for a considerable amount of time”
-Tony [<-apparently a brother or relavetive, somehow, of someone I know, small world], President of Plastics Pipe Institute.

He’s also quoted in that article as saying
“Somebody had to start a fire. It doesn’t combust by itself, it needs fuel,”
“Someone had to do it, It’s not like someone would have dropped a match and it started.”

Of course, that’s just an a quote for a CNN piece, it doesn’t really amount to anything, other than to tell us the stuff isn’t going to catch on fire because it was out in the sun or muffler fell off a truck and some sparks hit the pipes as it skidded past it.

I’m curious how they already have three names, three arrests and one person still in custody so quickly. Did they turn themselves in? If not, I have to assume the area has cameras and at least one, if not all, are regulars at the police department and the cops knew where to find them.

3 arrests made.

3 charged in ‘maliciously set’ Atlanta highway fire may have been smoking crack