We use formic acid in the Textile Lab I work in- 85% concentration.  (If
I recall correctly- we purchase it in the concentration we use because
handing, diluting and  and rebottling it is too hazardous.)
It is handled only inside a fume hood, and the wearer must have on heavy
gloves, a full length plastic apron, and a full face shield.
    75% formic will dissolve nylon- It can also damage acrylic
and may damage other plastics when concentrated . It is not safe to assume
that all plastics are impervious to all acids-get the wrong types together
and your  containers may break down in contact with the acid.  The chemical
supply houses use special plastics in their chemical handling containers,
and special acid resistant waste
containers are required for safe disposal of waste.
    Formic is <really> nasty stuff- much worse in some ways than sulfuric
acid, which we
use by the gallon.  I have gotten splashed on the arm with 70% sulfuric
acid, and tho I took  my time getting to the sink, felt little discomfort
beyond a slight itching.  The fumes alone of formic acid are enough to cause
my eyes to tear, and my throat to sting.

For more info on acid resistant safely equipment try Fischer scientific
http://www.fishersci.com

They have a full MSDs on formic acid- You should read this if you are
working with the stuff.
Here is a section (Copied directly) of the MSDS:

EMERGENCY OVERVIEW
Appearance: Not available. Flash Point: 69 deg C. Danger! Corrosive.
Harmful. Combustible liquid.Hygroscopic. Heat sensitive. Causes eye and skin
burns. Causesdigestive and respiratory tract burns.
Target Organs: None.

Potential Health Effects

Eye: Causes severe eye burns. May cause conjunctivitis. Lachrymator. Causes
redness and pain. Lachrymator.
Skin: Causes skin burns. Causes redness and pain.
Ingestion: Harmful if swallowed. May cause kidney damage. May cause severe
digestive tract irritation with abdominal pain, nausea, vomiting and
diarrhea. May cause burns to the digestive tract.
Inhalation: May cause irritation of the respiratory tract with burning pain
in the nose and throat, coughing, wheezing, shortness of breath and
pulmonary edema. Causes chemical burns to the respiratory tract.
Chronic: Not available.

Section 4 - First Aid Measures


Eyes: Immediately flush eyes with plenty of water for at least 15 minutes,
occasionally lifting the upper and lower lids. Get medical aid immediately.
Skin: Get medical aid immediately. Immediately flush skin with plenty of
soap and water for at least 15 minutes while removing contaminated clothing
and shoes.
Ingestion: Do NOT induce vomiting. Get medical aid immediately. Wash mouth
out with water. Give milk of magnesia.
Inhalation: Get medical aid immediately. If not breathing, give artificial
respiration. If breathing is difficult, give oxygen.
Notes to Physician: Treat symptomatically and supportively.


Ellen Anglin