Potassium Dichromate
Edouard Bastarache
IDENTIFICATION:
CAS No.: 7778-50-9
Chemical formula: K2Cr2O7
Molecular weight: 294.18
MAIN SYNONYMS:
French names:
Bichromate de potassium
Dichromate de potassium
English names:
Dichromic acid
Dipotassium salt
Potassium bichromate
Dipotassium dichromate
USES AND SOURCES OF EMISSION:
Manufacture of paints, inks and in ceramics.
HYGIENE AND SAFETY:
I. Physical and Chemical Properties:
Appearance: Orange-red crystals or powder
Odor: Odorless.
Solubility: 6.5% @ 10C (50F) in water.
Specific gravity: 2.676 @ 25C/4C
pH: 4.04 (1% aq. solution) 3.57 (10% aq. solution)
% Volatiles by volume @ 21C (70F): 0
Boiling point: 500C (932F)
Melting point: 398C (748F)
II. Fire Fighting Measures:
A. Fire:
Not combustible, but substance is a strong oxidizer and its heat
of reaction with reducing agents or combustibles may cause ignition.
Releases oxygen, upon decomposition, which enhances combustion.
B. Explosion:
Contact with oxidizable substances may cause extremely violent
combustion.
C. Fire extinguishing media:
Flood with large amounts of water. Water spray may be used to
keep fire exposed containers cool. Do not allow water runoff to
enter sewers or waterways.
D. Special information:
In the event of a fire, wear full protective clothing and NIOSH-approved
self-contained breathing apparatus with full facepiece operated
in the pressure demand or other positive pressure mode.
PREVENTION:
I. Stability and Reactivity:
A. Stability:
Stable under ordinary conditions of use and storage.
B. Hazardous decomposition products:
Burning may produce chrome oxides.
C. Hazardous polymerization:
Will not occur.
D. Incompatibilities:
Reducing agents, acetone plus sulfuric acid, boron plus silicon,
ethylene glycol, iron, hydrazine, and hydroxylamine. Any combustible,
organic or other readily oxidizable material (paper, wood, sulfur,
aluminum or plastics).
E. Conditions to avoid:
Heat, incompatibles.
II. Handling and Storage:
Protect against physical damage. Store in a dry location separate
from combustible, organic or other readily oxidizable materials.
Avoid storage on wood floors. Remove and dispose of any spilled
dichromates; do not return to original containers. Wear special
protective equipment for maintenance break-in or where exposures
may exceed established exposure levels. Wash hands, face, forearms
and neck when exiting restricted areas. Shower, dispose of outer
clothing, change to clean garments at the end of the day. Avoid
cross-contamination of street clothes. Wash hands before eating
and do not eat, drink, or smoke in workplace. Containers of this
material may be hazardous when empty since they retain product
residues (dust, solids); observe all warnings and precautions
listed for the product.
III. Accidental Release Measures:
Ventilate area of leak or spill. Wear appropriate personal protective
equipment.
Spills: Sweep up and containerize for reclamation or disposal.
Vacuuming or wet sweeping may be used to avoid dust dispersal.
IV. Exposure Controls/Personal Protection:
A. Ventilation System:
A system of local and/or general exhaust is recommended to keep
employee exposures below the Airborne Exposure Limits. Local exhaust
ventilation is generally preferred because it can control the
emissions of the contaminant at its source, preventing dispersion
of it into the general work area.
If the exposure limit is exceeded and engineering controls are
not feasible, a half facepiece particulate respirator (NIOSH type
N95 or better filters) may be worn for up to ten times the exposure
limit or the maximum use concentration specified by the appropriate
regulatory agency or respirator supplier, whichever is lowest.
A full-face piece particulate respirator (NIOSH type N100 filters)
may be worn up to 50 times the exposure limit, or the maximum
use concentration specified by the appropriate regulatory agency,
or respirator supplier, whichever is lowest.
If oil particles (e.g. lubricants, cutting fluids, glycerine,
etc.) are present, use a NIOSH type R or P filter.
For emergencies or instances where the exposure levels are not
known, use a full-facepiece positive-pressure, air-supplied respirator.
WARNING: Air-purifying respirators do not protect workers in oxygen-deficient
atmospheres.
B. Skin Protection:
Wear impervious protective clothing, including boots, gloves,
lab coat, apron or coveralls, as appropriate, to prevent skin
contact.
C. Eye Protection:
Use chemical safety goggles and/or full face shield where dusting
or splashing of solutions is possible. Maintain eye wash fountain
and quick-drench facilities in work area.
V. Disposal Considerations:
Whatever cannot be saved for recovery or recycling should be handled
as hazardous waste and sent to an approved waste facility. Processing,
use or contamination of this product may change the waste management
options. State and local disposal regulations may differ from
federal disposal regulations. Dispose of container and unused
contents in accordance with federal, state and local requirements.
TOXICOLOGY:
I. Experimental Toxicology:
Oral rat LD50: 25 mg/kg.
Skin rabbit LD50: 14 mg/kg
II. Acute Effects:
A. Inhalation:
Corrosive. Extremely destructive to tissues of the mucous membranes
and upper respiratory tract. Symptoms may include:
- sore throat
- coughing
- shortness of breath
- and labored breathing
Higher exposures may cause pulmonary edema.
B. Ingestion:
Corrosive. Swallowing can cause severe burns of the mouth, throat,
and stomach, leading to death. Can cause sore throat, vomiting,
diarrhea. May cause violent gastroenteritis, peripheral vascular
collapse, dizziness, intense thirst, muscle cramps, shock, coma,
abnormal bleeding, fever, liver damage and acute renal failure.
C. Skin Contact:
Corrosive. Symptoms of redness, pain, and severe burn can occur.
Dusts and strong solutions may cause severe irritation. Contact
with broken skin may cause ulcers (chrome sores) and absorption,
which may cause systemic poisoning, affecting kidney and liver
functions. May cause skin sensitization. May be absorbed through
the skin; symptoms may parallel ingestion.
D. Eye Contact:
Corrosive. Contact can cause blurred vision, redness, pain and
severe tissue burns. May cause corneal injury or blindness.
III. Chronic Effects:
Repeated or prolonged exposure can cause ulceration and perforation
of the nasal septum, respiratory irritation, liver and kidney
damage and ulceration of the skin. Ulcerations at first may be
painless, but may penetrate to the bone producing "chrome
holes."
IV. Aggravation of Pre-existing Conditions:
Persons with pre-existing skin disorders, asthma, allergies or
known sensitization to chromic acid or chromates may be more susceptible
to the effects of this material.
V. Pregnancy:
A. Effects on development:
It has an embryotoxic and/or foetotoxic effect in the animal.
It crosses the placenta in the animal.
B. Effects on reproduction:
It may cause effects in the testicles of animals.
C. Data on mother’s milk:
There are no data concerning its excretion or detection in mother’s
milk.
VI. Carcinogenic Effects:
Known to be a human carcinogen.
VII. Mutagenic Effects:
Demonstrated mutagenic effects in the animal or suspected in man.
VIII. Sensitization:
This product causes respiratory and skin sensitization.
FIRST AID MEASURE:
I. Inhalation:
Remove to fresh air. If not breathing, give artificial respiration.
If breathing is difficult, give oxygen. Get medical attention
immediately.
II. Ingestion:
If swallowed, DO NOT INDUCE VOMITING. Give large quantities of
water. Never give anything by mouth to an unconscious person.
Get medical attention immediately.
III. Skin Contact:
Immediately flush skin with plenty of water for at least 15 minutes
while removing contaminated clothing and shoes. Get medical attention
immediately. Wash clothing before reuse. Thoroughly clean shoes
before reuse.
IV. Eye Contact:
Immediately flush eyes with plenty of water for at least 15 minutes,
lifting lower and upper eyelids occasionally. Get medical attention
immediately.
ECOLOGICAL INFORMATION:
I. Environmental Fate:
When released into the soil, this material may leach into groundwater.
When released into water, this material is not expected to evaporate
significantly. This material may bioaccumulate to some extent.
When released into the air, this material may be removed from
the atmosphere to a moderate extent by wet deposition.
II. Environmental Toxicity:
No information found.
EXPOSURE LIMIT IN QUEBEC:
Valeur d'exposition moyenne pondérée (VEMP):
0,05 mg/m³ (expressed as Cr.)
References:
1. Chemical Hazards of the Workplace, Proctor & Hughes,
4th edition.
2. Clinical Environmental Health and Toxic Exposures, Sullivan
& Krieger; second edition.
3. CSST-Québec, Répertoire Toxicologique.
4. J.T. Baker, MSDS, Potassium Dichromate
5. Occupational Medicine, Zenz C., third edition.
6. Sax’s Dangerous Properties of Industrial Materials, Lewis
C., 10th edition.
7. Toxicologie Industrielle et Intoxications Professionnelles,
Lauwerys R.R., 4th edition.
Edouard Bastarache M.D. (Occupational & Environmental Medicine)
edouardb@sorel-tracy.qc.ca
http://sorel-tracy.qc.ca/~edouardb/
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