HYDROFLUOROSILICIC ACID (25% OR LESS)

Colorless to straw yellow liquid with a slightly acrid odor. Transported in special plastic bottles because material attacks glass.

none

Soluble in water.

Excerpt from 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated. For electric vehicles or equipment, 147 (lithium ion batteries) or 138 (sodium batteries) should also be consulted. (ERG, 2020)

Acute contact will cause severe eye and skin burns. Acute vapor exposure may cause eye and skin irritation. Chronic exposure may cause osteofluorosis and respiratory imipairment. (USCG, 1999)

HYDROFLUOROSILICIC ACID (25% OR LESS) can react with strong acids (such as sulfuric acid) to release fumes of toxic hydrogen fluoride. Attacks glass and materials containing silica. Reacts exothermically with chemical bases (examples: amines, amides, inorganic hydroxides). Reacts with active metals, including iron and aluminum to dissolve the metal and liberate hydrogen and/or toxic gases. Can initiate polymerization in certain alkenes. Reacts with cyanide salts and compounds to release gaseous hydrogen cyanide. Flammable and/or toxic gases are also often generated by reactions with dithiocarbamates, isocyanates, mercaptans, nitrides, nitriles, sulfides, and weak or strong reducing agents. Additional gas-generating reactions may occur with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), and carbonates. Can catalyze (increase the rate of) chemical reactions. Decomposes when heated to the boiling point to produce very toxic and corrosive hydrogen fluoride gas.

• Acids, Strong Non-oxidizing
• Fluoride Salts, Soluble
• Water and Aqueous Solutions

Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below.

• Mineral-Based & Clay-Based Absorbents
• Sand
• Dirt/Earth

Excerpt from 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.

FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2020)

Fire Extinguishing Agents Not to Be Used: Avoid direct contact between water and acid.

Fire Extinguishing Agents: Use dry chemical, carbon dioxide or water spray on adjacent fires. (USCG, 1999)

Neutralizing Agents for Acids and Caustics: Lime. (USCG, 1999)

Wear full impervious protective clothing and approved respirator. Where splashing is possible wear full face shield or chemical safety goggles. Use approved respirator to protect against vapors. (USCG, 1999)

Normalized Breakthrough Times (in Minutes)

Chemical	CAS Number	State	QS	QC	SL	C3	TF	TP	RC	TK	RF
Fluorosilicic acid (33-35%)	16961-83-4	Liquid			>480	>480	>480	>480	>480		>480

Special Warning from DuPont: Tychem® and Tyvek® fabrics should not be used around heat, flames, sparks or in potentially flammable or explosive environments. Only...

(DuPont, 2023)

Get medical attention.

INHALATION: Remove to fresh air. If breathing is difficult, give oxygen.

EYES: Flush with water for at least 15 min., lifting lids occasionally.

SKIN: Remove contaminated clothing and shoes. Flush with water.

INGESTION: Dilute with milk, lime water, or aluminum hydroxide. (USCG, 1999)

• FLUOROSILICIC ACID
• FLUOSILICIC ACID
• HFSA
• HYDROFLUOROSILICIC ACID (25% OR LESS)