Thursday, February 12, 2009

Awesome lab injuries

Julius, the lab eccentric, wandered into my room recently when the other two occupants were gone. As he moseyed out again, he casually mentioned to me, "I just planted a bomb in your room."

"A stink bomb?" I asked, confused.

"No! That would be rude! It's dry ice in an eppendorf tube; I'm hoping it'll explode near Stefan."

An eppendorf tube is a small plastic tube with a lid, and of course dry ice is frozen carbon dioxide that sublimates directly to vapor instead of melting to liquid. It expands when it sublimates, and if it's in an enclosed space the pressure builds until something gives.

About five minutes later I'd forgotten Julius' warning and Jongmin was back at his desk when there was a startling loud bang in the room.

"Oh, Julius said he planted a bomb," said I.

"Ah!" said Jongmin at once. "Dry ice. Eppendorf tube."

"You've heard of it?" I asked.

"In my old lab," said Jongmin, "we would do RNA extractions, and because it was hard to digest the cell wall we would freeze the cells with liquid nitrogen and--" he made motions of grinding with a mortar and pestle-- "by hand, and then we would scoop it into an eppendorf tube. But we couldn't let it thaw or the RNA would be no good. We had to do it quickly. So sometimes some trace of liquid nitrogen would remain in the sample, and we would add lysis solution and shut the tube, and a few minutes later, BANG!"

"Were there dangerous chemicals in the lysis solution?" I asked.


Phenol's one of the few honestly nasty chemicals we use in the lab. It eats away human flesh. You don't really want a tube of phenol exploding!

Later, Julius and I were working in Joel and Smadar's room. "Was Stefan around when the bomb went off?" he asked.

"No," said I.

"Oh, dry ice in an eppendorf tube?" asked Joel.

"Am I the only person who's never heard of this before?" asked I.

"Probably," said Joel.

So I've learned a new trick. The best part is the time delay; by the time the bomb goes off you're long gone and people have forgotten who was there.

I have had plenty of experience with exploding tubes, if not deliberately planted ones. I used to work in the cytogenetics lab of a cancer hospital where we would be given the leftover blood samples of patients. Cancer cells often have weird chromosome configurations, which our lab studied, so blood samples from sufferers of rare cancers were valuable material to us. Every evening I'd centrifuge the latest blood samples and pipet off the white blood cell layer to freeze in cryotubes which I'd then store in freezer canes submerged in liquid nitrogen. (Exactly the same way they store human embryos, actually-- so wrong.) Then when we were ready to study those samples, I'd fetch the tubes from the LN2 and thaw them out. But sometimes the frozen culture medium had expanded in the freezer, causing the tube's lid to crack open a tiny bit and allowing liquid nitrogen to seep in. Then when the tube warmed up, the opening in the tube would reseal but the LN2 would try to expand, and the tube would go off like a bomb. If I recall correctly, after one explosion we couldn't find where the tube with its frozen blood sample had gone! You're supposed to treat all blood samples as highly biohazardous, as if they all were infected with HIV, so you really don't want them flying around the lab to parts unknown.

We learned not to overfill the cryotubes, and to crack them open as soon as they were out of the LN2-- that stopped the explosions. But I hadn't learned this yet on September 11, 2001. No kidding, that was the date. Being on the west coast, most of us had heard the news before heading to work, so we were keyed up that morning, upset and nervous. I'd been asked to pull a bunch of blood samples and I had an ice bucket of cryovials sitting on a lab bench, fresh out of LN2. Suddenly there was a BANG, and Mari shrieked and clapped a hand over her ear, where a flying shard of plastic had hit her! I'm so glad it didn't draw blood. On that day, that might have done us in.

Speaking of liquid nitrogen, I was warned in safety meetings never to work with the stuff in a closed room. Always make sure the door is open, they told me. Have plenty of ventilation. It seems that somebody who failed to observe this rule ended up dead. A freezer can leak liquid nitrogen without anyone noticing, since the liquid immediately flashes to vapor when you let it out. Nitrogen gas is colorless and odorless and composes 80% of the air we breathe. So it's generally as harmless as can be, but when huge quantities of it are leaking from a freezer, the nitrogen vapor pushes all the oxygen out of the room. It's a bit like carbon monoxide poisoning-- the man died of asphyxiation without even realizing he was in danger. To him it would have felt like he was breathing just fine... till he passed out.

Liquid nitrogen is dangerous in another way. It's stored in big tanks with built-in vents that hiss when the pressure builds up enough for vapor to escape. Sometimes the hissing is loud and annoying. So some dude at a university in Texas decided that blocking the vent would be a good idea. He had a few blissful hiss-free days. Then the pressure got so high that the tank exploded, and just like a little eppendorf tube would, the tank took off like a rocket. It shot right through the ceiling of the lab, then through the ceiling of the lab above that, and would have broken through the roof of the whole building if it hadn't hit a concrete support beam. Fortunately no idiots were killed in the making of that disaster. Larry, our safety rep here at Caltech, made sure to show us interesting pictures of the damage.

I've mentioned phenol, also called carbolic acid. It's very useful to extract proteins from DNA. It was also useful to the Nazis to execute people by intravenous injection-- St. Maximillian Kolbe was killed that way in Auschwitz after he'd been in a starvation cell for three weeks (having volunteered to take the place of another prisoner). So you want to avoid getting injected with phenol. On the other hand, if it spills on you, disaster may be averted if you wash off your skin right away, and strip off any clothes that were splashed with it.

But of course a person would be inhibited about taking his clothes off in the workplace. So Larry told us the cautionary tale of the man who spilled phenol on a leg of his jeans. He rolled up the leg, rinsed off his skin, rolled the jeans leg back down again and went on with his work. Of course there was still phenol in the fabric. And the thing about phenol is that it has an anesthetic effect as well as a flesh-eating effect, so the man didn't feel the damage being done. He ended up hospitalized with a severe open wound. Ick... I'm glad no one's spilled phenol where I've worked.

Okay, my very favorite exotic lab injury story happened to my labmate Meredith. She had run some DNA out on a gel and stained it with ethidium bromide to visualize the DNA with UV light. UV light is damaging, and you especially don't want to look at it directly, so there are plastic face shields and other devices. But it was late, and Meredith was in a hurry to cut out the DNA band she needed, and the safety shields are cumbersome. So she slapped the gel on top of the light box, switched on the UV, located the band she wanted and stooped low over the box with no face shielding to cut the band out of the gel with a razor blade.

Everything went fine. She finished processing her DNA and went home. Then she noticed that she was going blind.

By the middle of the night she couldn't see a thing. Her roommate took her to the emergency room, and the doctor was mystified. He asked many questions to try to pinpoint the cause of the sudden blindness, finally asking, "What do you do for a living?" When she said she was a graduate student in a biology lab, he asked what she had done that day and the UV light was unmasked as the culprit. "It's like a sunburn on your retina," the doctor explained.

Meredith had to fly up that weekend to San Francisco to meet her fiance. There was an odd scene in the airport-- he was waiting for her just outside the gate, but he wasn't allowed to go to her, so he called to her while she walked blindly toward the sound of his voice. Thanks be to God, the injury wasn't permanent and she had her sight back in about three days. I'm guessing they were a very nervewracking three days, though!

As for me, I've sometimes had a sore right wrist from repetitive motion... and that's it. No worse injuries than that. I like it that way. :)

In my first real lab job I used to fantasize that the lab was being attacked by some sort of terrorists, and the cytogenetics department banded together to build dangerous weapons from chemicals and materials on hand, and defeated the bad guys. I think that would make a great movie.


Joe of St. Thérèse said...

Sweet movie plot, LOL!

Diliberately messing with chemicals is fun :)

Rachel Ann said...

This is fascinating...who knew science could be fun?

Gary Keith Chesterton said...

Julianne Moore could play you in the movie.

"In a world where scientists and lab workers spend their days at the bench...until one day..."

LAB RATS. Rated R. Starts Friday.

JimAroo said...

This makes me wish I had some ability in biology or chemistry, Then maybe I could get a job blowing things up and splashing flesh eating chemicals on cockroaches. I never had this much fun at any job I ever had. I am so jealous.

Rachel Gray said...

Well, it's all fun and games until someone gets hit with exploding phenol. :) Jim, it's funny you should mention the cockroaches because our lab's in the basement of a very old building, and we do see the little buggers around!

GKC, I love it! Lab Rats! And this celebrity face recognition site did match my photo to Julianne Moore's.

JimAroo said...

hmmmmm face recognition matched me with Ben Stiller and Dustin Hoffman.... how should I take this?

Rachel Gray said...

Rain Man!