KaBoom

This post is not really about the kids or the family in general, but it’s the kind of story you share with everyone so I’m posting it here instead of on my research blog.

I caught a lucky break today. Really lucky. A glass bottle of nitric acid exploded in the lab. The pictures show us part way into the cleanup and aren’t good enough quality for you to really appreciate what happened.

We normally don’t have nitric acid in the lab and it can be nasty stuff. In short, it’s an extremely strong oxidizer and in the concentration I acquired it at is rated “severe” for both contact and inhalation. Strangely enough, despite the fact that it is an acid, it does not attack stainless steel and so I had used it last night to dissolve a significant amount of lead out of my stainless steel vacuum chamber.

If you want to really scare yourself, two of the first items that come up in a Google search of “nitric acid inhalation” are scholarly articles on the rare occurrence of people surviving just such an incident. So I was particularly careful last night handling a 70% solution by using a fume hood, apron, goggles, etc. . For cleaning the cell I diluted the solution to ~40% and made a small container of ~10% solution for lighter use. I stored the used nitric acid from the cell in a 4 liter glass bottle.

Today while I was making final preparations for putting my chamber back together I needed to clean off the small valve that had been on the lead contaminated chamber as well. I used a cotton tipped swab with my 10% solution to lightly wipe away the face of the piece and then I ran a very small amount of the solution through the valve to clean the inside. This small amount of nitric acid got mixed with a small amount of acetone and a small amount of isopropyl alcohol also used on the valve and the I disposed of this into the bottle of used nitric acid I had created last night. I then placed the bottle next to 2 four liter bottles of acetone (1 full, 1 not) and 1 full four liter bottle of isopropyl alcohol which were all waiting to be picked up and disposed of by Chemical Management. Then, fortunately, I walked outside the lab to talk with my advisor.

We have never used nitric acid and aren’t very familiar with it. Even though I did a fair amount of research on it before using it I was still unintentionally ignorant in my use. Not being a chemist, I regrettably was not thinking of the isopropanol as an organic which should never come into contact with a strong oxidizer like nitric acid. The problem was that when a small amount of the alcohol was mixed with a small amount of the 10% solution at room temperature nothing happened, and so I thought nothing of disposing of it in the much higher concentration of used nitric acid. However, after a short amount of time and some warming, pressure from the reaction built quickly inside the bottle. The principle to remember here is that a very small amount of liquid/solid is all that is required to create a huge amount of gas.

As I sat outside the lab with my advisor there was a sudden, muffled “kaboom” inside the lab and, as I was looking at the lab at the moment, I saw the top of a glass bottle hit the door accompanied by the sound of millions of pieces of glass hitting something. Despite the fact, that these bottles have a plastic cap, the plastic is apparently not the weakest part of the bottle. The pressure was enough to completely pulverized the bottle the acid was in and glass dust and small pieces coated everything near the bottle and were found as far across the lab as it had a clear path. The blast was enough to decimate the other three 4 liter glass bottles sitting next to it as well as take the paint off the wall, dent the side of the fridge, and put a large crack across the acrylic plate that was covering the sink nearby.

What went right about this? First, there was no one in the lab at the time which was quite miraculous. The bottle was completely surrounded on all sides when it blew which not only muffled the blow but very effectively limited the spread of the acid. Of the considerable spread of liquid around the site almost all of was isopropanol and acetone with the nitric acid almost completely draining to the floor behind the cabinet it was sitting on. Also, the acid was sitting on a metal cabinet rather than something organic like wood. The large amount of acetone present immediately mixed with the acid effectively diluting it and preventing the the acid from mixing with the isopropanol in the same way that created the blast. No hot elements or exposed electrical connections were near enough the blast to ignite flammable vapors from the chemicals. The arrangement of cabinets and racks in the lab at the moment effectively created a blast wall protecting all the optics tables and our desk area. The explosion occurred almost directly under the air exhaust for the lab allowing for quick evacuation of fumes and gasses. And finally, Chem Stores was still open so that we were able to acquire the materials needed to cleanup a disaster of this magnitude (the spill kit in the lab is intended for small disasters).

In the end, I’m amazed how limited the damage was. The most hilarious part of the incident happened when we called Chem Management. A few months ago we had a chilled water line burst in the lab and flood it. When that happened Chem Management rushed over like it was a 4 alarm fire. They shut down the lab and would not let anybody in to attempt a cleanup or salvage anything until they could find out what was in the chilled water line. First of all, this was ridiculous given that the chilled water is pumped into every single lab without warning or concern that someone might come into contact with it or misuse it in some way yet they did not know what it contained or if it was dangerous and they didn’t even have a material safety data sheet for whatever it contains. As it turned out, there is a mild anti-oxidant in the water to protect the lines and it’s completely safe. However, when we called to report an explosion with gallons of chemicals spread over the lab they could have cared less. It seems like they’re more interested in making a good show in a non-issue than taking care of a serious problem that might generate a report on their end. You’d think concern for safety and property damage would win out since if that had been the case they’d have a really hard time explaining why they didn’t bother to respond.

Anyways, I now count this as the 3rd time I should have been killed/seriously maimed in my life and I wasn’t. There is no reason I shouldn’t have been standing at that sink like I was 5 minutes earlier. I went to talk with my advisor on a whim. I should be full of glass and acid right now and probably permanently blind. The other times include walking over a high voltage power line in the sleeting rain, and not being present in the lab when an undergraduate unwittingly made a pipe bomb using hydrochloric acid years ago (both good stories for another time). It makes me think I am somehow being protected as part of some larger purpose, which frankly scares me slightly more than the thought of being seriously injured. At any rate, I’m grateful to be writing this tonight and not laying in a hospital bed. It amazes me the mercy God extends to someone who deserves it so little.