Hydrofluoric Acid
Awareness Training
Version Jan 2011
Contents
Locations within the School of Engineering
where the use of HF is permitted.
What is HF and why is it harmful?
Medical effects of HF exposure.
Personal Protective Equipment.
First Aid treatment for HF exposure.
Permitted Areas of Use Within the
School
There are only 3 areas within the School that have
been designated for the use of HF.
These are:
SMC Bay 8 and analytical labs
Flemin Jenkins AD Cab lab
In addition, all work may only be undertaken by
competent persons wearing full PPE within a
suitable fume cupboard or wet deck.
What if Hydrofluoric Acid?
Hydrofluoric acid (HF) is a mineral acid, similar to
HCl, H2SO4 or HNO3.
In the acidic solution there are H+ and F- ions.
Like every other mineral acid, HF is corrosive but
unlike the other acids, the most significant risk
results from the toxicity of the F- ions.
HF readily attacks glass so must only be used with
the appropriate beakers, i.e. those made from
materials such as PFA, PE etc.
Medical Effects of HF Exposure
HF is a highly corrosive acid which can severely burn skin,
eyes, and mucous membranes. The vapours from anhydrous
hydrofluoric acid or its concentrated solutions can also burn
these tissues.
HF is similar to other acids in that the initial extent of a burn
depends on the concentration, the temperature, the duration
of contact with the acid and the size of the burn.
Hydrofluoric acid differs, however, from other acids
because the fluoride ion readily penetrates the skin,
causing destruction of deep tissue layers. Unlike other
acids which are rapidly neutralized, this process may
continue for days if left untreated.
From Honeywell’s publication “Recommended Medical Treatment for Hydrofluoric Acid Exposure”, a copy of which can be found on
the SMC wiki and also in the HF burns kit.
Medical Effects of HF Exposure
Strong acid concentrations (over 50%), and particularly
anhydrous HF (AHF or 100% HF), cause immediate, severe,
burning pain and a whitish discoloration of the skin often
followed by blister formation. Skin exposure to HF vapours can
result in similar burns.
HF skin burns are usually accompanied by severe, throbbing
pain which is thought to be due to irritation of nerve endings
by increased levels of potassium ions entering the
extracellular space to compensate for the reduced levels of
calcium ions, which have been bound to the fluoride.
Relief of pain is an important guide to the success of
treatment.
From Honeywell’s publication “Recommended Medical Treatment for Hydrofluoric Acid Exposure”, a copy of which can be found on
the SMC wiki and also in the HF burns kit.
Medical Effects of HF Exposure
The usual initial signs of an HF burn are redness, edema, and
blistering. With more concentrated acids, a blanched white
area appears.
The fluoride ion penetrates the upper layers of the skin. A
thick granular exudate may form under blisters due to
liquefaction necrosis.
In rare (and untreated) cases, there may be penetration to
underlying bone with decalcification.
HF burns require immediate and specialized first aid
and medical treatment differing from the treatment of other
chemical burns.
If untreated or if improperly treated, permanent damage,
disability or death may result. If, however, the burns are
promptly and properly recognized and managed, the results of
treatment are generally favourable.
From Honeywell’s publication “Recommended Medical Treatment for Hydrofluoric Acid Exposure”, a copy of which can be found on
the SMC wiki and also in the HF burns kit.
Personal Protective Equipment
(PPE)
Our philosophy is create a environment in which we minimise
the risk from HF exposure. We have put in place engineering
controls (wet decks and fume cupboards), provided training
(this presentation and other forms) and finally provided PPE
as a last resort.
All users of HF must wear PPE and the following are provided
in the cleanroom.
Full face visor.
Protective apron.
Chemical resistant gloves.
HF Spills
A small spill of HF that is contained within the wet deck can be
simply washed away with water but make sure that all the HF
has been removed.
Larger spills or a spill of any amount of HF outside of the wet
deck should is significant.
In this instance, evacuate the cleanroom by sounding the
“smell bell” located outside bay 8.
If possible open the wet decks to help extract the area.
Contact the technical staff and clean room manager informing
them of the details of the incident.
Do not re-enter the cleanroom until the spill has been dealt
with and the area declared safe.
HF First Aid - General
All exposure to HF should receive immediate first
aid and medical evaluation even if the injury
appears minor or no pain is felt.
All helpers must wear appropriate PPE to avoid
further casualties.
Once first aid has been started, get medical
assistance by calling 2222 from any University
phone.
Do not stop first aid treatment until told to do so by
a medical professional.
HF First Aid – Skin Burns
Immediately place the patient under the safety
shower and wash off the acid. Speed and
thoroughness are paramount.
Arrange for immediate medical treatment by Calling
2222 from any University phone.
Remove any contaminated clothing but do not stop
washing the effected site of the burn with water.
After at least 5 minutes of washing under the safety
shower, apply calcium gluconate gel and massage
into the effected site. Keep applying the gel and
massaging the site until told to stop by the medical
professionals.
HF First Aid – Eye Exposure
Immediately begin to gently flush the eye with
water.
Arrange for immediate medical treatment by Calling
2222 from any university phone.
Remove any contact lenses but don’t interrupt the
flushing.
Hold the eyelids open and away from the eye.
Continue to flush with water for at least 15 minutes
or told to do so by a medical professional.
HF First Aid - Inhalation
Immediately evacuate the patient to an area
of fresh air.
Arrange for immediate medical treatment by
Calling 2222 from any university phone.
Administer medical oxygen if trained to do
so.
HF First Aid - Ingestion
Have the patient drinking large quantities of
milk (preferable) or water to dilute the acid.
Arrange for immediate medical treatment by
Calling 2222 from any university phone.
Do not induce vomiting.
Never give anything my mouth to an
unconscious patient.
First Aid Summary
From Honeywell’s publication “Recommended Medical Treatment for Hydrofluoric Acid Exposure”, a copy of which can be found on
the SMC wiki and also in the HF burns kit.
HF Safety Equipment
There are safety showers located in or adjacent to
all areas in which HF is used.
A HF burns kit has been provided. The kit contains:
• Nitrile protective gloves.
• Calcium gluconate gel
• HF MSDS and the Honeywell publication “Medical
Treatment for Hydrofluroic Acid Exposure” which should
be sent with the patient to hospital.
A medical oxygen kit is located in the changing
room.
Further Training
The next step in the training is to go into
the cleanroom and look at the facilities and
safety systems in place.
Finally instruction will be given in the correct
usage of the wet decks.
Summary
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HF should be treated with the utmost respect.
Always assume the HF bench is contaminated and always
clean up thoroughly after you use it.
Never work alone with HF.
Avoid overcrowding around the area.
Only use the area if absolutely necessary.
Only use polypropylene beakers and utensils with HF.
Use the Calcium glutamate gel if you suspect any type of
contact with HF.
If you use the gel inform and take the tube with you for
further applications.
Familiarise yourself with the first aid procedures as you
may be called upon to assist at any time.