Chemical data sheets provided by many countries contain codes indicating certain "hazard information", such as R23, R45, etc. These hazard information codes have the following meanings:

R1: Explosive when dry;

R2: There is a risk of explosion due to impact, friction, fire or other ignition sources;

R3: There is an extremely high risk of explosion due to impact, friction, fire or other ignition sources;

R4: Generates extremely sensitive explosive metal compounds;

R5: Heating may cause explosion;

R6: Explodes with or without contact with air;

R7: May cause fire;

R8: Contact with combustible materials may cause fire;

R9: Explodes when mixed with flammable materials;

R10: Flammable;

R11: Highly flammable;

R12: Extremely flammable;

R13: Extremely flammable liquefied gas.

R14: Reacts violently with water;

R15: Releases highly flammable gases on contact with water;

R16: Explosive when mixed with oxidizing substances;

R17: prone to spontaneous combustion in air;

R18: May generate flammable and explosive vapor-air mixtures during use.

R19: May generate explosive peroxide substances.

R20: Harmful if inhaled.

R21: Harmful in contact with skin.

R22: Harmful if swallowed.

R23: Toxic if inhaled.

R24: Toxic in contact with skin.

R25: Toxic if swallowed.

R26: Extremely toxic if inhaled.

R27: Extremely toxic in contact with skin.

R28: Extremely toxic if swallowed.

R29: Releases toxic gases when in contact with water.

R30: May convert to highly flammable substances when used.

R31: Releases toxic gases on contact with acids.

R32: Releases highly toxic gases on contact with acids.

R33: Risk of cumulative effects.

R34: May cause burns.

R35: Causes severe burns.

R36: Irritation to eyes.

R37: Irritates the respiratory system;

R38: Irritating to skin.

R39: There is a very serious risk of irreversible effects.

R40: There may be a risk of irreversible effects;

R41: Risk of serious damage to eyes.

R42: May cause allergic reaction if inhaled.

R43: May cause allergic reaction in contact with skin.

R44: Danger of explosion if heated under seal.

R45: May cause cancer.

R46: May cause irreversible genetic damage

R47: May cause reproductive defects.

R48: Risk of serious damage to health through prolonged exposure.

R49: Causes cancer if inhaled.

R50: Extremely toxic to aquatic life;

R51: Toxic to aquatic life.

R52: Harmful to aquatic life.

R53: Has long-term harmful effects on the aquatic environment.

R54: Toxic to plants.

R55: Toxic to animals.

R56: Toxic to soil organisms.

R57: Toxic to bees.

R58: May cause long-term harmful effects on the environment.

R59: Harmful to the ozone layer.

R60: May reduce reproductive potential.

R61: May cause harm to an unborn baby.

R62: Risk of impairing reproductive potential.

R63: May harm the unborn baby.

R64: May cause harm to nursing infants;

R65: May cause damage to lung organs if swallowed.

R66: Repeated exposure may cause dryness or cracking of skin.

R67: Vapors may cause drowsiness and fainting.

R68: There is a risk of irreversible effects.

R20/21: Harmful by inhalation and in contact with skin.

R20/21/22: Harmful by inhalation, skin contact and if swallowed.

R20/22: Harmful if inhaled and if swallowed.

R21/22: Harmful in contact with skin and if swallowed.

R23/24/25: Toxic by inhalation, skin contact and if swallowed.

R23/25: Toxic if inhaled and if swallowed.

R26/27/28: Very toxic if inhaled, in contact with skin and if swallowed;

R26/28: Very toxic if inhaled and if swallowed.

R36/37: Irritating to eyes and respiratory tract.

R36/37/38: Irritating to eyes, respiratory tract and skin.

R14/15: Reacts violently with water, releasing extremely flammable gas;

R15/29: Releases toxic, highly flammable gases on contact with water;

R23/24: Toxic by inhalation and in contact with skin;

R24/25: Toxic in contact with skin and if swallowed;

R26/27: Very toxic by inhalation and in contact with skin;

R27/28: Very toxic in contact with skin and if swallowed;

R36/38: Irritating to eyes and skin;

R37/38: Irritating to respiratory system and skin;

R39/23: Toxic: Danger of extremely serious and irreversible effects if inhaled;

R39/23/24: Toxic: Danger of extremely serious and irreversible effects by inhalation and contact with skin;

R39/23/24/25: Toxic: Danger of extremely serious and irreversible effects by inhalation, contact with skin and swallowing;

R39/23/25: Toxic: Danger of extremely serious and irreversible effects if inhaled and swallowed;

R39/24: Toxic: Danger of extremely serious and irreversible effects in contact with skin;

R39/24/25: Toxic: Danger of very serious and irreversible effects in contact with skin and if swallowed;

R39/25: Toxic: Danger of extremely serious and irreversible effects if swallowed;

R39/26: Extremely high toxicity: Danger of extremely serious irreversible effects if inhaled;

R39/26/27: Extremely high toxicity: Danger of extremely serious irreversible effects through inhalation and contact with skin;

R39/26/27/28: Extremely toxic: Danger of extremely serious irreversible effects through inhalation, skin contact and swallowing;

R39/26/28: Extremely toxic: Danger of extremely serious irreversible effects if inhaled and swallowed;

R39/27: Extremely toxic: Danger of extremely serious irreversible effects in contact with skin;

R39/27/28: Extremely toxic: Danger of extremely serious irreversible effects in contact with skin and ingestion;

R39/28: Extremely toxic: Danger of extremely serious and irreversible effects if swallowed;

R40/20: Harmful: Risk of irreversible effects if inhaled;

R40/20/21: Harmful: Risk of irreversible effects by inhalation and contact with skin;

R40/20/21/22: Harmful: Risk of irreversible effects if inhaled, in contact with skin and swallowed;

R40/20/22: Harmful: Risk of irreversible effects if inhaled and swallowed;

R40/21: Harmful: Risk of irreversible effects in contact with skin;

R40/21/22: Harmful: Risk of irreversible effects in contact with skin and if swallowed;

R40/22: Harmful: Risk of irreversible effects if swallowed;

R42/43: May cause sensitization by inhalation and skin contact;

R48/20: Harmful: Risk of serious damage to health through long-term exposure through inhalation;

R48/20/21: Hazardous: Risk of serious damage to health through inhalation and prolonged contact with skin;

R48/20/21/22: Harmful: Risk of serious damage to health through long-term exposure through inhalation, skin and swallowing;

R48/20/22: Hazardous: Risk of serious damage to health through long-term exposure through inhalation and swallowing;

R48/21: Harmful: Risk of serious damage to health through long-term skin contact;

R48/21/22: Hazardous: Risk of serious damage to health through prolonged exposure through skin and ingestion;

R48/22: Harmful: Risk of serious damage to health if swallowed and long-term exposure;

R48/23: Toxic: Risk of serious damage to health through long-term exposure through inhalation;

R48/23/24: Toxic: Risk of serious damage to health through inhalation and prolonged contact with skin;

R48/23/24/25: Toxic: Risk of serious damage to health through long-term exposure through inhalation, skin and ingestion;

R48/23/25: Toxic: Risk of serious damage to health through long-term exposure through inhalation and swallowing;

R48/24: Toxic: Risk of serious damage to health through long-term skin contact;

R48/24/25: Toxic: Risk of serious damage to health through prolonged exposure through skin and ingestion;

R48/25: Toxic: Risk of serious damage to health if swallowed and long-term exposure;

R50/53: Extremely toxic to aquatic life and may cause long-term adverse effects in the aquatic environment;

R51/53: Toxic to aquatic life, may cause long-term adverse effects in the aquatic environment;

R52/53: Harmful to aquatic life and may cause long-term adverse effects in the aquatic environment