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Trisodium Phosphate

  • Bases
  • CAS 7601-54-9
  • IUPAC: trisodium phosphate

Trisodium Phosphate (CAS 7601-54-9) appears in 2 of the 1,812 car-care products CarCareTruth tracks (as of June 2026). It is readily biodegradable.

At concentrate strength, TSP is corrosive (H314) and causes severe skin burns and eye damage. At typical in-product concentrations of 1–5%, the mixture-level hazard depends on overall pH — in alkaline formulas containing NaOH and metasilicate, TSP contributes to the DANGER/H314 classification rather than independently determining it. Not on California Prop 65 list.

Trisodium phosphate (TSP) is an inorganic base used as a heavy-duty cleaning agent and pH buffer. In alkaline tire cleaners and degreasers, TSP boosts cleaning action by saponifying fatty soils and oil-based dressing residues at concentrations of 1–5%.

TSP is the traditional household pre-paint cleaner and is still used in automotive degreasers for its strong soil-removal efficacy. In strongly alkaline formulas containing sodium hydroxide and metasilicates, TSP's contribution to pH and corrosivity is additive — it is not the primary corrosivity driver but amplifies the overall alkaline hazard.

Environmental concern centers on phosphate's role in eutrophication: excessive phosphorus in waterways drives algal blooms that deplete dissolved oxygen. Consumer products with TSP typically discharge to municipal wastewater treatment systems that strip phosphorus before discharge to surface water. Storm-drain-destined vehicle applications (tire cleaners rinsed to pavement) have a more direct pathway. TSP is not classified as acutely aquatically toxic under GHS.

Health & environment profile

VOC
no
Prop 65 listed
no
Asthmagen
no
EPA Safer Choice
no
Aquatic toxicity
no
Biodegradable
yes
Bioaccumulative
no
Persistent
no
Ozone depleting
no
Microplastic
no
PFAS
no
Env. score
3/5
Purpose: Alkaline builder and cleaning agent in heavy-duty degreasers; raises pH for saponification of greases and oils

Common questions about Trisodium Phosphate

What is Trisodium Phosphate used for in car care?
Alkaline builder and cleaning agent in heavy-duty degreasers; raises pH for saponification of greases and oils
Is Trisodium Phosphate a VOC?
No. Trisodium Phosphate is not classified as a volatile organic compound (VOC).
Is Trisodium Phosphate on California's Proposition 65 list?
No. Trisodium Phosphate is not on California's Proposition 65 list.
Is Trisodium Phosphate biodegradable?
Yes. Trisodium Phosphate has a confirmed biodegradable profile.

2 products contain this

Related

Health and environment notes translate the manufacturer Safety Data Sheet, the GHS classification, and authoritative regulatory listings (California Prop 65, EPA). Not medical advice. They describe the ingredient itself; whether a hazard applies to a finished product depends on its concentration and how it's used.