Crash course for working with gases

java · Consumer

This was collected from the WD, regarding safety when working with gases.............java
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Insipid Bucket of Drool
~Chairman of the Bored~

Posted - Feb 19 2005 : 01:15:13 AM

Detection of these gases via smell is unreliable and highly dangerous,

Complete olfactory failure is definately possible!

In order to cover all the bases SWIBOD has hashed out a standard safety crash course,

Any bee even thinking of working with these gases should memorize the following info!

Hydrogen Cyanide (HCN) is a colorless gas with a faint, bitter, almond-like odor.

While Hydrogen Sulphide (H2S) has a pungent rotten egg odor.

They both express an affinity for Fe that rapidly attacks the iron in the blood stream.

The most important toxic effect of these gases is by inhibiting the metal-containing enzymes.

One such enzyme is cytochromoxidase, which contains iron.

This enzyme system is responsible for the energy-providing processes in the cell where oxygen is utilized, i.e., cell respiration.

When cell respiration ceases, it is no longer possible to maintain normal cell functions, which may lead to cell mortality.

There is no medically excepted antidote against this type of poisoning, and the poisoning is further compounded by potentially long term side effects.

The treatment given to exposed patients is based on encouraging and speeding-up the body's own ability to excrete cyanide (or sulphides) and to bind cyanide (or sulphides) in the blood.

The enzyme rhodanese is present in the body, mainly in the liver, and together with sulphur transforms cyanide into thiocyanate, which is passed out in the urine.

By supplying sulphur in the form of Sodium Thiosulphate (Na2S2O3) HCN detoxification can be speeded up.

Oxygen therapy is used in the event of low level exposure to restore concentrations of oxygen in the blood.

In the event of severe H2S poisoning 300mg Sodium Nitrile in a 10ml solution must be delivered by IV within 30 minutes, immediate delivery is preferable to be most effective.

Sodium Nitrile is also effective in HCN recovery, but not approved by the FDA as an antidote.

Amyl nitrite is another "non approved antidote" commonly used in the case of exposure to either.

Amyl nitrite is a commonly abused substance, and therefore slightly regulated;

It is also known on the street as poppers, butyl nitrate, TNT, liquid gold, rush, ram, thrust, rock hard, kix.

Here's SWIBOD's H2S References-

Human Toxicity Values:

Man: severe toxic effects 200 ppm = 280 mg/cu m 1 min; symptoms of illness 50 ppm = 70 mg/cu m; unsatisfactory: 20 ppm = 28 mg/cu m
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 745]

Man: lethal: 600 ppm/30 min; 800 ppm, immediate /lethality/
[Verschueren, K. Handbook of Environmental Data of Organic Chemicals. 2nd ed. New York, NY: Van Nostrand Reinhold Co., 1983. 745]

Lethal blood concentration: 0.092 mg %.
[Winek, C.L. Drug and Chemical Blood-Level Data 1985. Pittsburgh, PA: Allied Fischer Scientific, 1985.]

Toxicology References:

Low concentrations of 20-150 ppm cause irritation of the eyes; slightly higher concentrations may cause irritation of the upper respiratory tract, and if exposure is prolonged, pulmonary edema may result. The irritant action has been explained on the basis that hydrogen sulfide combines with the alkali present in moist surface tissues to form sodium sulfide, a caustic.
[Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996. 1843]

The direct action of H2S on mucous membranes is usually observed first by symptoms of eye irritation, resulting from local inflammation of the conjunctiva and cornea. Acute inflammation of conjunctiva accompanied by lacrimation and mucopurulent exudate is not uncommon. In severe cases, corneal erosion with blurred vision may also occur. Occasionally, corneal ulceration may occur, resulting in impaired vision. Since the cornea is affected together with the conjunctiva in many instances, keratoconjunctivitis rather than conjunctivitis more accurately describes the ophthalmologic effects of H2S exposure. In general, irritation of the eyes occurs at a concentration of H2S of 50 ppm; however, conjunctivitis or "sore eyes" have been observed upon exposures in the range of 5-100 ppm.
[Sullivan, J.B. Jr., G.R. Krieger (eds.). Hazardous Materials Toxicology-Clinical Principles of Environmental Health. Baltimore, MD: Williams and Wilkins, 1992. 713]

As concentrations approach 100 ppm,...odor becomes imperceptible because of olfactory fatigue. At these levels, the gas disrupts cellular respiration and may cause profound respiratory depression as well as cardiac dysrhythmias.
[Zenz, C., O.B. Dickerson, E.P. Horvath. Occupational Medicine. 3rd ed. St. Louis, MO., 1994 886]

At a concentration of 150 ppm, the olfactory nerve is paralyzed.
[USEPA; Health and Environmental Effects Profile for Hydrogen Sulfide p.118-8 (1980) ECAO-CIN-026A]

Prolonged exposure may cause pulmonary edema at 250 pp.
[Sullivan, J.B. Jr., G.R. Krieger (eds.). Hazardous Materials Toxicology-Clinical Principles of Environmental Health. Baltimore, MD: Williams and Wilkins, 1992. 712]

Hydrogen sulfide is an extremely hazardous gas which can be immediately life threatening at high concentrations (300 mg/cu m or 200 ppm).
[NIOSH: Occupational Exposure to Hydrogen Sulfide p.79 (1977) DHEW (NIOSH) Publication -- 77-158]

The following reference seems more optimistic

Concentrations of 20-50 ppm irritates the eyes. Inhalation of 500 ppm for 30 minutes produces headache, dizziness, excitement, staggering, and gastroenteric disorders followed in some cases by bronchitis or bronchial pneumonia. Concentrations above 600 ppm can be fatal within 30 minutes through respiratory paralyses.
[Matheson; Guide to Safe Handling of Compressed Gases 2nd ED p.15 (1983)

Exposure References:

In the 19th century, deaths from acute exposure to hydrogen sulfide portended permanent brain injury from non-lethal /exposures/. The neurobehavioral effects of H2S exposures lasting from moments to years were compared in 16 healthy subjects, 2 yr to 22 yr afterward. Neurophysiologic and psychologic tests were used to appraise mood status and frequencies of 35 symptoms. Functions and frequencies, described as percent predicted adjusted for age, sex, educational achievement, and other factors, were compared with those in an unexposed population. ... Frequencies were elevated for 31 of 33 symptoms. Balance was impaired (246% predicted with eyes closed, 159% predicted with eyes open), and simple and choice reaction times were prolonged (151% and 130% predicted, respectively). Visual fields performance was decr to 72% predicted (right) and 55% predicted (left), color discrimination was abnormal, and hearing was decr.Psychologic domains showed cognitive disability, reduced perceptual motor speed, impaired verbal recall and remote memory, and abnormal mood status. ...
[Kilburn KH; South Med J 90 (10): 997-1006 (1997)]

Respiratory symptoms and lung function in relation to hydrogen sulfide exposure was assessed in oil and natural gas workers in Alberta, Canada. 175 workers were questioned about gas exposures strong enough to cause respiratory symptoms and those that caused loss of consciousness (knockdowns); assessments included spirometry and skin prick testing. Exposures strong enough to cause symptoms were reported by 34% of the workers. These exposures were not associated with lower spirometric values or incr prevalence of symptoms. Exposures strong enough to cause unconsciousness were reported by 8% of the workers. while these knockdowns were not associated with lower spirometric values, they were associated with excesses of shortness of breath while hurrying, wheeze with chest tightness, and attacks of wheeze. Respiratory symptoms were consistent with bronchial hyperactivity. ...
[Hessel PA, et al; Amer J Indust Med 31 (5): 554-7 (1997)]

A CASE OF POLYNEURITIS AND ENCEPHALOPATHY FROM 1 DAY EXPOSURE TO A CONCN INSUFFICIENT TO CAUSE LOSS OF CONSCIOUSNESS HAS BEEN REPORTED.
[American Conference of Governmental Industrial Hygienists. Documentation of the Threshold Limit Values and Biological Exposure Indices. 5th ed. Cincinnati, OH:American Conference of Governmental Industrial Hygienists, 1986. 318]

HYDROGEN SULFIDE IS ASSOCIATED WITH DEATHS CAUSED BY FERMENTING MANURE.
[MORSE DL ET AL; JAMA 25 (1): 63-4 (1981)]

SPONTANEOUS ABORTIONS WERE ANALYZED IN AN INDUSTRIAL COMMUNITY IN FINLAND IN WOMEN WHO WERE EMPLOYED IN RAYON TEXTILE JOBS AND PAPER PRODUCTS JOBS. AN INCREASED RATE OF SPONTANEOUS ABORTIONS WAS NOTED IN ALL SOCIOECONOMIC CLASSES IN AREAS WHERE THE MEAN ANNUAL LEVEL OF HYDROGEN SULFIDE EXCEEDED 4 UG/CU M. HOWEVER, THE DIFFERENCE (TOTAL RATES 7.6 AND 9.3, RESPECTIVELY) WAS NOT STATISTICALLY SIGNIFICANT.
[HEMMINKI K, NIEMI ML; INT ARCH OCCUP ENVIRON HEALTH 51 (1): 55-63 (1982)]

Antidote References:

NITRITE AS AN ANTIDOTE FOR ACUTE HYDROGEN SULFIDE INTOXICATION CAN ONLY BE EFFECTIVE WITHIN THE FIRST FEW MINUTES AFTER THE EXPOSURE, AT WHICH TIME RESUSCITATION AND/OR VENTILATION OF THE VICTIM ARE LIKELY TO PRODUCE CONDITIONS IN WHICH THE NITRITE ACTUALLY SLOWS SULFIDE REMOVAL /SRP: DUE TO DECR BINDING OF THE SULFIDE TO METHEMOGLOBIN/.
[BECK JF ET AL; AM J IND HYG ASSOC J 42 (11): 805-9 (1981)]

Immediately remove person from exposure and ensure that the airway is clear. Given 100% oxygen by tight-fitting oronasal mask or endotracheal tube. Hyperbaric oxygen at 3 atm has been successful.
[Zenz, C., O.B. Dickerson, E.P. Horvath. Occupational Medicine. 3rd ed. St. Louis, MO., 1994 667]

A CASE REPORT OF A 34-YEAR-OLD MALE RENDERED UNCONSCIOUS BY EXPOSURE TO A HIGH CONCENTRATION OF HYDROGEN SULFIDE FUMES IS PRESENTED TO ILLUSTRATE THE ADVANTAGES OF OXYGEN THERAPY. SIGNIFICANT IMPROVEMENT IN BLOOD GASES WAS ACHIEVED WITHIN 1 HOUR OF STARTING OXYGEN. THE RISKS OF NITRITE THERAPY ARE DISCUSSED.
[RAVIZZA G ET AL; VET HUM TOXICOL 24 (AUG): 241-2 (1982)]

For basic treatment: Establish a patent airway. Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline during transport ... . Treat with rapid rewarming techniques ... if frostbite occurs. /Hydrogen sulfide and related compounds/
[Bronstein, A.C., P.L. Currance; Emergency Care for Hazardous Materials Exposure. 2nd ed. St. Louis, MO. Mosby Lifeline. 1994.,p. 391-2]

For advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious or in respiratory arrest. Positive-pressure ventilation techniques with a bag-valve-mask device may be beneficial. Monitor cardiac rhythm and treat arrhythmias if necessary ... . Start an IV with D5W TKO /SRP: To keep open, "minimal flow rate"/. Use lactated Ringer's if signs of hypovolemia are present. Watch for signs of fluid overload. Consider drug therapy for pulmonary edema ... . For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of pulmonary edema. Consider vasopressors to treat hypotension without signs of hypovolemia ... . Treat seizures with diazepam (Valium) ... . In severe cases use amyl nitrite and sodium nitrite ... as described for cyanide poisoning; omit the sodium thiosulfate injection. Early administration will be the most effective. DIRECT PHYSICIAN ORDER ONLY ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Hydrogen sulfide and related compounds/
[Bronstein, A.C., P.L. Currance; Emergency Care for Hazardous Materials Exposure. 2nd ed. St. Louis, MO. Mosby Lifeline. 1994. 392]

In two separate incidents, 6 patients were poisoned with hydrogen sulfide (H2S) in sewer gas. In the first incident, mixing acid and sodium hydroxide based drain cleaners in a confined space resulted in 4 poisonings and 2 deaths. Three ... rescuers were seriously poisoned and 1 died. Two survivors had neurological sequelae. Sodium nitrite appeared to have some clinical efficacy in 1 case. The second incident involved 2 patients working on a pump in a sewage pond. A patient lying on a raft close to the pond was seriously poisoned; sodium nitrite was clinically efficacious and this patient survived without developing neurological sequelae. Sodium nitrate /needs/ further clinical study as a potential H2S antidote.
[Halll AH, Rumack BH; Vet Hum Toxicol 39 (3): 152-4 (1997)]

A worker in a chemical synthetic factory had a presumed acute hydrogen sulfide intoxication and suffered from repetitive generalized tonic convulsions, cyanosis, shock and respiratory arrest. Dramatic response was obtained with amyl nitrate inhalation followed by intravenous administration of sodium nitrate and sodium thiosulfate. The rapid recovery without medical and neurological sequelae supports the efficacy of nitrite treatment in acute hydrogen sulfide intoxication.
[Huang CC, Chu NS; J Formosan Med Assoc 86 (9): 1018-20 (1987)]

quote:

HYDROGEN SULFIDE, from the HSDB Chemical Record.

Life Support:

o This overview assumes that basic life support measures
have been instituted.
Clinical Effects:

SUMMARY OF EXPOSURE
0.2.1.1 ACUTE EXPOSURE
o Hydrogen sulfide is a highly toxic, flammable,
colorless gas produced by decaying organic matter and
has a characteristic odor of rotten eggs at low
concentrations however, the sense of smell is paralyzed
at airborne levels above 50 to 150 ppm.
1. Exposure to concentrations of near 250 ppm causes
irritation of mucous membranes, conjunctivitis,
photophobia, lacrimation, corneal opacity, rhinitis,
bronchitis, cyanosis, and acute lung injury.
2. At concentrations of 250 to 500 ppm, signs and
symptoms include headache, nausea, vomiting, diarrhea,
vertigo, amnesia, dizziness, apnea, palpitations,
tachycardia, hypotension, muscle cramps, weakness,
disorientation, and coma.
3. At concentrations of 750 to 1000 ppm, victims may
experience abrupt physical collapse or "knock down".
Higher concentrations may also result in result in
respiratory paralysis, asphyxial seizures, and death.
The mortality rate is in the range of 6 percent.
a. Characteristics of a fatal exposure are rapid "knock
down," respiratory depression, tremors, blurred
vision, cyanosis, seizures and tachycardia.
VITAL SIGNS
0.2.3.1 ACUTE EXPOSURE
o Patients may acutely present with bradycardia,
tachycardia, hyperventilation, respiratory depression
even to the point of apnea, and/or hypo-/hypertension.
HEENT
0.2.4.1 ACUTE EXPOSURE
o Injection of the conjunctivae, seeing colored halos,
ocular pain, corneal bullae, blurred vision and
blepharospasm may be noted following exposure to 150 to
300 ppm.
0.2.4.2 CHRONIC EXPOSURE
o Rhinitis may be seen with chronic exposure.
CARDIOVASCULAR
0.2.5.1 ACUTE EXPOSURE
o Tachycardia, bradycardia, cardiac dysrhythmias, and
either hyper or hypotension may be seen.
RESPIRATORY
0.2.6.1 ACUTE EXPOSURE
o Respiratory depression, cyanosis, pulmonary edema,
bronchitis, and dyspnea may be noted following exposure
to non-fatal concentrations.
o Exposure to high concentrations will result in rapid
respiratory paralysis leading to sudden collapse.
NEUROLOGIC
0.2.7.1 ACUTE EXPOSURE
o Asphyxial seizures, coma, and death associated with
rapid respiratory paralysis may be noted following
exposure to high concentrations.
o Headache, sweating, vertigo, anosmia, irritability,
staggering gait, disorientation, somnolence, weakness,
confusion, and delirium may be noted following exposure
to non-fatal levels.
GASTROINTESTINAL
0.2.8.1 ACUTE EXPOSURE
o Nausea and vomiting may be noted. Weight loss can be
seen with chronic exposure.
GENITOURINARY
0.2.10.1 ACUTE EXPOSURE
o Exposure may rarely cause albuminuria, cylindruria, and
hematuria.
ACID-BASE
0.2.11.1 ACUTE EXPOSURE
o Transient lactic acidosis may be noted following
significant exposure.
DERMATOLOGIC
0.2.14.1 ACUTE EXPOSURE
o Skin exposure may result in severe pain, itching, and
erythema, especially in moist areas. Cyanosis may be
noted following severe exposure.
REPRODUCTIVE HAZARDS
o Spontaneous abortions have occurred after exposure to
life-threatening concentrations.
CARCINOGENICITY
0.2.21.2 HUMAN OVERVIEW
o In Rotorua, New Zealand (an active geothermal zone
where hydrogen sulfide is released to the atmosphere),
cancer deaths were not related to the extent of
hydrogen sulfide exposure and there was no overall
excess mortality found.
GENOTOXICITY
o Hydrogen sulfide exposure was associated with an
increased risk of chromosome aberrations in chemical
workers. Other factors may be involved in these
multiply-exposed cohort populations.
Laboratory:

o Monitor vital signs. Monitor pulse oximetry and/or
arterial blood gases and chest radiograph in patients
with respiratory signs or symptoms.
o Measuring blood sulfide or thiosulfate levels may be done
to document the exposure but are not useful for emergent
diagnosis or to guide emergency treatment.
o Monitor methemoglobin levels if nitrite antidotes are
administered.
Treatment Overview:

SUMMARY EXPOSURE
o Move the victim to an area of fresh air and immediately
provide respiratory support using 100 percent humidified
oxygen.
o Although its efficacy is still unproven, nitrite therapy
is recommended if it can be started early.
o Hyperbaric oxygen may be given to those who continue to
be symptomatic after standard therapy.
o Measures should be taken to control seizures, pulmonary
edema, and arrhythmias and to correct hypotension.
o Exposed mucocutaneous surfaces should be thoroughly
washed with copious amounts of water and/or soap.
o Rescuers should wear a self-contained breathing
apparatus, special chemical protective clothing, and a
safety line during rescue operations. Many would-be
rescuers have become victims when entering contaminated
enclosed areas without proper protective equipment.
o Observe for delayed onset (up to 72 hours) acute
respiratory effects.
ORAL EXPOSURE
o Hydrogen sulfide is a gas at room temperature (Harbison,
1998), making ingestion unlikely.
INHALATION EXPOSURE
o IMMEDIATELY MOVE PATIENT TO FRESH AIR AND ADMINISTER 100
PERCENT OXYGEN. PREVENT SELF-EXPOSURE and possible
death by wearing a self-contained breathing apparatus to
rescue the victim.
o SEIZURES: Administer a benzodiazepine IV; DIAZEPAM
(ADULT: 5 to 10 mg, repeat every 10 to 15 min as
needed. CHILD: 0.2 to 0.5 mg/kg, repeat every 5 min
as needed) or LORAZEPAM (ADULT: 2 to 4 mg; CHILD: 0.05
to 0.1 mg/kg).
1. Consider phenobarbital if seizures recur after diazepam
30 mg (adults) or 10 mg (children > 5 years).
2. Monitor for hypotension, dysrhythmias, respiratory
depression, and need for endotracheal intubation.
Evaluate for hypoglycemia, electrolyte disturbances,
hypoxia.
o HYPOTENSION: Infuse 10 to 20 mL/kg isotonic fluid,
place in Trendelenburg position. If hypotension
persists, administer dopamine (5 to 20 mcg/kg/min) or
norepinephrine (0.1 to 0.2 mcg/kg/min), titrate to
desired response.
o NITRITE THERAPY - Amyl nitrite by inhalation and IV
sodium nitrite (found in cyanide antidote kit) may be
beneficial by forming sulfmethemoglobin, thus removing
sulfide from combination in tissue. Do NOT use sodium
thiosulfate. The antidotal efficacy of nitrite therapy
is controversial; it should be considered in patients
with severe symptoms who present soon after exposure.
o ACUTE LUNG INJURY: Maintain ventilation and oxygenation
and evaluate with frequent arterial blood gas or pulse
oximetry monitoring. Early use of PEEP and mechanical
ventilation may be needed.
DERMAL EXPOSURE
o DECONTAMINATION: Remove contaminated clothing and wash
exposed area thoroughly with soap and water. A
physician may need to examine the area if irritation or
pain persists.
Range of Toxicity:

o At an airborne concentration of 0.05 ppm, hydrogen sulfide
produces a characteristic rotten eggs odor. At 50 to 150
ppm the sense of smell is paralyzed after a short time and
gradually worsening symptoms are noted.
o Exposure to greater than 500 ppm results in severe
toxicity and death. Respiratory paralysis and death may
be noted within 30 to 60 minutes. At 800 to 1000 ppm,
death may be nearly immediate after 1 or more breaths.

[Rumack BH: POISINDEX(R) Information System. Micromedex, Inc., Englewood, CO, 2003; CCIS Volume 116, edition exp May, 2003. Hall AH & Rumack BH (Eds):TOMES(R) Information System. Micromedex, Inc., Englewood, CO, 2003; CCIS Volume 116, edition exp May, 2003.]

CHEMICAL PROPERTIES

Boiling Point:

-60.33 DEG C
[Budavari, S. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Whitehouse Station, NJ: Merck and Co., Inc., 1996. 823]

Melting Point:

-85.49 DEG C
[Budavari, S. (ed.). The Merck Index " ". 823]

Corrosivity:

Anhydrous hydrogen sulfide has low general corrosivity toward carbon steel, aluminum, Inconel, Stellite and 300-series stainless steels at moderate temperatures. Temperatures greater than ca 260 deg C can produce severe sulfidation of carbon steel. Wet hydrogen sulfide can be quite corrosive to carbon steel.
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 281]

Dissociation Constants:

pKa1 = 7.04; pKa2 = 11.96
[Budavari, S. (ed.). The Merck Index " ". 823]

Solubilities:

SOL IN CARBON DISULFIDE
[Weast, R.C. (ed.) Handbook of Chemistry and Physics. 69th ed. Boca Raton, FL: CRC Press Inc., 1988-1989.,p. B-95]

1 G DISSOLVES IN 94.3 ML ABSOLUTE ALCOHOL @ 20 DEG C
[Budavari, S. (ed.). The Merck Index " ". 823]

1 G DISSOLVES IN 48.5 ML ETHER AT 20 DEG C
[Budavari, S. (ed.). The Merck Index " ". 823]

In water, 3980 mg/l at 20 deg C.
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 277]

Soluble in glycerol, gasoline, kerosene, carbon disulfide, crude oil.
[Budavari, S. (ed.). The Merck Index " ". 823]

Soluble in certain polar organic solvents, notably methanol, acetone, propylene carbonate, sulfolane, tributyl phosphate, various glycols, and glycol ethers. N-Methylpyrrolidine dissolves 49 ml/g at 20 deg C at atmospheric pressure.
[Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present.,p. V23 276]

Most of the following safety guidelines for H2S should be effective for preventing HCN exposure as well (except for alerting to the presence of the later) but SWIM is more familiar with H2S than HCN and further study would be required to say for certain.

Standard Preventive Measures:

Contact lenses should not be worn when working with this chemical.
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 170]

EDIT: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

If material /is/ not on fire and not involved in fire: Keep sparks, flames, and other sources of ignition away. Keep material out of water sources and sewers. Attempt to stop leak if without undue personnel hazard. Use water spray to knock down vapors.
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. Washington, DC: Association of American Railroads, Bureau of Explosives, 1994. 586]

Avoid breathing vapors. Keep upwind. ... Do not handle broken packages unless wearing appropriate personal protective equipment. Wash away any material which may have contacted the body with copious amounts of water or soap and water. Approach fire with caution.
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. " ". 586]

Evacuation: If material leaking (not on fire) consider evacuation of one half (1/2) mile. Radius based on amount of material spilled, location and weather conditions.
[Association of American Railroads. Emergency Handling of Hazardous Materials in Surface Transportation. " ". 586]

HYDROGEN SULFIDE SHOULD NEVER BE USED FROM CYLINDER WITHOUT REDUCING PRESSURE THROUGH SUITABLE REGULATOR ATTACHED DIRECTLY TO CYLINDER.
[National Research Council. Prudent Practices for Handling Hazardous Chemicals in Laboratories. Washington, DC: National Academy Press, 1981. 99]

The following is highly recommended:

Personnel using hydrogen sulfide should work in pairs. They should wear for instantaneous use a gas mask with an all purpose canister or a light three minute unit with a self contained air supply, which can be donned quickly before evacuating the area. Operators should carry wet lead acetate paper (turns black in the presence of minute amounts of hydrogen sulfide) on their wrists or belt for detection of dangerous concentrations of gas. In addition, there should be provided multipoint air samplers with alarms for plant production units to constantly monitor the air in and around the units.
[Matheson Gas Products; Matheson Gas Data Book 6th Ed p.409 (1980)]

The following specific precautions should be observed: 1. Do not store reserve stocks of hydrogen sulfide cylinders with cylinders containing oxygen or other highly oxidizing or combustible materials. 2. Ground all lines and equipment used with hydrogen sulfide. 3. Use check valves or traps to prevent suckback into the cylinder. 4. Use a cylinder size which can be conveniently emptied in a reasonably short amount of time. 5. Keep gas masks approved for hydrogen sulfide service in an area not likely to be contaminated, ready for use in case of emergency.
[Matheson Gas Products; " ". p.409 (1980)]

Hydrogen sulfide may readily cause pipes and valves to corrode or become brittle, lines and fittings likely to contain hydrogen sulfide should be inspected frequently and receive special attention, monitoring, and maintenance to prevent leaks.
[NIOSH: Occupational Exposure to Hydrogen Sulfide; p.85 (1977) DHEW (NIOSH) Publication -- 77-158]

EARLY EVALUATION OF PROCESS PLANTS, SUCH AS THE CLAUS TYPE SRU (SULFUR RECOVERY UNIT), IN THE DESIGN STAGE MINIMIZES WORKER EXPOSURE TO TOXIC CHEMICALS. THE CLAUS TYPE SRU CONVERTS THE HYDROGEN SULFIDE IN REFINERY ACID GAS INTO ELEMENTAL SULFUR. THE SRU HANDLES HIGH CONCENTRATIONS OF HYDROGEN SULFIDE, SULFUR DIOXIDE AND OTHER SULFUR COMPOUNDS.
[AMARNAMI SH, POWELL RW; AM IND HYG ASSOC J 43 (1): 49-53 (1982)]

EDIT: Contaminated protective clothing should be segregated in such a manner so that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. Quality assurance to ascertain the completeness of the cleaning procedures should be implemented before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at end of shift, but should remain at employee's place of work for cleaning.

Work clothing that becomes wet should be immediately removed due to its flammability hazard.
[NIOSH. NIOSH Pocket Guide to Chemical Hazards. DHHS (NIOSH) Publication No. 97-140. Washington, D.C. U.S. Government Printing Office, 1997. 170]

MistaMiyagi · Dream Team

Java,

Great ref and scientifically sound -- kudos!

MM

THE MOON RULES --1 · voted for the moon

not to sound stupid but in what reaction is this gas released?

IndoleAmine · Dreamreader Deluxe

This thread is intended to warn people who already know they will have to face the dangers of working with HCN and /or H2S gases.

If you don't know about a reaction that produces HCN and/or H2S, better for you.

We don't want to encourage anyone to perform dangerous syntheses here, but rather want to warn and inform those knowing which chemical(s) they are/will be exposed to.

(besides from that: really good compilation!)

i_a