is a safe way to do all jobs
Ask yourself these questions:
- What are the worst possible things that could go wrong?
- How will I deal with them?
DO NOT perform the tasks or job
until you have the answer to these questions. Read labels and
educate yourself about the substance by reading the SDS. There
is no substitute for proper work practice and well informed laboratory
Compressed Gas Cylinders
Why Do I need to Know About Mercury?
gases present both mechanical and physical hazards. If a cylinder
valve is accidentally broken, a standard 330 cubic foot cylinder
at approximately 2600 psi becomes a rocket attaining speeds of
several miles per hour.
The contents of the cylinder may represent additional hazards
due to flammability, reactivity, toxicity or asphyxiation. Exposure
to corrosive gases such as chlorine, ammonia, and nitrogen dioxide
can do irreparable damage to the lungs. Cryogenic gases such
as liquid nitrogen can cause tissue damage from extreme cold.
The following list of prudent practices for the safe handling
and use of compressed gas cylinders is accordingly presented
for your review. Many of the practices have been incorporated
into OSHA regulations and are therefore Federal Law.
- Insure that cylinder contents are properly labeled. Do not
depend on manufacturer color codes!
- When transporting a cylinder, insure that the protective
cap is in place and securely strap the cylinder to a hand cart.
Never drag or slide the cylinder.
- Cylinders must be secured firmly at all times. Firmly belt
or chain cylinders individually to a wall, cylinder cart, cylinder
rack or rigid structure.
- Keep incompatible gas classes stored separately. Examples
would include separating flammables from reactives, which include
oxidizers and corrosives (i.e. oxygen, fluorine, chlorine).
Oxygen and nitrous oxide cylinders must be separated from flammables
or fuel gas cylinders and combustible materials by a minimum
of 20 feet, or by a 5 feet high barrier with a fire rating
of at least one half hour. Segregate gas storage from all other
- Do not expose cylinders to an open flame or to any temperature
above 125° Fahrenheit.
- Attach the regulator securely before opening the valve.
Open cylinder valves slowly. Do not use a wrench to open
or close a hand wheel type valve. If it can not be
operated by hand, it should be repaired by the vendor or
qualified individuals. Spring loaded pressure relief regulators
should be used. When used with hazardous, flammable, or
toxic gases, the valve should be vented to the fume hood.
- Under NO circumstances should oil or grease
be used on regulator valves or cylinder valves. These substances
may be reactive with some gases such as oxygen. Regulators
used with oxidizing agents must be carefully cleaned to avoid
the possibility of explosion due to contact of the gas with
any reducing agent or oil.
- Never leave cylinder valves open when not in use. Segregate
empty cylinders from full. When the cylinder is no longer in
use, shut off the valves, relieve the pressure in the gas regulators,
remove the regulator and cap the cylinder.
- Cylinders should never be emptied to a pressure lower than
170 kpa (25psi) because the residual contents may be contaminated
with air if the valve is left open.
- If a cylinder leaks and the leak can not be stopped by tightening
a valve gland or packing nut, close the leaking valve, replace
the valve cap and move the cylinder to a well ventilated area
(i.e. outdoors). Tag the cylinder as dangerous, rope
the area off, and notify a supervisor.
It is important that you know and understand the properties,
uses, and safety precautions of the gas before use. Cylinder
safety devices must be maintained in proper operating conditions
to function correctly. Only qualified, gas-supplier personnel
should service or correct associated problems with cylinders.
For further information contact the Department of Environmental
Health and Radiation Safety.
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Why Do I need to Know About Mercury?
When you work in an environment contaminated
with mercury, you quickly absorb the toxic metal. All forms
of mercury are toxic. Mercury poisoning can result from inhalation,
ingestion, and injection or absorption through the skin. Elemental
mercury poses a health hazard because it is volatile. Elemental
mercury, as a vapor, penetrates the central nervous system,
where it is ionized and trapped, attributing to its extreme
toxic effects. Elemental mercury is not well absorbed by the
gastrointestinal tract; therefore, when ingested, it is only
mildly toxic. Mercury metal and mercury compounds are highly
hazardous if inhaled or if they remain on the skin for more
than a short period of time. Dimethyl mercury rapidly penetrates
intact skin. Depending on the type of mercury and dose, symptoms
may appear relatively quickly or take a number of years to
Listed below are various forms of mercury and their effects
- Mercury vapor (i.e., elemental mercury) is
readily absorbed through inhalation and can also pass through
intact skin. After absorption, elemental mercury is carried
by the blood to the central nervous system where it is oxidized.
The oxidation product produces injury. Persons heavily exposed
to elemental mercury will develop worsening tremors of the
hands, shyness, insomnia, and emotional instability (e.g.,
the symptoms of the Mad Hatter in Alice in Wonderland--a
caricature of hat makers who cured felt in pools of mercury.)
Mercury vapors can reach very high levels when the liquid is
heated. Such levels will cause adverse effects in humans almost
immediately if workplace controls are inadequate. Some equipment,
such as thermometers, vacuum pumps, manometer, and sphygmomanometers,
may contain mercury.
- Mercury salts (e.g., mercuric nitrate) are
highly toxic and corrosive. They accumulate mostly in the kidney
causing renal damage.
- Organo-mercury compounds attack the nervous
system causing tremors, impaired vision and hearing, and paralysis.
These compounds may also cause birth defects. The effects from
exposure to excessive levels of airborne mercury or skin contact
with mercury compounds may not be noticeable for months or
- Mercury fulminate, Hg(ONC) 2, is a detonator
used in explosives.
- Mercury(II) oxide is an oxidizer. It can
cause organic materials to start burning in the same manner
as any strong oxidizer.
- Dimethyl mercury, an extremely toxic material,
is a colorless, sweet-smelling liquid. It is a severe fire
hazard, with a flash point of -4°C. This material rapidly
penetrates the skin resulting in severe exposure from very
minor quantities, which can be fatal. Extreme caution is required
when working with this material and when selecting personal
protective equipment (PPE).
When a mercury spill occurs, please contact Environmental Health
and Radiation Safety Office at X48749.
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Safety audits are essential and basic tool for establishing
and maintaining safe conditions and finding unsafe practices
in the workplace. Safety audits are a practical ways to identify
and correct unsafe conditions. Environmental Health and Safety Office perform safety audits biannually. Each time a laboratory
is audited, a report will be sent to Principle Investigator and
a follow- up audit will be conducted by the Laboratory Safety
Officer to ensure that efforts were made to correct problem
stated in the audit.
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