there are lots of books on laboratory procedures with chapters on cleaning glassware.
I’m sure there are.
No real cite, mostly due to laziness. I used to pump out the acid baths for labs at UC Davis, though, so I can say, anecdotally, that some biofilms can leave residues that will interfere with the results of the next experiment if they aren’t given a special acid bath. And straight sulfuric or nitric acid isn’t enough to do it.
This lab safety manualfrom Oklahoma State University discusses a need to shift from Chromerge ™ to Nochromix ™ because the hexavalent chromium has to be disposed of as a hazardous waste, now, rather than being run down the drain. UCD had to make a similar shift in the late eighties.
If you go to chromerge sales sites, you’ll see that it lists removing metal contamination as a reason for using it. Folks who got chatty while I was pumping their acid talked about organic residue. Between the two, I’d guess that there are both metals and organics that don’t come off of glass by boiling or soaking in bleach water.
This is not to say that there will necessarily be anything dangerous on glassware that hasn’t been supertreated, just that there is stuff that will still be there after ordinary sterilization procedures, and it will come off slowly later, in quantities that can mess up experimental results. I can see an insurance company deciding that this is an unacceptable risk.
BTW, do not try setting up an acid bath at home.
Thank you - I am quite surprised by this.
I re-read this and decided that it might need clarification. There is stuff that will stay on glass through ordinary sterilization procedures. There is no way to tell if that sort of stuff was in the flood water. It’s possible that boiling or bleach water would work well enough. But there would be no way to tell withough expensive testing.
Also, if a biofilm leaves organic residue, that’s not the same as leaving microorganisms. So it might be perfectly possible to sterilize the glassware. Insurance companies aren’t big on uncertainties, though. I’m guessing that’s pretty much what this comes down to.
I’m pretty sure the routine use of acid baths for lab glassware suggests that it’s unlikely for general flood water to make glass brittle. It could be that they’ve found that people will argue about contamination (an idea they’re used to) but not to induced brittleness (a completely new idea). It could also be that they’ve run into odd situations where glass became more brittle or that they’ve had legal claims that glass had become more brittle. Any time that there might be legal claims, the dollars will trump the actual physics.
This I’m 100% willing to accept. But, again, there’s a huge difference between, say, testing solutions for heavy metals (I had a girlfriend who worked for a spell in a chemistry testing lab, so I know at least a little about this) and washing some mud residue that MIGHT have some sewage diluted in it. (Further downstream? I would have no doubt there would be some–but that only comes from all-too-intimate knowledge of that particular waterway and the adjacent sewers/road drains.)
I mean, fer cryin’ out loud, our local harbor has massive chronic contamination from a long-gone chrome plant. If everything were as dangerous as every neurotic makes it out to be, we would have evacuated like Chernobyl ages ago.
I don’t know that ‘brittle’ is the word I would have used to describe it, but yes, for re-usable beer bottles, the sterilization procedure was one of the things that made bottles more likely to break. It etched the surface of the glass. We didn’t use acid though: we used an alkali
And they did break. Safety glasses and safety boots were compulsory around the bottle lines.
Good point.
If you think this through, there is no profit motive for the insurance company, assuming they’re paying for the replacements. Even if they aren’t, I doubt this is a significant factor.