Ammonia solution (35%) COSHH assessment guide

Strong ammonia solution is used in industrial cleaning and laboratory work. At 35% it causes severe burns, its vapour irritates the airways, and it is toxic to aquatic life.

Taken from the Ammonia solution S.G. 0.88 (35%) safety data sheet from Fisher Scientific UK, revision 19 October 2023. Open the data sheet. Formulas differ between products, so check against the sheet for the product you actually buy. This is a laboratory-grade sheet. Trade products sold under the same name can have a different strength and different hazards. Household ammonia is far weaker. Section 2.1 of this sheet lists aquatic hazards H400 and H411, while its label prints H410. Either way, keep it out of drains.

Hazards on the data sheet

Signal word: Danger.

H314 Causes severe skin burns and eye damage
H335 May cause respiratory irritation
H410 Very toxic to aquatic life with long lasting effects

Precautions

P280 Wear protective gloves/protective clothing/eye protection/face protection
P301 + P330 + P331 IF SWALLOWED: Rinse mouth. Do NOT induce vomiting
P303 + P361 + P353 IF ON SKIN (or hair): Take off immediately all contaminated clothing. Rinse skin with water or shower
P304 + P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing
P305 + P351 + P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing
P310 Immediately call a POISON CENTER or doctor/physician

Workplace exposure limit

Long-term (8-hour): 25 ppm or 18 mg/m³. Short-term (15-minute): 35 ppm or 25 mg/m³. EH40/2005 Table 1 lists these figures under ammonia, anhydrous, and has no entry for the solution. This sheet applies the same figures to its ammonia content.

PPE

Eyes	Goggles (European standard - EN 166).
Hands	Protective gloves. All > 480 minutes, EN 374 (minimum requirement): Butyl rubber 0.5 mm, Viton (R) 0.4 mm, Neoprene 0.45 mm.
Breathing	Certified respirators when facing concentrations above the exposure limit. Large scale/emergency: Inorganic gases and vapours filter Type B Grey or Ammonia and organic ammonia derivatives filter Type K Green conforming to EN14387. Small scale/laboratory: EN 149:2001 approved respirator; half mask EN405, or EN140 plus filter EN 141.
Skin	Long sleeved clothing.

First aid

Eyes	Rinse immediately with plenty of water, also under the eyelids, for at least 15 minutes. Keep eye wide open while rinsing. Immediate medical attention is required.
Skin	Wash off immediately with plenty of water for at least 15 minutes. Remove and wash contaminated clothing and gloves, including the inside, before re-use. Call a physician immediately.
Breathed in	If breathing is difficult, give oxygen. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; use a pocket mask with a one-way valve or other proper respiratory medical device. Remove from exposure, lie down. Call a physician immediately.
Swallowed	Do NOT induce vomiting. Never give anything by mouth to an unconscious person. Clean mouth with water. Call a physician immediately.

Storage, spills and what to keep it away from

Storage	Keep containers tightly closed in a dry, cool and well-ventilated place. Corrosives area. Contents may develop pressure upon prolonged storage.
Spills	Evacuate personnel to safe areas and keep people away from and upwind of spill/leak. Ensure adequate ventilation. Soak up with inert absorbent material; keep in suitable, closed containers for disposal. After cleaning, flush away traces with water. Prevent product from entering drains; advise local authorities if significant spillages cannot be contained.
Keep away from	Strong oxidizing agents. Acids. Metals. Aluminium. Zinc. copper. Copper alloys. Fluorine. Halogens.

What your assessment still has to cover

The sheet warns that containers can build up pressure, so record how they are stored and opened. Note the ventilation where it is used, how spills are kept from drains, and whether bleach is on site: the bleach sheet lists ammonia as a material to avoid.

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