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Beryllium Monoxide Toxicology

Identification :


 

CAS number : 1304-56-9

UN number : UN1566

Molecular formula : BeO

Molecular weight: 25.01

 

Main Synonyms:

 

French Names :

Oxyde de béryllium

Oxyde de glucinium (old appellation)

English Names :

Beryllia,

Beryllium oxide,

Beryllium monoxide.

 

Uses and Sources of Emission
:

-in ceramics,

-in electronics and micro-electronics,


-in the manufacture of glass,

-as chemical catalyst,

-as regulator in nuclear reactors,


-as refractory material in the
metallurgy of rare earths,

-in high power laser tubes,

-in microwave telecommunication systems
and as components of microwawe ovens,

-in windows of X-ray transmitters used
under extreme conditions,

-etc.

 

Hygiene and Safety
:

 

I-Appearance :

Beryllium oxide is a solid crystal or a
fine amorphous, white and odourless powder according to the heat
treatment at the time of preparation.

 

II-Physical Properties
:

 

Odor : None

Color : White

Physical State : Solid

Melting Point (F) : 2547 (BeO)

Solubility (BeO) : None

Density (g/cc) : 2.86 (BeO)

 

III-Inflammability :


This product is non flammable.

 

IV-Explosiveness
:

Heating of beryllium oxide with
magnesium powder can cause an explosive reaction.

 

V-Techniques and Means for
Extinguishing Fire :

Use any means appropriate for the
surrounding materials.

Special techniques:

Beryllium monoxide released from a
beryllium fire is very toxic: wear an autonomous respiratory
protection gear and protective clothing covering all of the body.


After a beryllium fire, decontamination
must be carried out by qualified personnel.

 

VI-Products of Combustion
:

Beryllium oxide does not burn

 

Prevention :


 

I-Protection Means :


When engineering measures and
modifications of working methods are not sufficient to reduce the
exposure to this substance, the wearing of an individual
protection apparatusr can be necessary.

These protection gears must be in
accordance with the regulation.

 

II-Respiratory Protection
:

In the presence of powder or dust of
beryllium oxide, wear a respiratory protection apparatus if the
concentration in the work environment is higher than the action
level and even when the exposure is lower than this one.

 

III-Skin Protection
:

Wear skin protection. The choice of a
skin protection gear depends on the nature of the work to carry
out. In the presence of powder or dust of beryllium oxide, wear
protective clothing covering all of the body.

 

IV-Ocular Protection :


Wear ocular protection. The choice of an
ocular protection gear depends on the nature of the work to carry
out and, if it is necessary, of the type of respiratory protection
gear used.

 

Reactivity :


 

I-Stability :

This product is stable under normal
conditions of use.

 

II-Incompatibility
:

Heated in the presence of magnesium, it
reacts violently and can produce an explosion.

 

III-Decomposition Products :


None, this product is stable even at its
melting point (2 530 °C).

 

Handling :


 

I-When possible, use substitution products having
less harmful effects, or a wet process.

II-Avoid any operation or process which can produce
fine particles or a cloud of dust.

III-Favour containment of processes, consider and
install aspiration at the source.

IV-Reduce the number and the surface of the areas
where there is a risk of exposure to beryllium and its compounds,
just as the number of workers having access to these areas.

V-Use high efficiency filter vacuum cleaners
against particles (HEPA) to clean the equipment and the floor of
the working area.

VI-Avoid any skin and ocular contact.

VII-
Do not eat and do not drink while using this product.

VIII-Observe very strict personal hygiene. Wash and
change clothing after work.

IX-Completely separate town and working clothes
(Double locker). Protection gears and working clothes including
shoes, should not leave the workplace.

X-Double lockers should be available to workers,
one for work clothes, the other for personal clothes.

 

Storage :

Store away from places where fire
hazards are high, away from incompatible products, in a cool and
well ventilated place. Moreover, if the product is in the form of
powder, store in a tight container, well identified.

 

Leaks :

 

I-Because of its toxicity, every precaution must be
taken to avoid a leak or a spill of this product.

II-If the product is used as particules or if there
is dust, establish a limited access zone and limit access until
cleaning is completed. Cleaning should be carried out only by
qualified personnel.

III-Do not touch damaged containers or leaked
products without wearing protective clothing covering all of the
body and an autonomous respiratory protection gear.

IV-Prevent the formation of clouds of dust.

V-Collect dust by using a wet process or a high
efficiency filtering vacuum cleaner against particles (HEPA).


VI-Collect in a hermetic container duly identified
by using a suitable technique in order to prevent the
contamination of the area.

 

Waste Disposal :


 

This product should not be dispersed
into the environment. Beryllium oxide wastes in the form of powder
or dust must be recovered in a sealed container identified and
handed over to a firm which recycles it. If necessary, consult
concerned regional authorities.

 

Toxicology
:

 

I- Toxicokinetics :

 

A-Absorption :

 

1-Pulmonary Absortion :

An exposure to airborne beryllium in
excess of the occupational standard can occur :

A-When powdered beryllium oxide is handled.

B-In
metallurgy, if beryllium-containing materials are melted or casted
and at the time of handling of slags and scum.

C-When abrasive cutting, machining, grinding,
sanding, polishing or crushing pieces containing beryllium oxide.


D-When heat treating metal pieces containing
beryllium or at the time of any process implying heating, such as
welding or cutting with a blowtorch.

E-At
the time of maintenance, cleaning or repairing equipment
contaminated such as furnaces, tanks or boilers in sectors such as
petroleum, metallurgy or energy.

F-When sorting, handling or recycling electronic
parts intended for recovery.

G-Volatile beryllium hydroxide can be formed when
firing solid BeO parts at temperature greater than 900 oC in a
moist atmosphere such as in a hydrogen atmosphere sintering
furnace.

 

a-Insoluble compounds :

The pulmonary clearance occurs very
slowly. What was not eliminated quickly, by the mucociliary
activity or phagocytosis of the particles, is retained several
months in the lungs and is gradually released into the blood.


b-Soluble compounds :

The pulmonary clearance occurs quickly
by dissolution in the pulmonary fluids and a variable proportion
passes into blood.

c-Pulmonary clearance of
low temperature calcined beryllium
oxide would be faster than that
of high temperature calcined
beryllium oxide because of its
greater solubility.

 

2-Skin Absorption :

Beryllium and its compounds are
practically not absorbed through intact skin because they bind to
components of the skin (proteins and nucleic acids) to form lowly
diffusible complexes. However, it is thought that skin contact can
especially play a part in sensitizing following exposure to fine
particles.

 

3-Digestive Absorption :

Beryllium and its compounds are only
very slightly absorbed by the digestive tract. The absorbed amount
depends on the dose and the solubility of the compounds. This
amount is limited by the formation of insoluble colloidal
phosphates in the intestine.

 

B-Distribution :

Absorbed beryllium compounds, are
transported in the body adsorbed on plasmatic proteins in the form
of colloidal phosphate. In the
short run, they tend to
accumulate in the liver especially in the cases of important
exposures. In the long
run, one finds them mainly in the
lymphatic ganglia and the bones. They were also identified in the
blood of the umbilical cord and maternal blood.

 

C-Metabolism :

Beryllium and its compounds are not
metabolized. In the lungs, soluble beryllium salts are partially
transformed into insoluble salts.

The beryllium ion inhibits in a
competitive way many enzymes activated by magnesium or manganese,
in particular alkaline phosphatase.

The immunological action probably goes
through the formation of a beryllium-protein complex, because of
the small molecular weight of beryllium.

 

D-Excretion :

Compounds absorbed into the body are
excreted mainly in the urine. Compounds which are not absorbed
into the body are excreted mainly in the feces following ingestion
by the oral route or by the pulmonary mucociliary clearance, and
the excretion depends on the solubility of the ingested compounds.


Beryllium compounds have also been
identified in mother's milk and colostrum.

Mobilization and excretion can continue
during several years and persist a very long time after the
cessation of exposure.

There is no obvious correlation between
the presence or the severity of berylliosis and the urinary
beryllium level.

 

E-Half-Life :

There are no precise data in human
beings but, one can say that in general according to animal
studies, the insoluble or not very soluble compounds and the
soluble compounds, are cleared from the pulmonary tissue in a
biphasic way initially with a half-life of a few days during which
30 to 50 % of the beryllium is eliminated.

The second phase which varies according
to the solubility of the compounds suggests that the half-life of
the soluble compounds is of about a few weeks or a month while it
varies from months to years for the compounds which are little or
not soluble.

The half-life in the whole body
can be several years.

 

F-Biological Data :

An exposure to 2 µg/m³ of
beryllium in the air corresponds to approximately 7 µg/L. in
the urine and 4 µg/L. in the blood. For a non-professionally
exposed population the urinary beryllium concentration is less
than 0,9 µg/l.

The EPA (USA ) has estimated that the
total amount of beryllium absorbed daily by the general population
is 423 ng following the inhalation of ambient air and from the
ingestion of food and water. The most important contribution comes
from the ingestion of water (300 ng) and food (120 ng).

 

G-Sensitive Population :

Several studies suggest that genetic
susceptibility can play an important role in the development of
berylliosis. People suffering from chronic berylliosis are
carrying more frequently than controls a genetic marker :




(HLA-DPB1 Glu69). This allele would be present in 85 to 95% of the
patients and in only 30 to 45 % of the controls.

 

II-Acute Effects
:

 

A-Inhalation :

 

1-Acute Tracheo-Bronchitis
:

It is benign and heals in one to four
weeks.

2-Chemical Pneumonitis :

Ambient concentrations above 25
µg/m³ beryllium are usually associated with this acute
form, but these exposures are rare nowadays.

It can occur within 72 hours after a
massive exposure to low
temperature calcined beryllium oxide. This was not reported following exposure to
high temperature calcined
beryllium oxide.

a-Symptoms :

The following symptoms were reported :


- cough,

- sensation of retrosternal burning,


- increasing dyspnea,

- effects on the general state resulting
in :

* light fever,

* feeling of weakness

* tiredness,

- cyanosis.

b-Evolution :

It can be fulgurating with complications
such as pulmonary oedema and fibrosis.

c-Prognosis :

Death :

Fatalities were reported.

Recovery :

Recovery occurs in 85 to 90 % of the
cases. Convalescence can vary from 4 to 6 months.

Chronicity :

The acute form can also progress to the
chronic form.

 

B-Skin Contact :

The incrustation of small crystals or
chips of beryllium oxide under the skin can cause the formation of
painless ulcers or subcutaneous granulomas after a few
months.

 

C-Ocular Contact :

The damage can result from irritation by
particles or by the mechanical action of dusts or of the
particles. Exposure can result from the direct contact with
airborne particles (particles, dusts, or powders), or following
ocular contact with the hands or soiled clothing.

 

III-Chronic Effects :


 

Berylliosis :

 

A-Introduction :

Berylliosis develops in 2 to 15 % of
workers exposed according to the kind of work carried out. The
appearance and the progression of the disease are partly due to
individual genetic
susceptibilities which act in
connection with the exposure.

 

B-Exposure :

Prolonged exposure, even to very weak
beryllium concentrations or to its compounds can cause
berylliosis. The low temperature
(500°C) calcined beryllium oxide would be more sensitizing that the
high temperature (1 000°C)
calcined beryllium oxide because
of its greater solubility.

 

C-Physio-Pathology :

The first action is inflammation which
creates a ground favourable to the development of a cellular
mediated immunological response. Beryllium acts in combination
with peptides as a hapten which activates the effector cells to
produce cytokins. These last ones stimulate the inflammatory and
immunizing reaction of various pulmonary cells while acting on the
development of the granulomatous inflammation associated with
chronic berylliosis.

 

D-Latency :

It is an insidious disease which can
appear a few months only after the beginning of the exposure or
several years after the end of an exposure having lasted only a
few months. Usually the disease appears within a delay varying
from a few months to 5 years, seldom up to 20 or 30 years.

 

E-Stages of Chronic Berylliosis
:

1-Sensitizing to Beryllium :


Demonstrated by two BeLPT abnormal
tests,

2-Sub-Clinical Berylliosis
:

A certain evidence of pulmonary effects,
but without symptom,

3-Chronic Berylliosis
:

Evidence of pulmonary effects with
symptoms.

 

F-Symptomatology :

At the beginning :

-exertional dyspnea,

-dry and irritating cough, more severe
in the morning or upon exertion, accompanied by chest pain and a
feeling of tiredness.

In the more advanced cases :

-fever or night sweats,

-anorexia accompanied by a progressive
loss of weight,

-articular pains.

One can also observe :

-cyanosis,

-digital hippocratism,

-enlargement of the liver and the
spleen,

-adenopathy,

-cardiomyopathy

-renal effects.

The pulmonary effect is characterized by
the formation of non-caseous granulomas accompanied by alveolitis.
When the effect progresses, diffuse interstitial fibrosis
settles.

 

G-Complications :

Complications can occur such as
spontaneous pneumothorax and cardiopulmonary diseases.

 

H-Exacerbation :

The disease can be exacerbated by
factors such as a re-exposure, infection, surgical operation,
pregnancy, etc.

 

I-Evolution :

The evolution of the disease can occur
in a gradual way, but can also be very variable.

Complete cure remains exceptional. A
minority of people remains asymptomatic for long periods of time,
while the majority presents symptoms, while carrying out an almost
normal life.

The evolution of the disease can end in
cardiorespiratory insufficiency (cor pulmonale) causing death in
the most advanced cases.

 

J-Conditions Aggravated by Exposure
:

People with deteriorations of the
pulmonary function, airway diseases, or conditions such as asthma,
emphysema, chronic bronchitis, etc can incur more deterioration if
dust or vapors are inhaled.

If former diseases or damage to the
neurological, circulatory, hematologic, or urinary systems have
already occurred, suitable sreening examinations should be carried
out in individuals who can be exposed to hazards when handling and
using this material

 

K-Medical Surveillance :

 

1-Biological Monitoring of the
Exposure :

 

A- Beryllium lymphocyte proliferation
(BeLPT) :

-As a monitoring blood test, it is more
sensitive than clinical evaluation and has a great predictive
value in spite of its limitations.

-When it is performed on cells coming
from bronchoalveolar lavage, the predictive value is nearly 100 %
of the cases, but this test is less frequent because the sampling
requires a more invasive procedure.

-A negative test does not exclude the
possibility of sensitization or berylliosis, particularly in
smokers.

-The BeLPT test can help to make the
distinction between berylliosis and other pulmonary diseases,
particularly sarcoidosis.

-The use of BeLPT as a test for
berylliosis monitoring has identified a population of workers
sensitized without apparent symptom of the disease. These
sensitized workers had pulmonary function tests, a tolerance to
exercise, pulmonary X-rays and biopsies that were normal.

In this type of situation, these cases
must remain under medical supervision and be re-examined at
regular intervals to detect the first signs of the disease.
It is estimated that annually,
approximately 10 % of the sensitized individuals, will develop the
disease.

 

B-Periodicity :

Certain researchers mention that BeLPT
monitoring should be conducted periodically among workers exposed
to beryllium, every 2 to 5 years, according to the level of
exposure.

 

C-Follow-up :

A medical follow-up must be performed in
sensitized workers every 1 to 2 years and immediately in workers
with subclinical impairment, or sensitized with symptoms or
unexplained pulmonary disease.

 

2-Other Suggested Test
:

Pulmonary radiography can identify a
certain number of cases that the (BeLPT) missed, the blood test
detecting about from 80% to 90% of the cases.

 

L-Treatment :

There is no treatment to cure
berylliosis. However, certain drugs are effective to reduce the
effects and to slow down the progression of the disease. The use
of these drugs, usually corticosteroids, must be permanent.


For the sensitized or asymptomatic
workers, the use of drugs is not necessary, but they must be the
subjects of a medical follow-up in order to evaluate the
progression of the disease.

 

IV-Skin Sensitization
:

This product is a skin sensitizer.
Several cases of dermatitis of the allergic type (eczema) were
reported in workers exposed to beryllium and its compounds. These
cases were confirmed by skin patch tests with several beryllium
salts (sulphate, fluoride, chloride and others).

 

V-Pregnancy :

 

A-Effects on development :


It crosses the human placental
barrier.

B-Effects on reproduction
:

The available data do not make it
possible to make an adequate evaluation of the effects on
reproduction.

C-Data on breast milk
:

It is found in the breast milk of
animals..

 

VI-Cancerogenic Effects
:

Human carcinogen confirmed by I.A.R.C.,
A.C.G.I.H., N.T.P.

 

VII-Mutagenic Effects
:

The available data do not make it
possible to make an adequate evaluation of mutagenic effects. The
tests of DNA effects and of cellular transformation proved to be
positive for low temperature calcined beryllium oxide whereas
doubtful results were obtained in the same tests for high
temperature calcined beryllium oxide.

 

First aid :


 

I-Inhalation :

In the event of inhalation of fume or
dust, bring the person into a ventilated place and place him in a
half-sitting position. If he does not breathe, give him artificial
respiration. In the event of respiratory difficulties, give him
oxygen.

Transfer immediately to the nearest
medical emergency department.

II-Ocular Contact :

Rinse eyes with plenty of water during 5
minutes or until the product is removed.

If irritation persists, see a doctor.


III-Skin Contact :

Quickly withdraw contaminated clothing.
Wash the skin with water and soap. Completely clean cuts or
wounds. Any beryllium oxide particle lodged accidentally under the
skin must be removed.

IV-Ingestion :

Rinse mouth with water.

See a doctor.

 

Quebec's Exposure Limit
:

 

I-Valeur d'Exposition Moyenne
Pondérée (VEMP) :

0,00015 mg/m³ (expressed as Be
(Beryllium).

 

II-Notes :

C2 : A suspected human carcinogen.


EM : Exposure to this chemical must be
reduced to the minimum.

RP : Substance whose recirculation is
prohibited


 

References :

 

1-Occupational Medicine,Carl Zenz,
last edition.

2-Clinical Environmental Health and
Toxic Exposures, Sullivan & Krieger; last edition.

3-Sax's Dangerous Properties of
Industrial Materials, Lewis C., last edition.

4-Toxicologie Industrielle et
Intoxications Professionnelles, Lauwerys R. last
edition.

5-Chemical Hazards of the Workplace,
Proctor & Hughes, 4th edition.

6-CSST-Quebec, Répertoite
Toxicologique.

7-ESPI Metals MSDS, 1996 (Prepared
par S. Dierks)

By Edouard Bastarache

Related Information

Links

Materials Beryllium Oxide
Typecodes Article by Edouard Bastarache
Edouard Bastarache is a well known doctor that has written many articles on the subject of toxicity of ceramic materials and books on technical aspects of ceramics. He writes in both English and French.

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