May 1999 Volume 21 Number 2

Health and Safety

The sky is falling! the sky is falling!

The Associated Press wire service ran an article recently about the crash of an Air Force jet. It seems the Velcro that normally secures a glasses case for the pilot's night vision goggles failed. The case fell down and its strap got caught on a switch that disconnects hydraulic power. When the pilot pushed the case out of the way, the switch got switched. The $10.2 million dollar plane nose dived and crashed. (The pilot, Capt. Ronald Halley, thankfully, ejected safely.)

This seems like an appropriate cautionary tale for conservators. It is the weakest thread in your personal protective safety net that can cause your person to crash and burn. What is your Achilles heel, or Capt. Halley's Velcro?

Not to sound too Chicken Little-ish, but there is no reason, to my mind, for any conservator to use any of the following substances: benzene, carbon tetrachloride, carbon disulfide, and chloroform. (If you have any of these in your studio, I would recommend disposing of them at the earliest opportunity. Consider availing yourself of the next hazardous waste roundup in your community.)

I was watching a cute cartoon the other day. It was an X Files spoof, featuring Chicken Little as agent Fox Mulder and a fox as agent Dana Scully.

One of my favorite television shows is The X Files. A good episode weaves around and you are never quite sure where the story line is headed. Sometimes there is a disturbing surprise at the end.

Unnamed sources have informed me that hexane (also called n-hexane) should not be used. Heptane (n-heptane) appears to be much safer and have virtually identical solvent properties. Methanol, DMF, DMSO, the cellosolves, Aroclor, thiourea, methylene chloride, and carcinogenic dyes should only be used with full protective measures in place. Always wear appropriate gloves, protective clothing, respirator when appropriate, and work with adequate ventilation (fume hood, spray booth or out of doors).

I wouldn't repeat this outside of this column, but it is my feeling that anyone in the same working space should be informed when nastier chemicals are being used.

While the government would not confirm it-or condone it-my own feeling is that in many conservation situations, the use of personal protective equipment (PPE) is a matter of personal choice. Normal exposures should be engineered to be below dangerous levels. But anyone potentially exposed must be well enough informed to decide what level of exposure he or she is comfortable with. That personal choice must be made through informed consent. And, the appropriate PPE must be on hand for them to take whatever protective measures they feel are appropriate. Obviously it is wrong (and often against the law) to allow colleagues or workers to expose themselves to a hazardous situation regardless of notions of informed consent and free will.

Meanwhile, the cartoon agents were working on a case with three little pigs whose homes were being destroyed by a mysterious force . [I apologize for digressing into pop culture again. While it is true that my daughter is too young to watch TV, I have been ever vigilant in watching as many cartoons as I can so that when that day comes, I can offer appropriate criticism (in the art historical sense, of course) and background.]

Vigilance. . . I'm in love with disposable nitrile gloves. They are more expensive than latex, but are allergen free, more durable, and resistant to an unbelievable range of solvents. They are often tough enough to be reused. I don't think latex or vinyl examination gloves have any place in the conservation studio any longer. If you don't already have a box of these babies, splurge and get some. [A few people I know don't like the smell of these nitrile gloves. If you find them a bit pungent, take a handful out of the box and let them off-gas elsewhere before using them.]

The truth is out there . . . If you use UV light examination, you should have UV absorbing glasses or goggles on hand. It is a wise precaution to use the protective glasses when using long wave UV but it is an absolute must if using short wave radiation.

Anyway, Chicken Little/agent Mulder was sure the houses were being felled by falling sky while in fact it was the big bad wolf. The big joke at the end, when no one else was looking, a chunk of sky did fall.

I want to believe that you would never "point" your brushes in your mouth, either when new or subsequently. A good trick for pointing your brush that I use is to put a small amount of saliva on the back of your (clean) hand--the fleshy area between your thumb and fingers. The brush can be pulled though the "spit" and then shaped with your fingertips.

Always use clean sterilized cotton or swabs for tasks such a spit cleaning. This is very important and often overlooked in studios. If your cotton sits out in the open, it is exposed to solvent vapors, bits of who knows what, and hundreds of years worth of dirt and unspeakable yuck. You are going to roll that cotton onto a swab and moisten it in your mouth? Keep your "spit cleaning" cotton, swabs, and swab sticks separate. Only use new swab sticks or swab sticks that have never been used for anything other than "spit cleaning." I mark the ends of my "spit safe" swab sticks with a yellow highlighting marker and never use the sticks to roll any swabs other than those for "spit cleaning." When the yellow is too grimy and dingy to see, it is probably time to retire the swab stick. If there are a number of people sharing the same work space, you might also want to add additional markings to denote ownership of these swab sticks. [This isn't strictly a health and safety issue, but more like not wanting to share someone else's toothbrush.]

The government will confirm this trick for dampening a swab stick to help cotton grab while rolling. Do not put it in your mouth. Either use the same method described above for pointing your brush or dunk the stick into water before rolling.

If you, as I do, reuse swab sticks (particularly bamboo based skewers) for solvent based cleanings, you might have noticed that solvents will readily move through the stick and into contact with your hand. A nice way around this problem is to infuse almost the entire length of the swab stick with a low viscosity epoxy, leaving the tip untreated to grab the cotton. Again, mark the handle of these treated swabs (before infusion) with a marker.

Question everything! Use a closed or nearly closed receptacle for your used swabs. Good choices are empty soda cans (covered with paper and marked "X" so that no one mistakes them for a consumable beverage), metal lidded glass jars with a triangular hole cut into the lid, or a plastic lidded coffee can with a slit in the lid. Any of these can assist you in pulling the cotton off of a hand-rolled swab. Never remove your swab tips with your fingers, Agent Scully would certainly tell you that a pair of tweezers is much more sensible. And if you do remove your swab tips with tweezers, don't deposit them in an open tray when working with solvents. And what becomes of your smelly swabs? Make sure they are disposed of in a way that won't contaminate your indoor air.

Assume nothing. Anything that might be inherently hazardous should be treated as such until rigorous scientific analysis has proven otherwise. Insoluble, old, white fill material?--assume it is lead until testing shows it is not. Old animal specimen?--assume it has been treated with some form of poison until it has been demonstrated to be free of mercury, arsenic, or other historically applied insecticides.

An unidentified source told me a story that made my skin grow clammy. I was explaining that a treatment was taking an inordinately long time because the lead white removal required so much in the way of safety precautions. My client got quiet for a moment and said that it was very good that I was so careful. A friend of his died recently from mercury poisoning. It took the doctors a long time to diagnose the malady. The source of the contamination, the friend's hobby--restoring vintage radios.