Occup. Med. Vol. 46. No. 4, pp. 3 1 3 - 3 1 7 , 1 9 9 6
Copyrights 1996 Rapid Science Publishers for SOM
Printed in Great Britain. All rights reserved
0962-7480/96
The treatment of hydrofluoric
acid burns
K. Matsuno
Department of Environmental Health, School of Medicine, University
of Occupational and Environmental Health, Japan
Hydrofluoric acid is a colourless or almost colourless, fuming liquid having a highly
caustic and corrosive effect on organic tissue. Many kinds of hydrofluoric acid in
concentrations are used in industrial processes and laboratory uses because of its
useful chemical properties. Hydrofluoric acid causes severe and painful burns to the
skin and eyes. In this paper, the immediate symptoms, the typical treatments in the
literature, first aid and therapy of hydrofluoric acid burns are reviewed.
Occup. Mod. Vol. 46, 313-317,1996
Received 21 April 1995;accefted in final form IS June 1996.
GENERAL PROPERTIES AND USES OF
HYDROGEN FLUORIDE AND
HYDROFLUORIC ACID
Hydrofluoric acid is an aqueous solution of hydrogen
fluoride. Hydrogen fluoride is a colorless, fuming liquid
or gas with a strong and irritating odor, and is corrosive. The chemical properties are listed in Table 1.
The 38.2 w/w% solution is a binary azeotrope and
its boiling point is 112.2°C. Hydrofluoric acid is usually marketed in concentrations of about 46% and 53%
for laboratory uses. Many kinds of hydrofluoric acid
in concentrations of less than 20%, intermediate solutions, and concentrated solutions of more than 70%
are used in industrial processes because of its useful
chemical properties. Hydrofluoric acid attacks glass or
stone and dissolves silica, and must be kept in plastic,
lead, wax or paraffin paper bottles. It is a strong acid
having a highly caustic and corrosive effect on organic
tissue.
Hydrofluoric acid is used for frosting, etching and
polishing glass, for removing sand from metal castings,
and for etching silicon wafers in many industrial processes, especially in the manufacture of semiconductors
(Table 2). Hydrofluoric acid may be used as a dilute
3% solution at the etch-station, or a 50% solution in
a quartz furnace cleaning operation.
Correspondence and reprint requests to: K. Matsuno, Department of
Environmental Health, School of Medicine, University of Occupational
and Environmental Health, 1-1 Iseigaoka, Yahata-nichiku, Kitakyushu,
807 Japan.
Hydrofluoric acid burns
Hydrofluoric acid causes severe and painful burns to
the skin and eyes. Acid burns to the hand are usually
caused by splashes, holes in gloves or accidental use
of hydrofluoric acid. Burns on the face or other parts
of the body also result from splashing or accidents.
The severity of the burns depends on the concentration
of hydrofluoric acid and the duration of exposure.
Workers using hydrofluoric acid have to handle it with
care to avoid burns and also to avoid inhaling the
vapors.
Skin contact
Hydrofluoric acid in contact with the skin results in
marked tissue destruction. Undissolved hydrogen fluoride rapidly penetrates the skin and the fluoride ion
that reaches the deep tissues causes necrosis of soft
tissues, tendinitis, tenosynovitis or decalcification of
bone.1"6 The bone destruction is extremely painful.
Fluoride ion also attacks enzymes and cell membranes,
and the tissue destruction and neutralization of the
hydrofluoric acid is prolonged for days in contrast to
other acids.3"5 Even a relatively mild exposure to
hydrofluoric acid can often cause a serious bum.
A skin burn from contact with diluted solutions of
less than 20% is characterized by pain and erythema
with a latent period of about 24 hours. Delay of
recognition of contact with diluted solutions often
results in more severe burns because of the delay in
washing or irrigation.2 The pain and erythema of the
skin burn from contact with 20-50% solutions becomes
apparent 1-8 hours after the exposure. When contact
is made with concentrated solutions of above 50%,
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Key words: Burns; first aid; hydrofluoric acid; therapy; treatment.
Table 1. Chemical properties of hydrogen fluoride
Molecular weight
F
H
Boiling point
Hazardous substance (EPA)
Hazardous waste (EPA)
20.01
94.96%
5.04%
19-20°C
Table 2. Uses of hydrofluoric acid
Cleaning cast iron, copper or brass
Removing efflorescence from brick and stone
Removing sand particles from metallic castings
Frosting and etching glass or enamel
Polishing crystal glass
Decomposing cellulose
Enameling and galvanizing iron
Increasing the porosity of ceramics
Analytical work to determine SiC-2
Skin contact
1. Burning sensation and inflammation
2. Irreparable damage to skin, which gradually turns white
and becomse very painful
3. Blisters
4. Profound damage to the tissues
5. Shock may occur as a result of pain
a. weak and rapid pulse
b. cold sweat—pale complexion
c. tendency to fainting
d. cold hands and feet
immediate pain and tissue destruction is apparent.3
There are various kinds of symptoms depending on
the severity of the burn such as erythema alone, central
blanching with peripheral erythema, swelling,
vesiculation, serious burns, ulceration, blue-grey
discoloration and necrosis.2'7 Systematic fluorosis may
also occur with larger burns.
Table 3 shows the immediate symptoms of the skin
burns from contact with hydrofluoric acid as sum
marized by M. J. Lefevre.8
Eye contact
Exposure to hydrofluoric acid in liquid or vapor form
causes severe irritation or injuries to the eyes and
eyelids. The injuries may result in prolonged or
permanent visual defects or total loss of sight. Table 4
shows the immediate symptoms of the eye contact with
hydrofluoric acid as summarized by M. J. Lefevre.9
Eye contact
1. Intense stinging and burning sensation
2. Watering of eyes
3. Conjunctivitis (inflammation of eyes)
4. Burning sensation in eyelids and eyes, with ulceration of
the tissues
5. Irreparable damage to cornea
6. Loss of vision
hydrofluoric acid burns in the literature.3'4'10"19
Traditionally, hydrogen fluoride paste containing
magnesium oxide had been used for the treatment of
hydrofluoric acid burns, but today it is rarely used.
The topical application of a magnesium oxide paste10
or an injection of magnesium compounds, such as
magnesium sulfate, magnesium acetate15 was applied
to the skin.
The quaternary ammonium compounds, 4 benzethonium chloride (Hyamine) solution, 3 ' 4 or
benzalkonium chloride (Zephiran),3'4 are also used for
the treatment of hydrofluoric acid burns. The quaternary ammonium compounds may have the effect of
replacing fluoride ion and the chloride moiety in the
ammonium complex, but the protection mechanism is
not well known. The solutions are often used as an
iced solution to decrease lymphatic spread of the
hydrofluoric acid. The hyamine might cause the
alteration of cellular permeability of the fluoride ion.
The disadvantage of hyamine therapy is that it requires
a prolonged period of saturation of the burn area.2
Iced alcohol is also often coadministered to withdraw
some of the fluoride from the tissues.
It has long been recognized that the infiltration of
calcium gluconate3'10'11'13'15'16 is effective for the treatment of hydrofluoric acid burns. This therapy restrains
the degree of edema or necrosis by hydrofluoric acid
and prevents the penetration of fluoride ion to deeper
tissues. Depending on the case, the intra-arterial
infusion of calcium gluconate10 can be used to deliver
the calcium to the tissues without some of the deleterious local effects.
Recendy, calcium gluconate gel14-17-18'19 has been used
widely in first aid for hydrofluoric acid burns. After
washing off the exposed area, the gel is applied to the
skin to keep the injury minimal.
There is no clear evidence which treatment is best,
because the majority of the literature has been anecdotal or retrospective studies.
FIRST AID AND THERAPY
TREATMENT OF HYDROFLUORIC ACID BURNS
Several treatments have been reported since the early
20th century. Table 5 shows typical treatments of
In the treatment of hydrofluoric acid burns, to prevent
the hydrofluoric acid from fully reacting on tissue
components and causing toxicity to the cell, the
immediate dilution and decontamination of the
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Table 3. Immediate symptoms In an hydrofluoric acid accident8
Table 4. Immediate symptoms in an hydrofluoric acid accident9
K. Matsuno: The treatment ol hydrofluoric acid burns
315
Table 5. Treatment for hydrofluoric acid burns in the literature
Author
Jones (1939)
Treatment
10
Immediate washing with a warm solution of sodium bicarbonate
+ Infiltration with calcium gluconate,
+ Topical application of a magnesium oxide paste
Intravenous calcium gluconate
Paley and Seifter (1941)"
Reinhardt et al. (1965)
Scharnweber (1969)
4
12
Dibbell et al. (1970) 3
3% calcium gluconate infiltration (experiments with rats)
Quaternary ammonium compounds: Hyamine solution, Benzalkonium chloride (Zephiran)
Immediate excision of the wound and closure
Hyamine solution for exposures to solutions of less than 20%,
Benzalkonium chloride (Zephiran) for exposures to solutions of less than 20%,
Calcium gluconate infiltration for exposures to solutions of 20% or greater
Iverson et al. (1971) 1
Infiltration of the bum area with calcium gluconate
Browne (1974) 14
Gel containing 2.5% calcium gluconate
Harris et al. (1981) 15
Injection of calcium gluconate, magnesium sulfate, magnesium acetate
Intra-arterial regional perfusion,
Infiltration of the calcium gluconate
Velvert (1983) 16
Kodama et al. (1988)
Kono et al. (1994) 19
Calcium gluconate gel
18
2.5% calcium gluconate gel
Calcium gluconate jelly
exposed area is most important. The cytotoxic reaction
of hydrofluoric acid is critical. A patient exposed to a
concentrated solution of more than 50% and with a
burn area of over 1-2% of the body surface should
be monitored carefully.
If a worker has come in contact with hydrofluoric
acid, it is essential that the exposed area be washed
immediately with large quantities of water for a sufficient period of time, that is, at least 10-15 minutes.
After the initial decontamination, a topical modality is
applied. The topical therapy is usually adequate for
minor exposure of the skin to a diluted solution of
less than 20% without calcium gluconate infiltration.
If there is erythema, discoloration, severe pain or a
delay of decontamination, calcium gluconate infiltration will be needed in addition to the topical therapy.
However, this is not a fixed rule.
Topical modality
Topical modality should be applied as soon as possible
after washing. A delay may cause the diminishment of
the effect of the topical agent.
There is still a controversy as to the agent of choice
for topical application. Iced solutions of the quaternary
ammonium compounds, 0.13% benzalkonium chloride
(Zephiran) or 0.2% b e n z e t h o n i u m chloride
(Hyamine), a solution of 25% magnesium sulfate (Epsom salts) or a solution of calcium gluconate may be
applied to the exposed area in topical therapy. However, calcium gluconate has been the most widely used
among them. Calcium gluconate gel is also acceptable
for topical therapy. The 2.5% calcium gluconate gel is
easily massaged into the burned area. A patient may
take the gel with him and repeat the application as
needed at home. The burned area should be dressed
in a soft and bulky dressing and observed carefully
for the next 2 days. If the concentration of hydrofluoric
acid is less than 20% and the pain is not too severe,
iced topical treatments need not be applied beyond
1-4 hours.2'7
Calcium gluconate infiltration
If the above topical therapy fails to reduce the pain
caused by the hydrofluoric acid burn within 0.5-1
hour, an injection of 5-10% calcium gluconate should
be considered. Similarly, if the injury appears to be
severe and there is acute pain, this treatment should
be applied to the painful area. The smallest effective
amount of calcium gluconate injected can be determined by monitoring the patient's pain, as the relief
of pain is often a good indication of the end point of
the infiltration. An effective dose of calcium gluconate
is about 0.5 mL/cm2 of the burned surface area,2 and
repeated injections are preferable. More than 0.5 mL/
phalanx of calcium gluconate should not be injected
for finger burns. Basically, local anesthesia should be
avoided in this therapy, to allow the patient to accurately recognize the areas requiring treatment. The
calcium gluconate should be directly infiltrated by a
25- to 30-gauge needle into the affected derma or
subcutanious tissue using a similar technique to a local
anesthesia. The infiltration should be carried out 0.5cm
away from the margin of the injured area into the
surrounding normal area. If the pain recurs, additional
calcium gluconate should be injected. However, the
use of large amounts of calcium gluconate may result
in hypercalcemia. After the calcium gluconate infiltration, the injured area may be carefully debridged. The
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Bracken (1985)
Table 6. First aid manual for hydrofluoric acid accident20
SKIN CONTACT
1. Remove the victim from the source of contamination and take him immediately to the nearest shower.
2. First aiders, wearing rubber gloves and air-tight safety goggles, should remove the clothing from affected area under the
shower (clothing should be cut away, if necessary). Care should be taken not to contaminate healthy skin or eyes. If the victim
is already wearing air-tight safety goggles, do not remove them.
3. Wash him down with cold water for 15 minutes or longer.
4. Dry the skin very gently with a clean, soft towel.
5. Apply 2.5% of calcium gluconate gel on the affected skin.
6. Massage the gel gently into every burnt area with clean fingers.
7. Dress the victim in clean clothes.
In the case of bums (inflammation, blisters, or painful lesions) and in the absence of a physician:
8. If there is no calcium giuconate gel on hand, rub a clean tube of ice on the painful area and apply a dry, sterile dressing.
9. Take the victim, wrapped in a blanket, to the hospital as soon as possible.
If the victim shows signs of shock:
10. Cover him with a blanket.
11. Make him lie down in a quiet place on his back with his head down and legs raised until physician arrives.
b. In the case of extensive splashing of the hydrofluoric acid, wash the victim down under a cold shower or a hand-held hose, at
the same time protecting his eyes.
c. First aider must take precautions for their own safety when handling contaminated clothing.
d. Notify a physician and inform him of the nature of the hydrofluoric acid of the accident.
e. Never apply an oily substance on the affected area without medical advice.
f. Oral administration of 6 tablets of effervescent calcium gluconate (Calciofon, Calglucon, Ebucim, Glucal, and Glubiogen tablets)
dissolved in water is recommended in case of large burns.
EYE CONTACT (Splashing of liquid in or contact of vapor with eyes)
1. Remove the victim from the source of contamination and take him to the nearest eye wash basin or shower.
2. Immediately wipe away any excess chemical very gently and quickly.
3. Wash affected eye or eyes under slowly running water for 15 minutes or longer, making sure that victim's eyelids are held
wide apart and he moves his eyes slowly in every direction.
4. If great pain persists after washing, the nurse can put 1 to 2 drops of anesthetizing eye salve, or better still, 1 drop of benoxinate
(novesine) at 0.4%, into the eye.
5. If the pain still persists, repeat washing the eye for 15 minutes or until the pain is relieved or the pH of the eye retums to normal
(touch the white of the eye with litmus paper)
Notes
a. It is imperative to bathe the eyes as' soon as possible.
b. Never introduce oil or ointment into the eyes without medical advice.
c. Notify a physician and inform him of the name of the chemical and nature of the accident.
d. The medical service will refer the victim to an ophthalmologist and inform him of the nature of the accident and hydrofluoric add.
patient who has to receive a debridgement should be
hospitalized. In case of serious subungual exposure,
the fingernails may be removed.
Intra-arterial infusion of calcium gluconate
Regional intra-arterial infusion of calcium gluconate
is used for serious hydrofluoric burns as an investigational therapy. This therapy can avoid local tissue
distention by subcutaneous infiltration, however, it
should be done only by expert physicians of hydrofluoric acid burns. There is no clear protocol because
of too few cases in which it has been applied. Vervart16
reported a 4-hour infusion of 20% calcium gluconate
for injuries to the hand. Hypercalemia may occur when
calcium gluconate therapy is used.
Finally, Table 6 shows the First Aid Manual for
Hydrofluoric Acid Accident as summarized by M. J.
Lefevre.20
REFERENCES
1. Proctor NH, Hughes JP, Fischman ML, Hathaway GW. The
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Notes
a. It is vital to apply first aid without delay.
K. Matsuno: The treatment of hydrofluoric acid bums
2.
3.
4.
5.
6.
7.
8.
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