It could be that some hair salons order the concentrated form of H2O2 that is 35% and used in the food industry. The salons making their own diluted formulations with the 35% H2O2
Hydrogen Peroxide Grades
3% Hydrogen Peroxide (Drug/Grocery Store Variety)
Used as antimicrobial agent for treating wounds and sanitizing agent
[Made from 50% Super D Peroxide, Diluted. Contains stabilizers - phenol, acetanilide, sodium stanate, tetrasodium phosphate among them.]
[This peroxide contains known chemicals do not ingest!]
6% Hydrogen Peroxide
Used by Beauticians for Coloring Hair. Used as sanitizing agent.
Comes in strengths labeled 10,20,40 volume. Must have activator added to be used as a bleach.
[Contains stabilizers, additives, and impurities dependent on manufacturing and dilution process. Do not ingest.]
30% Re-Agent Hydrogen Peroxide
Used in medical research.
[Contains stabilizers, additives, and impurities dependent on manufacturing and dilution process. Do not ingest.]
30-32% Electronic Grade Hydrogen Peroxide
Used for washing transistors and integrated chip parts before assembly.
[Contains stabilizers, additives, and impurities dependent on manufacturing and dilution process. Do not ingest.]
35% Food Grade Hydrogen Peroxide (Also 50% Food Grade H2O2)
[....*....]. Also used to spray inside of foil lined containers for food storage - known as the aseptic packaging system. [...*...additional information removed for FDA compliance]
[Contains stabilizers, additives, and impurities dependent on manufacturing and dilution process.
—e.g. This Food Grade Hyrogen Peroxide is Stabilized using tin based formulations ]
35% Technical Grade Hydrogen Peroxide (Click to Order Now)
Used for waste water treatment and the disinfection of potable water, cosmetics, and laundry applications. [...*...additional information removed for FDA compliance] [May contain a small amount of phosphorus to neutralize any chlorine in the water it is combined with.]
MATERIAL SAFETY DATA SHEET & Technical Details: Hydrogen Peroxide (20 to 40%)
35% Standard Grade Hydrogen Peroxide (Also 50%, 60%, 70% Standard Grades)
Used mainly for bleaching in the pulp and paper industry and in the textile industry; oxidation reactions in the chemical industry; environmental processes (detoxification and deodorization). Used for Waste water treatment.
[Contains stabilizers, additives, and impurities Do not ingest.]
90% Hydrogen Peroxide
Used by the military as a source of Oxygen at Cape Canaveral. Used as a propulsion source in rocket fuel.
99.6% Hydrogen Peroxide
This was first made in 1954 as an experiment to see how pure a hydrogen peroxide could be manufactured.