FIRST AID FOR CHEMICAL EXPOSURE
A. FIRST AID PRINCIPLES
1. If necessary call an ambulance ‑ state type of accident, its location and the number of persons injured. If the injured person can walk, you can probably get to MUMC Emergency faster by walking.
2. KEEP CALM and keep onlookers away. Give the victim fresh air. DO NOTHING ELSE unless ?????
3. Stop the bleeding.
a. If bleeding is copious, it must be stopped by applying a large compress to the wound with direct pressure on the wound.
b. If bleeding is not profuse, remove all foreign matter from the wound, wash carefully with soap and water then apply antiseptic to the wound and to an additional inch surrounding it.
c. Bandage all wounds securely but not tightly.
4. Prevent physical shock by placing victim in reclining position with the head lower than the body (except in cases of head injuries). Control any bleeding and keep victim warm with blankets. Keep victim's airway open. If he vomits, turn head to one side. Do not give alcoholic liquids. KEEP CALM yourself and reassure the victim.
5. Restore breathing by artificial respiration if you have been trained in this technique.
6. Remove the victim from the hazardous environment if chemicals have been spilled or there are dangerous fumes, vapours or gases in the air. Wear a Scott Air Pack if required.
7. Never give liquids to an unconscious person or to persons with abdominal or lower chest injuries.
8. Do not move a person with possible broken bones or possible head or internal injuries unless fumes or fire necessitate it.
9. In case of puncture wounds (e.g., from broken glass, tubing, thermometers, etc.), send the victim to hospital directly since it is difficult to remove all foreign material and to reach the bottom of such a wound with antiseptic.
10. For swallowed poisons, give 2 to 4 glasses of water immediately. Call an ambulance or the Poison Control Information Centre 1-800-268-9017 for advice.
B. CHEMICAL INJURIES TO SKIN
The extent of injuries caused by Chemicals is directly related to the concentration and quantity of the caustic agent, the type and duration of skin contact, the extent of skin penetration and the chemical's intrinsic mechanism of action. It is absolutely essential that you are aware of the potential dangers of the reagents you are using before beginning reactions and that you are prepared to deal with splashes on the skin and clothes.
The most obvious precautions in avoiding skin contact are the use of gloves and face shields; heavy rubber gloves and rubber aprons may be required in special cases. The thin, disposable gloves available in stores are good for aqueous solutions and are attractive to use because they don't affect your feel of experimental apparatus. Unfortunately, these gloves are readily attacked by some organic solvents and reagents, especially acetone, methylene chloride, chloroform, etc.; they provide minimal protection from these chemicals and their solutions. Rubber gloves are also available in the stores which are substantially more robust than the disposable gloves and are much more resistant to organic solvents; however, even these gloves soften if immersed for a period of time in a solvent such as methylene chloride. In the back of the Cole-Parmer catalog is a list of many chemicals and the type of plastics which are most resistant to them.
C. CHEMICALS TO BE ESPECIALLY CAUTIOUS WITH
It is particularly important to know which chemical substances may cause chemical burns. The following general list is not meant to be complete. You should make yourself familiar with the compounds listed here as a guide to other specific examples you may encounter.
Caustic Substances That React With Skin
Concentrated Acids Strong Bases
hydrofluoric*, fluorosulfuric* (i) as solids and concentrated aqueous
hydrochloric, hydrobromic, hydroiodic, solutions: hydroxides of sodium, potassium,
sulfuric, nitric, chlorosulfonic, chromic, lithium, ammonia, calcium, strontium, barium
phosphoric, glacial acetic, trichloroacetic (ii) as solids (when mixed with water):
hydrides of sodium, lithium, potassium,
amides of sodium, lithium, potassium;
oxides and peroxides of sodium, lithium,
potassium, calcium, barium
sodium, lithium fluorine*, chlorine
potassium, calcium bromine, iodine, phosphorus
Vesicants Strong Oxidizing Agents
thionyl and sulfuryl chlorides hydrogen peroxide (> 10%)
acid chlorides permanganates, chromates
allylic and benzylic halides dichromates, periodates
reactive alkylating agents persulfates, peracids
(such as dimethyl sulfate, methyl iodide)
phenols, polyhydroxylated aromatics
Strong Reducing Agents Strong Lewis Acids
sodium borohydride boron trihalides
lithium aluminum hydride stannic halides
diborane titanium tetrahalides
diisobutylaluminum hydride arsenic pentahalides
phosphorus trihalides and pentahalides
aluminum halides and alkyls
* See Section E.
D. FIRST AID TREATMENT FOR CHEMICALS ON THE SKIN
While the Emergency Department of MUMC hospital is not far from the Chemistry Department, it is important that first aid measures begin immediately after the skin has been splashed or exposed to a chemical.
First, all solid chemical should be removed from the exposed area. Second, all clothing that was splashed by the chemical should be removed. Third, as soon as possible thereafter, all affected areas should be washed copiously with a gentle flow of water. For hands and arms, washing in the sink will be best. For eyes, use the eyewash fountains near the room exits. For portions of the trunk of the body use the shower near the room exit of each laboratory.
For water lavage to be successful, it must be started as soon as possible after exposure. It has been well documented that lavage begun within the first minute of exposure reduces tissue damage dramatically compared to lavage begun after three minutes. However, much more serious damage can result if this therapy is delayed. For example, when lavage was delayed for one hour following an exposure to sodium hydroxide or for 15 minutes following an exposure to hydrochloric acid, the skin pH could not be brought to normal even by prolonged washing.
It is in your own best interest to clean up the exposed skin rapidly and thoroughly before going to the hospital emergency centre (if still necessary). If such a lavage is not undertaken, the chemical burns sustained during the time needed to walk over to MUMC (assuming you can walk) and before a medic sees you could result in serious damage.
E. HANDLING PROCEDURES AND FIRST AID TREATMENT FOR HF, HS03F AND ANY HF PRECURSORS
Hydrofluoric acid (HF) is a hazardous, highly corrosive acid which can cause severe burns to the skin and eyes; it may be fatal if ingested. HF burns require immediate specialized first aid and medical treatment. The first aid treatment for HF exposure must begin immediately in the lab ‑ it is imperative that all personnel using HF or HSO3F have the knowledge and treatment described below at hand. The dangers of these substances as caustic agents cannot be, and is not underestimated here. A full discussion of hydrofluoric acid burns and their treatment can be found in Reference 18.
The concentration of HF or its vapours dramatically affects the time course of the development of symptoms:
1. Less than 20% HF: may not produce burn symptoms for up to 24 hours
2. 20%‑50% HF: may not produce burn symptoms for 1 to 8 hours.
3. Over 50% HF (including anhydrous HF): usually causes burns with immediate pain and visual indications.
Hydrofluoric acid differs from other caustic acids because it readily penetrates the skin, causing the destruction of deep tissue layers and even bone. Unlike other acids which are rapidly neutralized, this process may continue for several days.
Treatments to stem the destructive effects of HF exposure are directed toward tying up the fluoride ion to reduce its destructive effects. The traditional medical treatment has been a series of subcutaneous (under the skin) injections of a calcium gluconate solution, which sequesters the fluoride ion as calcium fluoride. This painful but effective treatment will probably be unnecessary if you follow the general methods outlined below immediately after skin contact.
First Aid Treatment for HF and HSO3F Burns
1. Wash affected area immediately with copious amounts of cold water for 1‑2 minutes.
2. Make a slush bath of a 10% aqueous tetramethylammonium chloride solution with liquid nitrogen (or with ice) in a wide Dewar flask or a wide beaker.*
3. Bathe the affected area with a J Cloth (or a paper towel) soaked in the cold ammonium salt slush.
4. Continue bathing area for 20‑30 minutes, ensuring that the bath and J Cloth remain cold.
5. Go to MUMC Emergency. Know what first aid treatment has already been administered. In the case of bad burns, subcutaneous injections of calcium gluconate may be required.
6. Follow up treatment: Vitamin A ointment (brand name: A&D ointment).
*In their brochures on HF treatments for skin and eye exposures, Allied Chemical Company recommends the use of polymeric quaternary amines as fluoride ion sequestering reagents. These agents should be kept in any lab or area where HF is used or handled:
(a) HYAMINE 1622 ‑ prepare a 0.2% aqueous solution (1:500 dilution) of benzethonium chloride
(b) ZEPHIRAN ‑ prepare a 0.13% aqueous solution (1:750 dilution) of benzalkonium chloride
For those using HF or wanting more information, a file of documents on HF burn and spill
treatments is available from the Safety Committee.
Some General Procedures for Handling HF and HSO3F
1. Know the proper first aid treatment for burns from these substances. Know the location of the quaternary ammonium halide solutions and ensure that liquid nitrogen is available.
2. Gloves, safety glasses or full face shield, lab coat and rubber apron should be worn.
3. Always have ice available for disposal of any HSO3F waste.
4. Never handle a large amount of either substance when alone in the lab.
5. Always cool samples of HSO3F before opening.
6. All containers, samples, etc., should be clearly labelled and stored safely in the fume hood.
7. Be aware that HF attacks glass readily.
8. Do not store large amounts of HF or HSO3F in round bottom flasks for long periods.
9. Distillation of HSO3F:
(a) Do all distillations in the fume hood with sash down.
(b) Put a sign on fume hood window, warning others.
(c) Clean all equipment immediately after distillation and store distilled acid properly.
10. Sealing samples of HSO3F:
(a) Set up flame in hood
(b) Close door to lab; post a warning sign on outside of door; lock door if necessary.