R-Phrases

R-phrases (short for Risk Phrases) are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous substances and preparations. The list was consolidated and republished in Directive 2001/59/EC, where translations into other EU languages may be found.
These risk phrases are used internationally not just in Europe and there is an ongoing effort towards complete international harmonization. (Note: missing R-number combinations indicate phrases that were deleted or replaced by another phrase.)

Risk Phrases

• R1: Explosive when dry
• R2: Risk of explosion by shock, friction, fire or other sources of ignition
• R3: Extreme risk of explosion by shock, friction, fire or other sources of ignition
• R4: Forms very sensitive explosive metallic compounds
• R5: Heating may cause an explosion
• R6: Explosive with or without contact with air
• R7: May cause fire
• R8: Contact with combustible material may cause fire
• R9: Explosive when mixed with combustible material
• R10: Flammable
• R11: Highly flammable
• R12: Extremely flammable
• R14: Reacts violently with water
• R15: Contact with water liberates extremely flammable gases
• R16: Explosive when mixed with oxidising substances
• R17: Spontaneously flammable in air
• R18: In use, may form flammable/explosive vapour-air mixture
• R19: May form explosive peroxides
• R20: Harmful by inhalation
• R21: Harmful in contact with skin
• R22: Harmful if swallowed
• R23: Toxic by inhalation
• R24: Toxic in contact with skin
• R25: Toxic if swallowed
• R26: Very toxic by inhalation
• R27: Very toxic in contact with skin
• R28: Very toxic if swallowed
• R29: Contact with water liberates toxic gas.
• R30: Can become highly flammable in use
• R31: Contact with acids liberates toxic gas
• R32: Contact with acids liberates very toxic gas
• R33: Danger of cumulative effects
• R34: Causes burns
• R35: Causes severe burns
• R36: Irritating to eyes
• R37: Irritating to respiratory system
• R38: Irritating to skin
• R39: Danger of very serious irreversible effects
• R40: Limited evidence of a carcinogenic effect
• R41: Risk of serious damage to eyes
• R42: May cause sensitisation by inhalation
• R43: May cause sensitisation by skin contact
• R44: Risk of explosion if heated under confinement
• R45: May cause cancer
• R46: May cause heritable genetic damage
• R48: Danger of serious damage to health by prolonged exposure
• R49: May cause cancer by inhalation
• R50: Very toxic to aquatic organisms
• R51: Toxic to aquatic organisms
• R52: Harmful to aquatic organisms
• R53: May cause long-term adverse effects in the aquatic environment
• R54: Toxic to flora
• R55: Toxic to fauna
• R56: Toxic to soil organisms
• R57: Toxic to bees
• R58: May cause long-term adverse effects in the environment
• R59: Dangerous for the ozone layer
• R60: May impair fertility
• R61: May cause harm to the unborn child
• R62: Possible risk of impaired fertility
• R63: Possible risk of harm to the unborn child
• R64: May cause harm to breast-fed babies
• R65: Harmful: may cause lung damage if swallowed
• R66: Repeated exposure may cause skin dryness or cracking
• R67: Vapours may cause drowsiness and dizziness
• R68: Possible risk of irreversible effects

Combinations

• R14/15: Reacts violently with water, liberating extremely flammable gases
• R15/29: Contact with water liberates toxic, extremely flammable gases
• R20/21: Harmful by inhalation and in contact with skin
• R20/22: Harmful by inhalation and if swallowed
• R20/21/22: Harmful by inhalation, in contact with skin and if swallowed
• R21/22: Harmful in contact with skin and if swallowed
• R23/24: Toxic by inhalation and in contact with skin
• R23/25: Toxic by inhalation and if swallowed
• R23/24/25: Toxic by inhalation, in contact with skin and if swallowed
• R24/25: Toxic in contact with skin and if swallowed
• R26/27: Very toxic by inhalation and in contact with skin
• R26/28: Very toxic by inhalation and if swallowed
• R26/27/28: Very toxic by inhalation, in contact with skin and if swallowed
• R27/28: Very toxic in contact with skin and if swallowed
• R36/37: Irritating to eyes and respiratory system
• R36/38: Irritating to eyes and skin
• R36/37/38: Irritating to eyes, respiratory system and skin
• R37/38: Irritating to respiratory system and skin
• R39/23: Toxic: danger of very serious irreversible effects through inhalation
• R39/24: Toxic: danger of very serious irreversible effects in contact with skin
• R39/25: Toxic: danger of very serious irreversible effects if swallowed
• R39/23/24: Toxic: danger of very serious irreversible effects through inhalation and in contact with skin
• R39/23/25: Toxic: danger of very serious irreversible effects through inhalation and if swallowed
• R39/24/25: Toxic: danger of very serious irreversible effects in contact with skin and if swallowed
• R39/23/24/25: Toxic: danger of very serious irreversible effects through inhalation, in contact with skin and if swallowed
• R39/26: Very Toxic: danger of very serious irreversible effects through inhalation
• R39/27: Very Toxic: danger of very serious irreversible effects in contact with skin
• R39/28: Very Toxic: danger of very serious irreversible effects if swallowed
• R39/26/27: Very Toxic: danger of very serious irreversible effects through inhalation and in contact with skin
• R39/26/28: Very Toxic: danger of very serious irreversible effects through inhalation and if swallowed
• R39/27/28: Very Toxic: danger of very serious irreversible effects in contact with skin and if swallowed
• R39/26/27/28: Very Toxic: danger of very serious irreversible effects through inhalation, in contact with skin and if swallowed
• R42/43: May cause sensitization by inhalation and skin contact
• R48/20: Harmful: danger of serious damage to health by prolonged exposure through inhalation
• R48/21: Harmful: danger of serious damage to health by prolonged exposure in contact with skin
• R48/22: Harmful: danger of serious damage to health by prolonged exposure if swallowed
• R48/20/21: Harmful: danger of serious damage to health by prolonged exposure through inhalation and in contact with skin
• R48/20/22: Harmful: danger of serious damage to health by prolonged exposure through inhalation and if swallowed
• R48/21/22: Harmful: danger of serious damage to health by prolonged exposure in contact with skin and if swallowed
• R48/20/21/22: Harmful: danger of serious damage to health by prolonged exposure through inhalation, in contact with skin and if swallowed
• R48/23: Toxic: danger of serious damage to health by prolonged exposure through inhalation
• R48/24: Toxic: danger of serious damage to health by prolonged exposure in contact with skin
• R48/25: Toxic: danger of serious damage to health by prolonged exposure if swallowed
• R48/23/24: Toxic: danger of serious damage to health by prolonged exposure through inhalation and in contact with skin
• R48/23/25: Toxic: danger of serious damage to health by prolonged exposure through inhalation and if swallowed
• R48/24/25: Toxic: danger of serious damage to health by prolonged exposure in contact with skin and if swallowed
• R48/23/24/25: Toxic: danger of serious damage to health by prolonged exposure through inhalation, in contact with skin and if swallowed
• R50/53: Very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment
• R51/53: Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment
• R52/53: Harmful to aquatic organisms, may cause long-term adverse effects in the aquatic environment
• R68/20: Harmful: possible risk of irreversible effects through inhalation
• R68/21: Harmful: possible risk of irreversible effects in contact with skin
• R68/22: Harmful: possible risk of irreversible effects if swallowed
• R68/20/21: Harmful: possible risk of irreversible effects through inhalation and in contact with skin
• R68/20/22: Harmful: possible risk of irreversible effects through inhalation and if swallowed
• R68/21/22: Harmful: possible risk of irreversible effects in contact with skin and if swallowed
• R68/20/21/22: Harmful: possible risk of irreversible effects through inhalation, in contact with skin and if swallowed

R-Phrases no longer in use

• R13: Extremely flammable liquefied gas.
• R47: May cause birth defects.