Historic Preservation - Technical Procedures
Removing Blood Stains From Concrete
Hstrc Concrete: Investigation & Rpr/Pre-Conf Training - 1989
Removing Blood Stains From Concrete
REMOVING BLOOD STAINS FROM CONCRETE
THE CLEANING OR REMOVAL OF STAINS FROM CONCRETE MAY INVOLVE THE
USE OF LIQUIDS, DETERGENTS OR SOLVENTS WHICH MAY RUN OFF ON
ADJACENT MATERIAL, DISCOLOR THE CONCRETE OR DRIVE THE STAINS DEEPER
INTO POROUS CONCRETE. USE THE PRODUCTS AND TECHNIQUES DESCRIBED
HERE ONLY FOR THE COMBINATIONS OF DIRT/STAIN AND CONCRETE SPECIFIED.
A. This procedure includes guidance on removing blood stains
from concrete using sodium peroxide and water.
B. Safety Precautions:
1. DO NOT save unused portions of stain-removal
2. DO NOT store any chemicals in unmarked containers.
3. EXCELLENT VENTILATION MUST BE PROVIDED WHEREVER ANY
SOLVENT IS USED. USE RESPIRATORS WITH SOLVENT
4. No use of organic solvents indoors should be
allowed without substantial air movement. Use only
spark-proof fans near operations involving
5. Provide adequate clothing and protective gear where
the chemicals are indicated to be dangerous.
6. Have available antidote and accident treatment
chemicals where noted.
C. See 01100-07-S for general project guidelines to be
reviewed along with this procedure. These guidelines
cover the following sections:
1. Safety Precautions
2. Historic Structures Precautions
4. Quality Assurance
5. Delivery, Storage and Handling
6. Project/Site Conditions
7. Sequencing and Scheduling
8. General Protection (Surface and Surrounding)
These guidelines should be reviewed prior to performing
this procedure and should be followed, when applicable,
along with recommendations from the Regional Historic
Preservation Officer (RHPO).
NOTE: Chemical products are sometimes sold under a common
name. This usually means that the substance is not as pure as
the same chemical sold under its chemical name. The grade of
purity of common name substances, however, is usually adequate
for stain removal work, and these products should be purchased
when available, as they tend to be less expensive. Common
names are indicated below by an asterisk (*).
A. Sodium Peroxide:
1. Other chemical or common names include Sodium
dioxide; Sodium binoxide*.
2. Potential Hazards: TOXIC (DO NOT BREATHE THE
DUST); CORROSIVE TO FLESH; FLAMMABLE (EXPLOSIVE IN
WATER, ACID OR ORGANIC SOLVENTS).
3. Available from chemical supply house, drugstore or
pharmaceutical supply distributor, hardware store,
paint store, or water and sanitation supply
distributor (often sold under a manufacturer's
brand name; the chemical name may appear on the
1. Other chemical or common names include Tribasic
sodium phosphate; Trisodium orthophosphate;
Trisodium phosphate; TSP*; Phosphate of soda*.
2. Potential Hazards: CORROSIVE TO FLESH.
3. Available from chemical supply distributor,
supermarket, grocery, or hardware store.
Sodium Thiosulfate - white sal or "hypo" of photographic
fixing agent (NA2S2O3):
1. A hygroscopic crystalline salt used especially as a
photographic fixing agent and a reducing or
2. Other chemical or common names include Sodium
hydrosulfite; Sodium Hyposulfite; Sodium
subsulfite; Antichlor*; Hypo*; Hyposulfite of
3. Potential Hazards: TOXIC; CORROSIVE TO CONCRETE,
STEEL, WOOD OR GLASS.
4. Available from chemical supply house, dry cleaning
supply distributor, drugstore or pharmaceutical
supply distributor, photographic supply distributor
(not camera shop), or water and sanitation supply
Hydrogen Peroxide (H202):
1. An unstable compound used especially as an
oxidizing and bleaching agent, an antiseptic, and a
2. Other chemical or common names include Peroxide of
hydrogen*; Solution of hydrogen dioxide*;
Superoxol*; (hydrogen peroxide is commonly sold as
a 3% solution; Superoxol is a 30% solution;
Superoxol causes flesh burns; 3% hydrogen peroxide
3. Potential Hazards: TOXIC (when concentrated);
CORROSIVE TO FLESH (gasoline, kerosene and mineral
spirits are each a mixture of compounds from
petroleum, all of which fall within a specified
range of properties); FLAMMABLE (in high
4. Available from chemical supply house, drugstore,
pharmaceutical supply distributor, or hardware
B. Acetic Acid:
1. A colorless pungent liquid acid that is the chief
acid of vinegar and that is used especially in
synthesis (as of plastics).
2. Other chemical or common names include Vinegar
acid*. (Vinegar itself, which contains about 4%
acetic acid, may be suitable for some purposes
requiring acetic acid.)
3. Potential hazards: CORROSIVE TO FLESH AND
CORROSIVE TO CONCRETE, STEEL, WOOD OR GLASS.
4. Available from chemical supply house (both
commercial and scientific), drugstore or
pharmaceutical supply distributor, grocery store or
supermarket, or hardware store.
1. Potential Hazards: CORROSIVE TO CONCRETE, STEEL,
WOOD OR GLASS.
2. Available from grocery store or supermarket.
3. Vinegar itself, which contains about 4% acetic
acid, may be suitable for some purposes requiring
D. Bandaging Materials
E. Clean, potable water
A. Cloth mask
B. Stiff bristle brushes (non-metallic)
1. Provide adequate wash solutions (i.e. water, soap
and towels) before starting the job.
2. Whenever acid is used, the surface should be
thoroughly rinsed with water as soon as its action
has been adequate. Otherwise it will continue
etching the concrete even though the stain is gone.
3.02 ERECTION, INSTALLATION, APPLICATION
NOTE: DO NOT TRY MORE THAN ONE TREATMENT ON A GIVEN AREA
UNLESS THE CHEMICALS USED FROM PRIOR TREATMENT HAVE BEEN
A. Saturate the surface with clear cold water.
B. Carefully sprinkle sodium peroxide powder over the
surface in a thin layer.
CAUTION: SODIUM PEROXIDE DUST IS HIGHLY TOXIC. WEAR A
CLOTH MASK OVER THE NOSE AND AVOID BREATHING THE SODIUM
PEROXIDE DUST. ALSO KEEP ALL AREAS OF THE SKIN PROTECTED
FROM THE DUST.
1. Solids of sodium orthophosphate, sodium thiosulfate
or a liquid 3% solution of hydrogen peroxide may be
used instead of sodium peroxide.
NOTE: SODIUM THIOSULFATE SHOULD NOT BE USED IN
CONFINED AREAS BECAUSE IT GENERATES ACRID FUMES OF
C. Sprinkle the surface with a fine mist of water or apply
a water-saturated bandage and allow to sit for a few
D. Thoroughly rinse the surface with clean, clear water,
scrubbing vigorously with a stiff bristle brush.
E. Neutralize any remaining alkali on the surface (not
necessary if hydrogen peroxide is used):
1. Brush the surface with vinegar.
2. Rinse with clean, clear water and allow to dry.
If alkali still remains,
1. Mix a solution of 1 part glacial acetic acid and 19
2. Brush the solution over the surface.
3. Thoroughly rinse the surface with clean, clear
water and allow to dry.
END OF SECTION