|Posted on Wednesday, July 09, 2003 - 08:02 am: ||
Laboratory safety is very important for ALL chemical procedures, but don't throw out the baby with the bath water. Safety precautions and an MSDS for RTX solution are posted here.
In general, the precautions are:
SAFETY CAUTIONS: Some Latent Print Examiners have told me that they will not work with chemicals like Rhodamine 6G (a dye stain commonly used to tag/enhance superglue developed prints) because its MSDS states that it is an experimental (possible) carcinogen. Yet, these same examiners seem unaware that common household black pepper they keep on the kitchen table everyday contains experimental carcinogens. Of course, the amount of black pepper one would have to consume to be at risk of danger is ridiculously huge... so we all continue to eat black pepper. Oh, and the mutagens and carcinogens present in bread, apples, and many other common foods (see a list here) would probably mean you are going to completely change your eating habits if you are going to have zero tolerance for carcinogens and mutagens (versus following safe exposure/consumption guidelines).
1. RTX processing should be done in a fume hood, with adequate ventilation or in a fume chamber. As with ninhydrin and other chemical procedures, a face shield or safety goggles with side shields should be worn along with chemical resistant plastic or rubber gloves and a lab coat.
2. Wear plastic or rubber gloves when using the solution, or your hands may turn black. If your hands should become discolored, please apply Sodium hypochlorite (NaOCl) 3% aqueous solution to remove the black stains and then wash thoroughly with water or remove the stains with alcohol. (Hint - Chlorox brand bleach is 5.25% sodium hypochlorite and you can dilute it with water to bring it down to 3%. For example, mix one liter of Chlorox brand bleach into 3/4ths a liter of water to produce a 3% aqueous sodium hypochlorite solution.)
3. The DEVELOPER should absolutely not be sprayed or blown out directly toward the human face.
Is pure ruthenium tetroxide toxic? Absolutely! But we are talking about a solution already mixed so you are not handling the pure stuff. So what does toxic mean when you are talking about those milligrams per kilogram LD50 (lethal dose 50% of the time) numbers used in MSDS sheets? The RTX solution (not pure ruthenium tetroxide) MSDS states, "The LD50 in mg/Kg rating for RTX-halogenide solution is 5570, (oral, mouse)." Hmmm... is that better or worse than table salt, sugar, or beer? Let's take a look at what that means:
So that means that per the MSDS, it is safer than beer or table salt, but not as safe as sugar. (Click here to see the online reference used for the above toxicity levels.)
|Material||LD50 (mg/kg)|| subject/route |
|sucrose (cane sugar)||29700|| rat/oral |
|RTX solution|| 5570|| rat/oral |
|sodium bicarbonate (baking soda)||4220||rat/oral |
|sodium chloride (table salt)||3000||rat/oral |
|ethanol (grain alcohol)||2080||rat/oral |
|sodium cyanide||6.4||rat/oral |
|sarin (nerve agent)||24||human/percutaneous (skin contact) |
|VX (nerve agent)||0.14||human/percutaneous (skin contact)|
In 1973, I attended training in Moorestown, NJ (at an unnamed "fingerprint laboratory") where my classmates and I sprayed benzidene from plastic bottles onto blood-stained floor tiles inches from our faces. At the time, none of us knew what the danger considerations were for benzidene. Nowadays, many crime labs will not let benzidene in the door because it is such a powerful carcinogen. Theoretically any time after 1993 I could have started developing liver cancer from that benzidene exposure... we all try to the do the best we can with what we know at the time.
The greatest risk in your day is the drive to work (and to crime scenes, lunch, etc.), but you're probably not going to stay put because the roads carry risk of permanent injury or death.
Bottom line - observe ALL laboratory and field processing safety guidelines... but, don't discount procedures at the first inkling of safety concerns. I have posted a government safety report about latent print processing techniques online here.
|Posted on Tuesday, July 08, 2003 - 10:29 pm: ||
We researched the possible use of RTX in our lab, and the more I learned about ruthenium tetroxide, the less I want to do with it! What is most disturbing is the fact that it's producer leads you to believe that ruthenium tetroxide is safe because it disolved in a non-flammable solvent. Flammability is only one issue. It is a well known fact that ruthenium tetroxide is TOXIC. RTX should be handled with great care and with adequate ventilation.
|Posted on Monday, June 26, 2000 - 07:57 am: ||
The RTX data at onin.com is from Kenzo Mashiko and Takashi Miyamoto of Japan. I updated the info with new data from them... including info that RTX allegedly does not interfere with subsequent processes, and also an MSDS.
|Posted on Monday, June 26, 2000 - 07:53 am: ||
I was just wandering around your web site (its pretty cool) and saw that you have information on RTX. It states that it is not dangerous. Could you post an MSDS on this product?
|Posted on Friday, May 19, 2000 - 01:26 pm: ||
Just recently received a sample of RTX developer solution to test. My initial testing on raw wood was excellent. Would appreciate feedback from other(s) with experience using this product to possibly answer some application questions regarding compatibility with Amido Black?