Provenance

Reference data from EU CLP Annex VI and published regulations — verify against your supplier's SDS before use.

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Substance profile

Parathion

Parathion is the pure material is a yellowish liquid at temperatures above 6 °C with an usually has a faint odor.

CAS 56-38-2 C10H14NO5PS 291.26 g/mol Danger

01 · Identification

What Parathion is

Parathion is the pure material is a yellowish liquid at temperatures above 6 °C with an usually has a faint odor. Its molecular formula is C10H14NO5PS and its molecular weight is 291.26 g/mol. It boils at 375 °C, melts at 6.1 °C.

Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).

02 · Identifiers

Parathion identifiers and molecular data

Parathion CAS number and EC number

CAS number56-38-2
EC number200-271-7
Index number (CLP Annex VI)015-034-00-1

Parathion molecular formula and molecular weight

Molecular formulaC10H14NO5PS
Molecular weight291.26 g/mol
Chemical class Hazardous Air Pollutants (HAPs)

Other names for Parathion

  • parathion (ISO)
  • O,O-diethyl O-4-nitrophenyl phosphorothioate

03 · GHS classification

Parathion hazard classification

Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.

Parathion pictograms and signal word

Signal wordDanger

Parathion hazard class and category

GHS hazard classes Parathion falls into
Hazard class Category From code Pictogram
Acute toxicity - oral GHS chapter 3.1 Category 1 or 2 H300 GHS06
Acute toxicity - dermal GHS chapter 3.1 Category 3 H311 GHS06
Acute toxicity - inhalation GHS chapter 3.1 Category 1 or 2 H330 GHS06
Specific target organ toxicity - repeated exposure GHS chapter 3.9 Category 1 H372 GHS08
Hazardous to the aquatic environment - acute GHS chapter 4.1 Category 1 H400 GHS09
Hazardous to the aquatic environment - chronic GHS chapter 4.1 Category 1 H410 GHS09

Where two values are shown with “or”, the hazard statement is shared by more than one category or by more than one class, and the code alone does not say which. H272, for example, belongs to oxidising liquids and to oxidising solids — the physical state decides. The binding answer for a specific entry is in the CLP Annex VI table itself.

Parathion hazard statements (H-codes)

Hazard statements assigned to Parathion
CodeHazard statement
H330 Fatal if inhaled.
H300 Fatal if swallowed.
H311 Toxic in contact with skin.
H372 Causes damage to organs <or state all organs affected, if known> through prolonged or repeated exposure <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
H400 Very toxic to aquatic life.
H410 Very toxic to aquatic life with long lasting effects.

This page lists only the codes assigned to Parathion. The full reference lives on the hazard statements hub, the precautionary statements hub and the GHS pictograms hub.

Safety Data Sheet

Getting an SDS for Parathion

A Safety Data Sheet is written for a product, not for a substance: the supplier of the grade you actually buy issues it, so two suppliers of Parathion issue two different sheets. That is why there is no single authoritative SDS for a substance to download — what there is, is the job of collecting the sheets for the products you hold and keeping them current as suppliers revise them.

04 · Precautionary statements

Parathion precautionary statements

CLP Annex VI assigns 14 precautionary statements to Parathion. They are grouped the way a label groups them: what to do before handling, what to do when something has already happened, how to store it and how to dispose of it.

Disposal

What has to happen to the contents and the empty container.

Reading the notation. is a blank the supplier fills in — not a truncated sentence.· [square brackets] mark a part printed only when it applies.

05 · Names in the regulation

Parathion name in 23 EU languages

CLP Annex VI Part 3 is published in every language edition of the regulation, and the identification column is written out in each of them. Nothing below is translated by us: each line is the name as that edition prints it. Under Art. 18(2) the substance name from Annex VI is a lawful product identifier, so this is the wording to put on a label going to that market — and where the cell lists several designations, any one of them qualifies.

Language Name in CLP Annex VI Part 3
Bulgarian български паратион (ISO) O , O -диетилов О -4-нитрофенилов фосфоротиоат
Spanish español Paratión (ISO) fosforotioato de O , O -dietilo y O -4-nitrofenilo
Czech čeština parathion (ISO) O, O -diethyl- O -(4-nitrofenyl)-fosforothioát
Danish dansk parathion (ISO) O, O- diethyl- O- 4-nitrophenylthiophosphat
German Deutsch Parathion (ISO) O , O -Diethyl- O -4-nitrophenylphosphorothioat
Estonian eesti paratioon (ISO) O , O -dietüül- O -4-nitrofenüülfosforotioaat
Greek ελληνικά parathion (παραθείο) (ISO) θειοφωσφορικό O , O -διαιθύλιο O -4-νιτροφαινύλιο
English English parathion (ISO) O , O -diethyl O -4-nitrophenyl phosphorothioate
French français parathion (ISO) phosphorothioate de O , O -diéthyle et de O -4-nitrophényle
Croatian hrvatski paration (ISO) O , O -dietil- O -4-nitrofenil-fosforotioat
Italian italiano paration (ISO) tiofosfato di O, O-dietile e O-4-nitrofenile
Latvian latviešu parations (ISO) O , O -dietil- O -4-nitrofenilfosfortioāts
Lithuanian lietuvių parationas (ISO) O , O -dietil- O -4-nitrofeniltiofosfatas
Hungarian magyar paration (ISO) O , O -dietil O -4-nitrofenil-tiofoszfát
Maltese Malti paratjon (ISO) fosforotijoat ta’ O , O -dietil O -4-nitrofenil
Dutch Nederlands parathion (ISO) O , O -diëthyl- O -4-nitrofenylthiofosfaat
Polish polski paration (ISO) tiofosforan O , O -dietylu- O -4-nitrofenylu
Portuguese português paratião (ISO) tiofosfato de O , O -dietilo e de O -4-nitrofenilo
Romanian română paration (ISO) tiofosfat de O , O -dietil și de O -4-nitrofenil
Slovak slovenčina paratión (ISO) O, O -dietyl- O -(4-nitrofenyl)-fosforotioát
Slovenian slovenščina paration (ISO) O , O -dietil O -4-nitrofenil fosforotioat
Finnish suomi parationi (ISO) O , O -dietyyli- O -4-nitrofenyylifosforotioaatti
Swedish svenska paration (ISO) O , O -dietyl- O -4-nitrofenylfosfortioat

All 23 language editions of Annex VI carry this entry. Irish is the twenty-fourth official EU language and has no line here for a different reason: no consolidated CLP text has ever been published in Irish, so there is no Irish edition of Annex VI to quote a name from. Source: consolidated CLP, CELEX 02008R1272, language editions. © European Union, https://eur-lex.europa.eu — only the electronic Official Journal of the European Union is authentic.

06 · Label elements

Parathion GHS label elements

Everything CLP Annex VI fixes for Parathion, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.

GHS06 Skull and crossbones pictogramGHS08 Health hazard pictogramGHS09 Environment pictogram

Danger

Parathion

  • Fatal if inhaled.
  • Fatal if swallowed.
  • Toxic in contact with skin.
  • Causes damage to organs <or state all organs affected, if known> through prolonged or repeated exposure <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
  • Very toxic to aquatic life.
  • Very toxic to aquatic life with long lasting effects.
  • Do not breathe dust/fume/gas/mist/vapours/spray.
  • Do not eat, drink or smoke when using this product.
  • Use only outdoors or in a well-ventilated area.
  • Avoid release to the environment.
  • Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/
  • IF SWALLOWED:
  • IF ON SKIN:
  • IF INHALED:
  • Immediately call a POISON CENTER/doctor/
  • Get medical advice/attention if you feel unwell.
  • Rinse mouth.
  • Wash with plenty of water/
  • Collect spillage.
  • Dispose of contents/container to

Supplier name, address and telephone number· Product identifier·Nominal quantity

Need this as an actual label? Open Parathion in the GHS label constructor →

07 · Health hazards

Parathion health hazards and exposure limits

Parathion hazard summary

parathion is a yellow-to-brown liquid with an odor of garlic. It is often dissolved in a hydrocarbon solvent before use. Parathion itself is not volatile. It is almost insoluble in water, slightly soluble in petroleum oils, and miscible with many organic solvents.

Source: Agency for Toxic Substances and Disease Registry (ATSDR)

Parathion carcinogenicity classification

IARC classification Group 2B — Possibly carcinogenic to humans
IARC monographs Volume 30: (1983) Miscellaneous Pesticides; Volume 112: (2017) Some Organophosphate Insecticides and Herbicides

Studied by the US National Toxicology Program: TR-070: Bioassay of Parathion for Possible Carcinogenicity (CASRN 56-38-2) (1979 )

Classification of carcinogenicity: 1) evidence in humans: no adequate data; 2) evidence in animals: limited. Overall summary evaluation of carcinogenic risk to humans is Group 3: The agent is not classifiable as to its carcinogenicity to humans. /From table/

Source: Hazardous Substances Data Bank (HSDB)

Cancer Classification: Group C Possible Human Carcinogen

Source: Hazardous Substances Data Bank (HSDB)

An IARC group and a CLP classification answer different questions. IARC judges whether the evidence for cancer in humans is strong enough; CLP Annex VI is the legally binding EU classification. A substance can carry one and not the other.

Parathion occupational exposure limits

US occupational exposure limits reported for Parathion. PEL is enforceable (OSHA), REL is a recommendation (NIOSH), IDLH is the concentration at which escape becomes impossible without injury.
Limit Value Source
PEL 0.1 [mg/m3] Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
PEL 0.1 mg/m³ Occupational Safety and Health Administration (OSHA)
PEL TWA 0.1 mg/m3 [skin] The National Institute for Occupational Safety and Health (NIOSH)
REL 0.05 mg/m³ Occupational Safety and Health Administration (OSHA)
REL TWA 0.05 mg/m3 [skin] The National Institute for Occupational Safety and Health (NIOSH)
IDLH 10 mg/m3 (NIOSH, 2024) CAMEO Chemicals
IDLH 10.0 [mg/m3] Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
IDLH 10 mg/cu m Hazardous Substances Data Bank (HSDB)

These are United States values. The European Union sets its own indicative and binding limits, and the figure that applies at a given workplace is the one in the local regulation — not the one shown here.

08 · Physical and chemical properties

Parathion properties

Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.

Parathion boiling point

Property Value Conditions Source
Boiling point 375 °C (707 °F) at 760 mmHg HSDB
375 °C (707 °F) NIOSH

Parathion melting point

Property Value Conditions Source
Melting point 6.1 °C (43 °F) HSDB
6.11 °C (43 °F) NIOSH

Parathion density

Property Value Conditions Source
Density 1.27 g/cm³ NIOSH
1.26 g/cm³ CAMEO
1.26 g/cm³ at 25 °C HSDB

Parathion solubility

Property Value Conditions Source
Solubility PRACTICALLY INSOL IN PETROLEUM ETHER, KEROSENE, & USUAL SPRAY OILS HSDB
COMPLETELY SOL IN ALCOHOLS, ESTERS, ETHERS, KETONES, AROMATIC HYDROCARBONS, ANIMAL & VEGETABLE OILS HSDB
SOL IN CHLOROFORM HSDB

Parathion vapor pressure

Property Value Conditions Source
Vapor pressure 0.00004 mmHg NIOSH
0.00000668 mmHg at 20 °C HSDB
0.0000378 mmHg at 20 °C CAMEO

Parathion flash point

Property Value Conditions Source
Flash point 200 °C (392 °F) NIOSH
120 °C (248 °F) ICSC
140 °C (284 °F) range, midpoint shown HSDB

Parathion lower explosive limit (LEL)

Property Value Conditions Source
Lower explosive limit (LEL) CONTAINERS MAY EXPLODE WHEN HEATED. HSDB
Class IIIB Combustible Liquid: Fl.P. at or above 200 °F. NIOSH
When a sample was heated in a small test tube it decomposed & in a few minutes the residue exploded. decomposes HSDB

Parathion upper explosive limit (UEL)

Property Value Conditions Source
Upper explosive limit (UEL) Not highly flammable. (EPA, 1998) CAMEO

Parathion odor threshold

Property Value Conditions Source
Odor threshold 4.00X10-2 ppm (detection in water; purity not specified) HSDB
0.470 mg/cu m HSDB
Odor Threshold: 0.476 mg/m (low); 0.4760 mg/m (high). HSDB

Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.

09 · Fire and explosion

Parathion fire and explosion behaviour

These are descriptions rather than measured values, so they are kept out of the table above and quoted here with the source that reported them.

Parathion fire potential

... NOT HIGHLY FLAMMABLE

Source: Hazardous Substances Data Bank (HSDB)

10 · Handling and storage

Parathion storage and handling

Parathion safe storage

Provision to contain effluent from fire extinguishing. Separated from strong oxidants and food and feedstuffs. Well closed. Keep in a well-ventilated room.

Source: ILO-WHO International Chemical Safety Cards (ICSCs)

Parathion storage conditions

All parathion containers shall be protected from ... corrosion, mechanical damage, and sources of ignition. ... Outdoor storage facilities shall be located at least 20 feet from any dwellings, or a populated area and shall be equipped with a sprinkler system, where feasible.

Source: Hazardous Substances Data Bank (HSDB)

Parathion incompatible materials

Strong oxidizers, alkaline materials.

Source: Hazardous Substances Data Bank (HSDB)

Parathion reactivity

Light-yellow liquid, it turns solid at 6 °C, a deadly poison by all routes. Organic phosphate insecticide, acts as an inhibitor of cholinesterase. Violent reaction when used as solvent to dissolve endrin. When heated to decomposition it emits very toxic fumes of oxides of sulfur, phosphorus, and nitrogen [Lewis, 3rd ed., 1993, p. 984].

Source: CAMEO Chemicals

Planning storage for a mix of chemicals? Check Parathion in the storage compatibility matrix →

11 · Questions

Parathion — frequently asked questions

What is the CAS number of Parathion?

The CAS number of Parathion is 56-38-2. Its EC number is 200-271-7.

What is the chemical formula of Parathion?

The molecular formula of Parathion is C10H14NO5PS and its molecular weight is 291.26 g/mol.

What does a Parathion label have to show?

Under CLP Annex VI the label for Parathion carries the pictograms Skull and crossbones, Health hazard and Environment and the signal word is Danger.

Is Parathion flammable?

CLP Annex VI assigns Parathion no flammability hazard class. That is not a statement that it cannot burn: the harmonised list only records the hazards that were assessed for it. The flash point reported for it is 200 °C (392 °F) (NIOSH).

Is Parathion a carcinogen?

CLP Annex VI records no harmonised carcinogenicity classification for Parathion. Annex VI is a list of agreed classifications, not a list of substances found safe, so this is an absence of a classification rather than a clean bill of health. IARC places it in Group 2B: possibly carcinogenic to humans.

What is the exposure limit for Parathion?

The US occupational exposure limit reported for Parathion is 0.1 [mg/m3] (Haz-Map, Information on Hazardous Chemicals and Occupational Diseases). Limits differ by country: the EU sets its own indicative and binding values, and the figure that applies at a given workplace is the one in the local regulation.

What is the boiling point of Parathion?

The boiling point reported for Parathion is 375 °C (707 °F), at 760 mmHg (HSDB).

What is the melting point of Parathion?

The melting point reported for Parathion is 6.1 °C (43 °F) (HSDB).

How should Parathion be stored?

All parathion containers shall be protected from ... corrosion, mechanical damage, and sources of ignition. ... Outdoor storage facilities shall be located at least 20 feet from any dwellings, or a populated area and shall be equipped with a sprinkler system, where feasible. (Hazardous Substances Data Bank (HSDB))

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