Perfluorooctanesulfonic acid

January 28, 2019
I’m a bad actor that makes excellent foams.
What molecule am I?
Image of Perfluorooctanesulfonic acid 3D Image of Perfluorooctanesulfonic acid

Perfluorooctanesulfonic acid, usually abbreviated to PFOS, was once a widely used surfactant in fabric protectors, firefighting foams, and photolithographic chemical mixtures. It was introduced in 1949 by 3M Co. (then known as Minnesota Mining and Manufacturing Co.).

By 1968, traces of PFOS began to appear in human blood. 3M began to phase it out in 2000, but it and similar perfluorinated compounds continue to be produced in China.

Because of the multiple hazards imposed by PFOS and its cousins (see hazard information box), efforts have been made to develop lower fluorine content or fluorine-free foams for several years. Specifically, perfluorinated C6 surfactants have lower toxicological and environmental profiles than the C8s. Some of the C6s meet US military foam standards.

Thus far, the C6 products have significantly outperformed fluorine-free surfactants. But the pressure is on to develop better non-fluorine foams because last year Congress passed, and the president signed, an act that allows civilian airports to use these foams to fight fires.

Perfluorooctanesulfonic acid hazard information

GHS classification*: corrosive to metals, category 1
H290—May be corrosive to metals  Chemical Safety Warning
GHS classification: acute toxicity, oral, category 3
H301—Toxic if swallowedChemical Safety Warning
GHS classification: skin corrosion, category 1B
H314—Causes severe skin burns and eye damageChemical Safety Warning
GHS classification: serious eye damage, category 1
H318—Causes serious eye damageChemical Safety Warning
GHS classification: acute toxicity, inhalation, category 4
H332—Harmful if inhaledChemical Safety Warning
GHS classification: carcinogenicity, category 2
H351—Suspected of causing cancerChemical Safety Warning
GHS classification: reproductive toxicity, category 1A
H360—May damage fertility or the unborn childChemical Safety Warning
GHS classification: hazardous to the aquatic environment, acute hazard, category 2
H401—Toxic to aquatic life
GHS classification: hazardous to the aquatic environment, long-term hazard, category 2
H411—Toxic to aquatic life with long-lasting effectsChemical Safety Warning

*Globally Harmonized System of Classification and Labeling of Chemicals. Explanation of pictograms.

Perfluorooctanesulfonic acid fast facts

CAS Reg. No.1763-23-1
Empirical formulaC8HF17O3S
Molar mass500.13 g/mol
AppearanceWhite powder
Melting pointNot available
Boiling point258–260 ºC
Water solubility680 mg/L

MOTW update:
April 17, 2023

Cannabidiol1 (CBD) was the Molecule of the Week for February 6, 2017. It is a non-psychoactive marijuana constituent that is useful for controlling pain and other medical conditions. Perfluorooctanesulfonic acid2 (PFOS) was once a widely used surfactant; but because it became an environmental pollutant—even appearing in human blood—it was removed from the market.

What’s the connection between CBD and PFOS? Earlier this month, Hang Yin, Shu Li, and co-workers at Northeast Agricultural University (Harbin, China) reported that administering CBD can attenuate PFOS-induced heart injury. In a mouse study, the researchers found that CBD alleviates myocardial cell apoptosis caused by PFOS by restoring antioxidant capacity, mitochondrial function, and energy metabolic homeostasis to the cells.

1. CAS Reg. No. 13956-29-1.
2. CAS Reg. No. 1763-23-1.

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