Here is an article I received from John AKA: Hot Water Wizard.. Thanks John..
Here is an important Article on Hydroflouric Acid that everyone should
Read.
First Aid for a Unique Acid:
Hydrofluoric Acid
by Eileen B. Segal
This article originally appeared in the January/February 2000 issue
of Chemical Health & Safety. Reprinted with permission.
October 22, 1999: Robert Belk, a 48-year-old business owner, died at
Grady Memorial Hospital after an exposure to hydrofluoric acid. Belk
owned a company called Chemical Packaging near Atlanta, GA, which
produced solutions for high-pressure washing. At the time of the
accident, Belk was mixing a solution when a hose slipped, saturating
his clothes with 70% hydrofluoric acid. He hosed off with water, but
rather than have his secretary call the paramedics, he drove himself
to the hospital. Burns were found on both lower legs and his left
arm, but it was the HF that went through his skin that caused his
death the following day from respiratory and heart failure.1
The above accident illustrates a dire consequence of working with
hydrofluoric acid without an awareness of its extreme hazards and
with a lack of preparedness. From the numerous queries I personally
have received after publication of my first paper in 1998,2 I
conclude that there are still many more who could use information.
And from a recent spate of inquiries on the safety listserve, it
appears that many have not established a protocol for HF exposure or
heard of the current recommended methods of treatment. In this
article, I want to discuss:
I. Review of HF Hazards
II. Emergency Procedures
III. Treatments
IV. 5 vs. 15 Minutes of Irrigation
V. Current Status of Hexafluorine
I. Review of HF Hazards
Hydrofluoric acid (CAS 7664-39-3) is a high-volume chemical used in
at least eight industries (see Fig. 1). It had a production rate of
375,000 tons in 1998, and its U.S. demand is estimated to be 400,000
tons in 2002.3 It is considered more hazardous than most chemicals in
five out of six ranking systems4; and it is ranked as one of the most
hazardous compounds (worst 10%) to human health. Ray Campbell, REA,
CCHO, at Varian, Inc., described his HF injury as "the most painful,
disabling, scarring, long-term injury I have ever seen, and I am a
Vietnam veteran." Concentrated HF covering 2% of the body can be
fatal.
HF is a colorless, fuming liquid or gas with strong, irritating odor.
In concentrated forms it is a strong protonic acid, whereas dilute
solutions are weak acids (pKa = 3) that remain relatively non-ionized
but can penetrate the stratum corneum (the tough waterproof outer
skin layer of dead cells) and penetrate deep into tissue layers.5
Once absorbed, HF dissociates rapidly at the physiological pH of 7.4.
HF ® H+ + F-
Toxic systemic effects occur when the electron-hungry fluoride ion
penetrates and migrates into tissue to bind primarily with calcium,
although binding to magnesium, sodium and potassium can also occur.
Ca2+ + 2F- ® CaF2
Mg2+ + 2F- ® MgF2
Without enough calcium (hypocalcemia) and magnesium (hypomagnesia),
nerves fail and cell membranes collapse. In addition, excess
potassium (hyperkalemia) can occur, which can lead to life-
threatening cardiac arrythmias (ventricular fibrillation). The
adverse effects can progress for several days after exposure.
Surface involvement of weak solutions is minimal and may even be
absent. Burns to the fingers and nail beds may leave the overlying
nails intact. An insidious hazard is the fact that dilute solutions
are indistinguishable from water.
The time to onset of symptoms is related to the concentration of the
HF:
• At concentrations greater than 50%: immediate burns appear with
rapid destruction of tissue as noted by a whitish discoloration,
usually proceeding to blisters, accompanied by severe pain. The pain
is typically described as "deep," "burning" or "throbbing" and is
often out of proportion to apparent skin involvement.
• At concentrations between 20 and 50%: burns can be delayed one to
eight hours.
• At concentrations less than 20%: painful erythema may be delayed
for up to 24 hours. Redness, burning or pain may not show up until
several minutes or even hours have elapsed. Thus, the surface area of
the burn is not predictive of effects.
II. Emergency Procedures
Standard first aid for most corrosives is to flush the exposed area
with water for fifteen minutes. Then treatment by a professional can
be administered. However, because of the dire consequences of HF
exposures, the following first aid is recommended (based mainly on
procedures used by AlliedSignal6).
A. Skin Contact
1. Immediately (within seconds) shower or flush with plenty of water.
2. Remove all clothing while in the shower. (Remove goggles last and
double-bag contaminated clothes.)
3. If 2.5% calcium gluconate gel or 0.13% benzalkonium chloride is
available, rinsing may be limited to five minutes [this is sufficient
time to effectively remove HF from the skin; additional flushing time
is unnecessary and will delay further treatment]. If neither
neutralizing agent is on hand, continue to flush until medical help
is available.
4. Continue with either step a. or b.
a. Apply calcium gluconate gel (2.5%) while wearing impervious
gloves. Massage the gel promptly and repeatedly into burned area
until pain is relieved. If pain does not subside within 20 to 30
minutes, injections of 5% calcium gluconate by a professional may be
needed.
b. Immerse affected area in iced 0.13% benzalkonium chloride
(Zephiran). Use ice cubes, not shaved ice, in order to prevent
frostbite. If immersion is not practical, use towels soaked with iced
0.13 % benzalkonium chloride as compresses for the burned area.
Change compresses every two to four minutes. Continue until pain is
relieved. (This may require hours.)
5. Get medical help.
B. Breathing Vapor
1. Immediately get to fresh air.
2. Call or have someone call a physician.
3. Breathe 100% oxygen (10 to 12 L/min flow rate) as soon as
possible.
4. Trained personnel should provide calcium gluconate (2.5%) by
nebulizer.
5. Get medical attention.
C. Ingestion
1. Drink large amounts of water. Do not induce vomiting or administer
activated charcoal.
2. Drink several glasses of milk or several ounces of Milk of
Magnesia, Mylanta, Maalox or similar product, or eat up to 30 Tums,
Caltrate or other antacid tablet.
3. Get immediate medical attention.
D. Eye Contact
Because of the ability of HF to penetrate deep into tissue, exposure
of HF solution or vapor to the eye can produce more extensive damage
than that of other acids in similar concentrations. For example,
hydrochloric acid damages only the superficial structures of the eye
because its penetration is limited by a precipitated protein
barrier.5 In the case of HF, immediate action should be taken with
initial flushing and then treatment with sterile 1% calcium gluconate
solution. For details, see the inset by Bernard Blais, M.D.
III. Treatments
Calcium gluconate is the preferred treatment of choice for minor HF
exposure for the following reasons:
• It is easy to use.
• It can be self-administered or applied by personnel trained in
first aid care.
• It can be applied immediately as soon as the burn is suspected.
• It is painless to apply.
• It produces no risk of increasing tension in the tissues.
• It can be used topically, opthalmically, by infiltration and
inhalation.
• It reduces the risk of hypocalcemia.
• No sophisticated equipment is necessary.
Pharmascience Inc. is the main supplier of calcium gluconate and can
be contacted at 8400 Darnley Rd., Montreal, Quebec strongT 1M4,
Canada. In the U.S., the company has a distributor at 175 Rano St.,
Buffalo, NY 14207 (800-207-4477, orders; 800-363-8805, technical
information).
A. Mixing Your Own Solutions
This method can be considerably cheaper or a local pharmacy can make
up a solution.
1. Topical Gel (2.5%). Mix one 10-mL ampule (10%) per ounce of
surgical gel (K-Y Lubricating Jelly; Johnson and Johnson). The gel
must be kept above 40°F. Do not freeze.
The latest DuPont MSDS (Nov 1998) supplies another formulation as
well: Mix 3.5 g of USP calcium gluconate powder with a 5-oz. tube of
surgical water-soluble lubricant (e.g., K-Y Lubricating Jelly).
2. Calcium Gluconate Solutions for Topical Injections. Mix one 10-mL
ampule (10%) with an equal amount of saline solution to give a 5%
calcium gluconate concentrate.
3. Nebulizer. Mix one 10-mL ampule (10%) per 30 mL of saline solution
to give a 2.5% calcium gluconate solution.
4. Eye Wash. Mix one 10-mL ampule (10%) per 90 mL of saline to get a
1% calcium gluconate solution. If you take 100 mL out of a 1000-mL
bag of normal saline and put in 100 mL of calcium gluconate, you will
have the proper mixture.
Note: The shelf-life for all mixtures has not been determined, but a
periodic replacement period should be established; the recommendation
on the DuPont MSDS is six months. If the ingredients are stored
separately until needed, the shelf-life is less of a concern.
Be aware that even following emergency treatment with calcium
gluconate, delayed life-threatening burns can still occur. Follow up
treatment at a medical facility is necessary. It is wise to warn the
hospital of your intentions to bring folks to them for HF burn
treatment and to make sure that they are informed of its specific
treatment.
B. Benzalkonium Chloride
(Zephiran Solution)
This product can be obtained from Sanofi Inc., 90 Park Ave., New
York, NY 10016 (800-446-6267). It is available in gallon containers
as a 1:750 (0.13%) solution. The material has a limited shelf life
and should be stored in light-resistant containers. A 17% solution is
also available but should only be diluted by a qualified individual.
Since benzalkonium chloride is a nonprescription drug, it should be
available through most local pharmacies. They can obtain it from
pharmaceutical wholesale distributors. Assorted basins should be kept
on hand for immersions.
IV. Five vs. 15 Minutes of Irrigation
After my first paper was published,2 a letter to the editor was
published in the Jan./Feb. 1999 issue of Chemical Health & Safety
entitled, "Another viewpoint on the treatment of HF skin exposure."7
The purpose of this letter was to "provide an interpretation of these
different procedures and offer a practical response for HF skin
procedure." Points brought out follow:
• It is straightforward to train employees in a single emergency
response treatment (i.e., the common 15-minute wash protocol).
• Recommendations in MSDSs are inconsistent.
• There is a real possibility that a confused employee will attempt
to apply HF treatment to another acid, (e.g., HCl).
• Community-involvement programs stress communication with industrial
users of HF and hospitals.
All the above are valid statements, but we are faced with a dilemma
when considering DuPont's claim, "Flushing with water thoroughly for
five-minutes is sufficient to effectively remove HF from skin.
Additional flushing time is unnecessary and will delay further
treatment. Although flushing is effective in removing surface acid,
it does not affect the F- that may have already penetrated."
Will an exception to the rule for HF cause confusion? The solution
is, of course, to have a plan in effect ahead of time and to provide
training to implement that plan. All potentially exposed personnel
should be trained in first-aid care for HF burns before beginning
work with HF. Calcium gluconate gel should be readily accessible in
areas where HF exposure potential exists.
DuPont provides all its potentially exposed personnel with a 3" x 5"
booklet and a 2.25" x 3.75" card that is easily carried on their
persons. These are routinely provided free of charge to companies
purchasing HF and to anyone who requests a single copy. (Call 800-441-
9408.)
My contact at DuPont informed me that the five-minute wash procedure
began in 1990 and since that time at least 75% (it might be as high
as 98%) of companies using anhydrous HF have adopted the five-minute
wash. Further, he tells me that the five-minute wash is being applied
to other water-soluble substances such as hydrochloric acid and
chlorine. For skin contact, the DuPont MSDSs for hydrochloric acid
and chlorine state, "Flush the skin thoroughly with water at least
five minutes." Preliminary tests show that the five-minute time frame
is effective in many cases; this is especially fortuitous in cold
areas where a 15-minute cold shower wreaks its own hazards.
And consider this! In 1998, Pharmascience introduced a new product, a
sterile 2.5% isotonic calcium gluconate wash packaged in a plastic
container (480mL). In the event of an exposure, the solution was to
be applied immediately to affected areas until thoroughly washed. It
was claimed that the wash removed more HF than a pure water wash and
significantly reduced the quantity of HF that penetrated the skin.
After washing, calcium gluconate gel was to be applied repeatedly
while seeking medical attention. Evidently, HF users weren't ready
for this innovation and, as of August 6, 1999, the wash was no longer
available.
V. Current Status of Hexafluorine
At the 1998 spring meeting of the Semiconductor Safety Association,
Alan Hall, M.D., delivered a paper 8 that presented impressive
results about the use of Hexafluorine, a proprietary product
manufactured by Laboratoire PREVOR in France. This product is claimed
to be an amphoteric, hypertonic, chelating agent specifically
designed to detoxify hydrofluoric acid. It has chemical bond energy
greater than that of eye/skin receptors and does not produce a
significant exothermic reaction with release of heat that could
further damage exposed tissue. In addition, it is claimed to be safe
to use in the eyes. Hall describes five cases in his paper. Two of
the cases follow:
1. A worker fell into a bath containing 1505 L of water, 30 L of
concentrated hydrochloric acid and 233 L of 59% HF (calculated bath
concentration — 9.2% HF), immersing his entire body and face.
Hexafluorine, as well as a regular water eyewash, was immediately
used for decontamination by coworkers. Only minor burns developed on
the back and abdomen. There was a significant corneal burn of the
left eye, but the right eye remained normal.
2. At a facility using a chemical dipping bath containing nitric acid
and HF for producing stainless steel for construction and machine
tools, a worker sustained an eye splash with 38% HF. He rinsed his
eye immediately with Hexafluorine and did not develop any eye injury,
returning to work the next day.
Experimental animal data on rats and rabbits as well as in vitro data
are compelling. One such case is shown in Fig. 2. To simulate the
effects of decontamination without flushing, 10 mL of 0.1 N HF (0.2%)
was placed in a beaker and either water, 10% calcium gluconate or
Hexafluorine was added. The pH and the pF (pF = negative logarithm of
the fluoride ion concentration) were measured. As noted, water had
little effect. Both calcium gluconate and Hexafluorine absorbed or
neutralized H+, although Hexafluorine bound the hydrogen ion 100
times greater than calcium gluconate. The final pH for Hexafluorine
was 6.5 vs. 4.5 (still acidic) for calcium gluconate.
I recently spoke with Dr. Hall, one of the authors of the 1998 paper
on Hexafluorine, who has been hired as a consultant for PREVOR. He
was very skeptical about the product at the beginning, but new
incidents of 11 exposed workers at Mannesmann AG (headquartered in
Dusseldorf, Germany) have shown the effectiveness of the product.
These case studies were presented at the Semiconductor Safety
Association 2000 Spring Meeting and published.
Hexafluorine is being widely used in France and Germany. Ireland,
Italy, Sweden and the United Kingdom are giving serious consideration
to its use. In the U.S., PREVOR is actively seeking FDA approval,
armed with the new compelling data from Germany. One "sticky" issue
is whether the product should be considered a drug or, preferably, a
medical device (as it is in Europe).
Conclusion
Because HF is a unique acid and its emergency treatment is
specialized and different from that of other inorganic acids, all
exposed and potentially exposed personnel should be made familiar
with its properties and hazards and trained ahead of time to deal
with emergency situations. In the case of the HF fatality mentioned
in the introductory news report, the victim evidently was not aware
of the internal damage that the fluoride ion could inflict. Protocols
should be set up, appropriate supplies should be on hand and
arrangements should be made with nearby hospitals and professionals
because not all physicians may be aware of the unique treatments. In
addition, one should always try to keep up to date to learn of new
innovations in safety, especially when working with nasty chemicals,
such as HF, and then institute those changes if they can save lives.
Even if you've already converted to a five-minute rinse and have
calcium gluconate on hand, don't get complacent! New and better
changes may be coming. Stay on top of safety!
Acknowledgements
I want to thank Dr. Bernard Blais for his contribution to this
article and acknowledge Allied and DuPont for their valuable
comments, assistance and generosity in sharing information.
References
1. Kelley, S. The Gwinnett Daily Post, Oct. 23, 1999, p.1. Web site:
http://www.gwinnetdailypost.com/gdp1...pals2-gdp.htm.
2. Segal, E.B. "First Aid for a Unique Acid: HF," Chem. Health Saf.
1998, 5, 25-28. Also on the Web:
http://dchas.cehs.siu.edu/Magazine/hf.
3. "Chemical Market Reporter," Chemical Profile of Hydrofluoric Acid,
Oct. 1999. Schnell Publishing, New York, NY.
4. Chemical Scoreboard, Environmental Defense Fund, New York, NY,
1999.
5. Caravati, E.M., Am. J. Emerg. Med. 1988, 6(2), 143.
6. "Recommended Medical Treatment for Hydrofluoric Acid Exposure,"
Dec. 1998, AlliedSignal Inc., P.O. Box 1053, 101 Columbia Rd.,
Morristown, NJ 07962-1053. This booklet can be obtained at no charge
by calling 800-622-5002 or faxing your request to 973-455-6141. For
more information, check out AlliedSignal's Web site at
http://www.specialtychem.com/ha/.
7. Langerman, N. Chem. Health Saf. 1999, 6(1), 5.
8. Hall, A. H.; Blomet, J.: Gross, M.: Nehles, J. "Hexafluorine® for
Emergency Decontamination of Hydrofluoric Acid (HF) Eye/Skin
Splashes." Presented at the Semiconductor Safety Association Meeting,
San Diego, CA, March 1999. Funded by Laboratoire PREVOR, Moulin de
Verville, Valmondois, France.
Eileen B. Segal is a private consultant in the field of chemical
health and safety and in technical editing. She was an analytical
chemist for DuPont and the GAF Corp., and for the past 19 years has
conducted seminars in health and safety throughout the United States
and Canada as part of the J.T. Baker Office of Training Services.
Tables:
Hydrofluoric Acid
CAS No. 7664-39-3
UN 1052 (anhydrous)
UN 1790 (solution)
Synonyms: hydrogen fluoride, fluoric acid, hydrofluoride, fluorine
monohydride
OSHA PEL 3 ppm
Description: colorless gas or fuming liquid
Disagreeable, pungent odor at less than 1 ppm
Irritation of eyes and throat at 3 ppm
Molecular weight: 20.0 daltons
Boiling point 68°F (20°C) at 760 mmHg
Specific gravity 0.99 at 19°F (-7°C)
Vapor pressure 400 mmHg (34°F)
Vapor density 0.7 (air=1)
Miscible with water with release of heat
Nonflammable
Industry Use
Electroplating Acid Metal Cleaners — Oxide Removers
Etching Glass Etching and Frosting
Flotation Agents Depressants — Nonsulfide Ores
Integrated Iron and Steel Manufacturing Pickling Acids
Laboratory Chemicals Acids, Other Chemicals (non-salts)
Oil Refineries Catalyst to Produce High-Octane Fuel Additives
Refrigeration Manufacture of Fluorocarbons
Semiconductors Wet Chemical Etching
Home Use: Air conditioning unit coil cleaners; aluminum automotive
wheel cleaners; chrome, brass and crystal cleaners; masonry cleaners;
rust stain remover; truck and commercial car washing compounds; water
spot remover.
Hydroflouric Acid --- A MUST READ!
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