- Methyl aldehyde
Clear, colorless liquid with a pungent odor.
Bactericide, fungicide, chemical synthesis
Registry Numbers and Inventories.
EC Index Number
Carcinogenic Category 3; Toxic; Corrosive; Sensitising
R 23/24/25 34 40 43
S 26 36/37 45 51
Agricultural Chemical and Pesticide; Tumorigen; Mutagen; Reproductive Effector; Human Data; Primary Irritant
Swiss Giftliste 1
Japan ENCS (MITI)
Melting point, °C
Boiling point, °C
Vapor pressure, mmHg
664 (-22 C)
Vapor density (air=1)
Odor Threshold Odor threshold 0.5 To 1.0 ppm
0.8153 g/cm3 (-20 C)
Solubility in water
Partition coefficient, pKow
Heat of vaporization
Hazards and Protection.
Keep in a cool, dry, dark location in a tightly sealed container or cylinder. Keep away from incompatible materials, ignition sources and untrained individuals. Secure and label area. Protect containers/cylinders from physical damage.
All chemicals should be considered hazardous. Avoid direct physical contact. Use appropriate, approved safety equipment. Untrained individuals should not handle this chemical or its container. Handling should occur in a chemical fume hood.
Wear appropriate protective gloves, clothing and goggles.
A full facepiece respirator with a formaldehyde cartridge may be worn up to 50 times the exposure limit or the maximum use concentration specified by the appropriate regulatory agency or respirator supplier, whichever is lowest. For emergencies or instances where the exposure levels are not known, use a full-facepiece positive-pressure, air-supplied respirator.
Attempt to stop leak if without undue personnel hazard. Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Apply water spray or mist to knock down vapors. Land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. Dike surface flow using soil, sand bags, foamed polyurethane, or foamed concrete. Absorb bulk liquid with fly ash, cement powder, or commercial sorbents. Water spill: Use natural barriers or oil spill control booms to limit spill travel. Remove trapped material with suction hoses.
Stable - solutions can explode when temperature is elevated. In the region of 180 C the reaction with nitrogen dioxide becomes explosive. vapor explosion hazard indoors, outdoors, or in sewers. Runoff to sewer may create fire or explosion hazard.
Incompatible with oxidizing agents and alkalis. Reacts explosively with nitrogen dioxide at about 180 C. Reacts violently with perchloric acid, perchloric acid-aniline mixtures, and nitromethane. Reaction with hydrochloric acid may form bis-chloromethyl ether, an OSHA regulated carcinogen.
Upper exp. limit, %
Lower exp. limit, %
In the event of a fire, wear full protective clothing and NIOSH-approved self-contained breathing apparatus with full facepiece operated in the pressure demand or other positive pressure mode. Water may be used to flush spills away from exposures and to dilute spills to non-flammable mixtures. Extinguish using water spray, dry chemical, alcohol foam, or carbon dioxide.
Flammable liquid and vapor. Formaldehyde vaporizes readily from solution and is flammable in air.
Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers.
Fire will produce irritating, corrosive and/or toxic gases.
NIOSH REL: Ca TWA 0.016 ppm C 0.1 ppm [15-minute] See Appendix A OSHA PEL: [1910.1048] TWA 0.75 ppm ST 2 ppm IDLH Ca [20 ppm]
O, G-A2, I-2A, N-2, CP65
Frequent or prolonged exposure to formaldehyde may cause hypersensitivity leading to contact dermatitis. Repeated or prolonged skin contact with formaldehyde may cause an allergic reaction in some people. Vision impairment and enlargement of liver may occur from methanol component. Formaldehyde is a suspected carcinogen.
Can cause severe abdominal pain, violent vomiting, headache, and diarrhea. Larger doses may produce decreased body temperature, pain in the digestive tract, shallow respiration, weak irregular pulse, unconsciousness and death.
May cause sore throat, coughing, and shortness of breath. Causes irritation and sensitization of the respiratory tract. Concentrations of 25 to 30 ppm cause severe respiratory tract injury leading to pulmonary edema and pneumonitis. May be fatal in high concentrations.
Toxic. May cause irritation to skin with redness, pain, and possibly burns. Skin absorption may occur with symptoms paralleling those from ingestion. Formaldehyde is a severe skin irritant and sensitizer. Contact causes white discoloration, smarting, cracking and scaling.
Vapors cause irritation to the eyes with redness, pain, and blurred vision. Higher concentrations or splashes may cause irreversible eye damage.
Ipecac induced vomiting is not recommended because of the potential for cardiovascular instability. Dilution: following ingestion and/or prior to gastric evacuation, immediately dilute with 4 to 8 ounces (120 to 240 ml) of milk or water (not to exceed 15 ml/kg in a child).
Move victim to fresh air. Apply artificial respiration if victim is not breathing. Administer oxygen if breathing is difficult.
Remove contaminated clothing and wash exposed area thoroughly with soap and water. A physician should examine the area if irritation or pain persists.
Medical facility: irrigate with sterile 0.9% Saline for at least an hour or until the cul-de-sacs are free of particulate matter and returned to neutrality (confirm with ph paper).