Skip to content
CarCareTruth

Urea Monohydrochloride

  • Acids
  • CAS 506-89-8
  • IUPAC: Urea; hydrochloride

Urea Monohydrochloride (CAS 506-89-8) appears in 1 of the 2,122 car-care products CarCareTruth tracks (as of August 2026).

GHS-classified at mixture level: Met. Corr. 1 (H290), Acute Tox. 4 Oral (H302), Skin Irrit. 2 (H315), Eye Dam. 1 (H318). The HCl component is responsible for the corrosive and eye damage classifications. Not a Prop 65-listed substance.

Urea monohydrochloride (CAS 506-89-8) is the hydrochloride salt of urea — formed by combining urea (CO(NH₂)₂) with hydrochloric acid. It dissociates in aqueous solution to release hydrogen chloride (HCl) and urea. The result is a mildly complexed acid source that delivers controlled acidity without the fuming and corrosive aggressiveness of anhydrous HCl. At 5–10% concentration in water it produces solutions with pH < 2.

In detailing chemistry, urea hydrochloride is used as the active acid in products marketed as alternatives to "harsh acids" like hydrofluoric acid, phosphoric acid, and ammonium bifluoride. It dissolves calcium and magnesium mineral deposits (water spots, scale) through acid-base neutralization. The urea component may provide some buffering or surface-wetting properties but the primary mechanism is the HCl activity.

GHS classification at product mixture levels includes H290 (corrosive to metals), H302 (harmful if swallowed), H315 (skin irritation Cat 2), and H318 (serious eye damage Cat 1). These classifications reflect the corrosive acid chemistry at the concentrations used in commercial detailing formulas.

Health & environment profile

VOC
no
Prop 65 listed
no
Asthmagen
no
EPA Safer Choice
no
Aquatic toxicity
no
Biodegradable
no
Bioaccumulative
no
Persistent
no
Ozone depleting
no
Microplastic
no
PFAS
no
Env. score
3/5
Purpose: Controlled-release HCl acid source for mineral deposit removal; used in patented water spot remover formulas

Common questions about Urea Monohydrochloride

What is Urea Monohydrochloride used for in car care?
Controlled-release HCl acid source for mineral deposit removal; used in patented water spot remover formulas
Is Urea Monohydrochloride a VOC?
No. Urea Monohydrochloride is not classified as a volatile organic compound (VOC).
Is Urea Monohydrochloride on California's Proposition 65 list?
No. Urea Monohydrochloride is not on California's Proposition 65 list.

1 product 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.