SECTION I. GENERAL INFORMATION.

Manufactured by: MONTANA SULPHUR & CHEMICAL COMPANY, P.O. Box 31118,

Billings, Montana 59107-1118 (USA). Offices and Plant at 627 Exxon Road,

North East of Billings, Montana.

Emergency Telephone Numbers: Nights/Weekends/Holidays (406) 252-7101; or Business Hours (406) 252-9324. {Let ring till Operator answers - Do NOT hang up.}

Non-Emergency: (406) 252-9324; FAX (406) 252-8250; E-Mail mscc@imt.net

Chemical Name: HYDROGEN SULFIDE Trade Name: HYDROGEN SULFIDE

Formula: H₂S CAS #: [7783-06-4] Common Names: H₂S, Sewer Gas, Sulfuretted Hydrogen,

UN #: 1053;

US DOC Schedule B No.: 2813.90.6000 49 Series STC Code: 49 054 10

CAA Section 302, EHS Threshold Planning Quantity (TPQ) 500 pounds

CAA Section 112(r) Threshold Quantity (TQ) 10,000 pounds

RCRA Code = U135; RQ=100 pounds

HYDROGEN SULFIDE, purity 99.25% minimum

Typical impurities: propylene, propane, carbon dioxide, nitrogen, methane, ethane, water, all less than 1%. May contain carbonyl sulfide, carbon disulfide, and/or mercaptans all less than 1%.

Exposure Limits: OSHA* ACC: 20 ppm (30 mg/m3) with Acceptable Maximum Peak above ACC of 50 ppm (75 mg/m3) 10 minute/day if no other measurable exposure occurs. ACGIH TLV-TWA 10 ppm; TLV-STEL 15 ppm (15 minutes, not more than 4 times per 8 hr day. NIOSH recommendation: C=10 ppm, [10 minutes]. Manufacturer's Recommendation to avoid eye irritation 10 ppm, avg. NIOSH IDLH [30 minutes]=100 ppm, {NOTE: IDLH is not working level; it is deemed a concentration from which escape may be made in 30 minutes without injury or irreversible health effects and without deleterious / severe impediment to escape--e.g. irritation.}.

Since combustion of hydrogen sulfide in air produces water vapor and sulfur dioxide (SO₂) mixed with large volumes of nitrogen the exposure limits for SO₂ are shown here for information purposes only: Sulfur Dioxide -OSHA*=5 ppm TWA (13 mg/m3). ACGIH TLV=2 ppm; STEL=5 ppm; NIOSH TWA=2 ppm. NIOSH IDLH=100 ppm. See above for explanation of IDLH.

* OSHA adopted ACGIH STEL/TWA levels effective 3/1/89, but has withdraw that action. See 1910.1000 for permissible methods of compliance.

[Abbreviations Key: mg/m3 designates milligrams per cubic meter; ppm designates parts per million (volume). ACC designates Acceptable Ceiling Concentration; TWA designates Time Weighted Average, STEL designate Short Term Exposure Limit; TLV designates Threshold Limit Value. IDLH designates Immediately Dangerous to Life/Health.]

SECTION III. PHYSICAL DATA

Boiling point at one atmosphere pressure is -76.4 F.

Specific Gravity of liquid at 60 F is 0.79.

Vapor Pressure at 60 F is 229 PSIA.

Vapor Density (air=1) is 1.17. [slightly heavier than air]

Solubility in water at 68 F/1 atm. is 3.8 grams/liter.

Percent Volatile by volume is 100%.

Odor:-Strong "rotten eggs" at low concentrations (as low as 0.02 -- 0.03ppm) changing to "sickening sweet odor" as levels rise above about 50-200 ppm; exposure above 100 ppm may rapidly deaden the sense of smell [reportedly in as little as 2 - 15 minutes], particularly at higher concentrations. Above 200 ppm loss of smell is very rapid. Olfactory fatigue may also, reportedly, result from prolonged exposure to levels below 100 ppm. We have not observed this latter effect in normal outdoor operations and the normally associated chronic intermittent exposures resulting from handling routine small leakages from CLOSED systems. Users should beware however that in enclosed spaces, buildings etc. where concentrations may be relatively constant, olfactory acclimatization or fatigue will occur and rising concentrations may not be noticed in such cases.

Hydrogen Sulfide is a liquified, compressed gas, stored and transported under its own vapor pressure. Warning: Pressure may propel objects long distances with considerable force.

Auto-Ignition Point (air):~ 500 F. Flammable Limits: LEL 4.3% v/v UEL 46% v/v Flash Point: Not Applicable. NFPA Hazard Ratings: Health 3, Flammability 4, Reactivity 0.

Combustible mixtures with air can exist at all ambient temperatures. Gas is extremely flammable. `Vapors of a FLAMMABLE GAS may travel to a source of ignition and flashback.

Compressed Liquified Gas Hazard: This product is shipped under high pressure in specially constructed pressure vessels. The maximum rated working pressure of our hydrogen sulfide tank cars is 400 PSIG. The maximum working pressure of our hydrogen sulfide tank trailers is 500 PSIG. We recommend maintaining tank pressures no higher than 50 PSIG below rated working pressures. Pressure relief valves may eject gas at high velocity. Protect these vessels from all hazards that may damage their structural integrity or cause leakage or rupture, such as, high temperatures, nearby fires, impacts, vandalism, abuse, corrosives, etc. Similar consideration must be given to other equipment containing high pressure hydrogen sulfide.

Extinguishing media: 1. Shut off supply of hydrogen sulfide gas. 2. Use water fog or C02 to control fire to gain access to controls. Wear breathing protection appropriate to potential concentrations: Best choice is positive pressure self-contained or airline respirator.

Special Fire Fighting Procedure: Notify manufacturer/shipper immediately. DO NOT ATTEMPT TO EXTINGUISH FIRE UNLESS THE SOURCE OF LEAKING GAS CAN BE SHUT OFF. To do so will create a more serious hazard of potentially poisonous and/or flammable concentrations of gas spreading out at ground level. Air that was 'safe' with the fire, may suddenly become rich in H₂S. The fire will greatly reduce the level of toxicity and aid in dispersion of the gas to harmless levels. KEEP TANKS AND EQUIPMENT COOL WITH WATER SPRAYS (to reduce rate of leak and prevent Rupture). STAY UPWIND OF LEAK OR FIRE absent full respiratory protection. WEAR SELF CONTAINED (or suitably equipped airline) PRESSURE-DEMAND TYPE BREATHING APPARATUS. Keep unnecessary persons away at least 500 yards until hazard is evaluated. With a large fire, irritating levels of sulfur dioxide gas may sometimes exist downwind. Nevertheless this is preferable to a large and unignited leak for the reasons above. Evacuate area downwind of leak/fire if necessary or where odor (rotten eggs or burning matches) is noticed. In very large fires impinging on tanks, rupture may occur if tank not kept cooled during fires.( This phenomenon -- notorious with LPG tanks-- is called "BLEVE"). Keep clear of tank ends. US DOT recommended BLEVE hazard evacuation/isolation area is 0.5 miles.

Exposure Limits: See Section II. The current NIOSH criteria document recommends exposure be limited to 10 ppm for ten minutes, based on potential for EYE IRRITATION in some individuals.

The primary routes of entry to be addressed are INHALATION and EYE EXPOSURE. Frostbite may occur on CONTACT with escaping liquid hydrogen sulfide or equipment containing evaporating liquid. See Section VIII.

Effects of overexposure: Deadening of sense of smell, headache, eye and breathing passage irritation or pain, dizziness, coughing, loss of consciousness, respiratory paralysis, coma, death. Target Organs are the Eyes and Airway (respiratory) Membranes (irritation) and the Nervous System (olfaction, dizziness, unconsciousness, interference with respiratory centers resulting in stopped breathing, gastrointestinal effects, etc.). Other effects have appeared in the literature associated with this gas (generally involving exposures to mixtures of hydrogen sulfide and other toxics). These effects include fatigue, irritability, incoordination, nausea, vomiting, chemical pneumonia, edema, hyperpnea, low blood pressure, convulsions, hematuria, loss of appetite, sleep disturbance, conjunctivitis, excitement, sensation of dryness or pain in eye, nose, throat, chest, etc. Contact with liquid may cause frostbite.

No reports associating hydrogen sulfide in air with carcinogenesis, mutagenesis, or teratogenesis were found in the literature.

Hydrogen sulfide is known to occur naturally in the human body at low levels and is safely metabolized and eliminated at such levels.

Emergency and First Aid Procedures:

DO NOT ENTER AN ACTIVE LEAK AREA WITHOUT PROPER RESPIRATORY PROTECTION FOR YOURSELF (FRESH AIR MASK) EVEN TO ATTEMPT A RESCUE! Without such protection you run a great risk of being overcome by gas yourself, which will only compound the rescue problem.

Inhalation: Keep calm. Get exposed person to fresh air immediately, without endangering yourself. If victim's breathing has stopped, clear airway, give mouth-to-mouth resuscitation immediately and continue until breathing is restored. Use CPR if pulse is missing. If breathing is difficult, offer/administer oxygen. If more than one victim is involved, enlist the aid of others. Do not delay or cease administration of resuscitation to any victim whose breathing/pulse has stopped as seconds are important. After natural breathing is restored, treat as for shock; keep patient warm and quiet. Reassure victim -- recovery is normally rapid and complete if breathing is restored promptly. As soon as practical seek medical aid/advice.

Skin and eyes: If irritation occurs, flush eyes and/or body with cool, clean water 15 minutes. Remove contaminated clothing. Unless irritation is obviously minor, seek medical attention.

Frostbite: Remove from contact; do NOT rub or overheat; warm exposed part gradually using body heat, cool to luke warm water; keep patient warm; seek medical advice.

Medical/Industrial Hygienist Notes for consideration by health professionals. Not offered as medical advice: Consideration should be given to limiting exposures mixed with other toxic materials such as ethanol, carbon disulfide as additive effects may occur and are suggested in the literature. Use of CNS depressants (alcohol, drugs) on shift or prior to work should be discouraged for this reason. Skin absorption upon exposure to extremely high concentrations (e.g. 100% gas) has been demonstrated in the laboratory on shaved animals, however, no evidence exists to suggest that skin exposure alone to hydrogen sulfide in man is a significant route of entry even at the exposure concentrations and durations encountered in handling large leaks out-of-doors. Such leaks have been routinely/safely handled without chemical suits and in ordinary work clothes and gloves. Prudence suggests that skin exposure should be minimized by working up wind of leaks to the extent practical. Respiratory and eye protection are required, however. Since material is normally rejected by the body, sucessful post-acute over-exposure treatment is generally conservative: brief observation, oxygen if desired. Patient recovering from unconsciousness may report fatigue, headache, 'flu-like' symptoms which may be treated accordingly to alleviate. Since chemical pneumonia has been reported associated with this compound, on occasion, patient may be advised to report pneumonia-like symptoms. Literature reports compound is "thought to inhibit cytochrome oxidase system" by interference with use of oxygen by that system. Amyl nitrate has been reportedly used as possible treatment of severe poisoning (Eli Lilly, developer), but that treatment is "controversial...not always effective and can have serious side effects." Pyruvate, an intermediate in normal carbohydrate metabolism, has reportedly shown promise in protecting experimental mice injected with otherwise lethal doses of sodium sulfide. {A.S. Hume, U. of Mississippi Medical Ctr., Jackson, MS. See Chemical Week, 1/27/88, p 44.)

Hydrogen sulfide (pure) is stable at normal ambient temperatures. At high temperatures the gas dissociates into hydrogen and sulfur vapor. Flammable and Explosive mixtures with air should be avoided. Avoid unintentional exposure to all oxidizing agents including air. Examples of common oxidizing agents are PERCHLORATES, NITRATES, CHLORATES, PERMANGANATES, PEROXIDES, OXYGEN, HALOGENS, etc. The compound reacts with most metals, including iron, to form sulfides. In some cases the sulfide coating, if left intact, retards or stops further reaction, effectively protecting the metal. It reacts vigorously with alkaline materials and solutions. Corrosive mixtures can form if air and water are present. Water solutions are weakly acidic. Sulfide stress cracking and hydrogen embrittlement can occur under some conditions, and allowance for same should be made in design. These phenomena are more likely are higher temperatures and high stress levels. Sulfides of iron will oxidize fairly rapidly in moist air. In the presence of other readily oxidized combustibles (such as some oily materials) under certain conditions, the heat liberated from this oxidation is sufficient to result in spontaneous ignition. This phenomenon has not been observed by this company with the pure gas in contact with unprotected steel at ordinary temperatures, however. Users are cautioned against allowing inadvertent mixtures of iron sulfides and miscellaneous oils to remain. Oxidation is accelerated by higher temperatures. Heat buildup and ignition can be prevented by keeping the sulfides wet until oxidation is complete.` Dry pure hydrogen sulfide can be handled in suitable carbon steel piping and vessels. Wet or impure hydrogen sulfide should be handled only in equipment carefully selected to allow for or resist these corrosion effects. Carbon or stainless steels may be suitable in some applications. Hydrogen sulfide attacks rubber, copper, lead, silver and mercury, although some alloys containing these materials are satisfactory. Generally, the corrosivity of hydrogen sulfide is low in the pure state but increased by the presence of moisture, air, or thermal/mechanical stress in common materials of construction. Hazardous polymerization of pure H2S is not known to occur.

SECTION VII. SPECIAL LEAK PROCEDURES AND WASTE DISPOSAL

WORK IN BUDDY SYSTEM. APPROACH WITH CAUTION. WEAR RESPIRATORY PROTECTION unless concentrations are known to be minimal.

Shut off the source of the leaking gas. Isolate the leak from large reservoirs of liquid or gas such as delivery vehicles, storage tanks, etc. Notify this company immediately for assistance. If the leak cannot be stopped by closing valves or tightening plugs or flange bolts, it may be possible to transfer the material to flare or to another vessel. The magnitude of any leak can be greatly diminished by removing vapor from the leaking vessel and flaring it or disposing of it by other safe means as quickly as practical. If the vessel is movable, it is advisable to move it to an isolated area.

If the leak is extremely large and poses an imminent hazard to the public and cannot be quickly stopped by any of the above means, then the proper action is to immediately set fire to the leaking material by any means available -- flare guns, fusees, thrown torches, etc., taking care to stay well upwind and out of the flash fire that may occur upon ignition. Keep the tank as cool as possible with water sprays, and vent vapors to flare if possible. Do not breathe the combustion products which will contain sulfur dioxide. Do not attempt to extinguish the fire. Keep people away from the tank and especially the downwind area until all of the gas is consumed by fire and dissipated. Consider the possibility of "BLEVE" and take appropriate action if needed. (See Section IV above).

Waste Disposal: Depending on local conditions, routine waste as may be safely disposed of to process, or by flaring, incineration or absorption in caustic solutions. This should be done in accordance with laws and regulations. Emergency Ignition of large leaks converts hydrogen sulfide to sulfur dioxide and water vapor mixed with tremendous diluting quantities of nitrogen and air. The heat liberated is substantial and lifts the combustion products high into the air and generally safely away from people. Notify shipper of any unintentional discharges of gas to atmosphere.

TRAINING in the properties and proper handling of this material is your best safety investment. Practice use of fresh air masks frequently. Do not allow untrained personnel to work unsupervised in hydrogen sulfide work areas.

When working with real or suspected leaks, wear approved full face fresh air masks with positive pressure in the mask, such as Survivair Models 9038 or 9838 (Bureau of Mines Approval BN-13E-24) or equivalent.

Protect skin from exposure to cold pipes & liquid and gas. (Gloves, long sleeves, long pants). Dress for the weather but avoid clothing which unduly restricts motion or ability to escape. See Section V.

Ventilation: For maximum safety - avoid use or storage indoors. Indoor areas should have positive ventilation with at least 10 air changes per hour. Use of a fume hood in laboratories is advisable. Automatic monitoring equipment is advisable in indoor applications. Isolated outdoor areas provide maximum handling safety. Natural ventilation helps to rapidly dissipate leaks.

Detection Equipment: Portable chemical detectors should be available to workers. These can be of the "detector tube" variety [Draeger; GasTech etc.] or the electronic variety. This company's experience indicates a greater reliability of the non-electronic types in actual field use. Leak location is assisted with lead acetate tape and soap solutions which should also be available. Automatic monitors may also be used, but, are of very limited value in detecting leaks outdoors. Workers should be advised NOT to depend entirely on automatic monitors, if used, to determine safety of a suspected leak area. Monitor responses can be slow and erratic producing both false negative and false positive readings in a typical environment. Consideration must be given to the risk of introducing a false sense of security in workers depending on automatic monitors. The company considers automatic monitors useful if gas must be handled indoors and there is a potential for gradual buildup of concentrations.

Small leaks may be effectively pinpointed with the use of soapy water solutions, commercial preparations ("SNOOP"), lead acetate tape.

Work in the buddy system whenever working with a known or suspected leak and whenever a release of material to the air is probable (sampling, hookup, disconnect, "on line maintenance," operations etc.). Wear proper protective equipment including positive pressure or tightly sealed pressure demand type, full face air masks in handling leaks or probable leaks. Keep unneeded personnel away from the area of hazardous concentrations of gas.

Storage and Handling. Store and handle this material in suitable pressure tight equipment, preferably located outdoors for maximum safety. If possible, locate storage away from large numbers of people and from other equipment and materials which might involve the storage vessels in a fire. Be sure that equipment is adequately protected against physical damage, unauthorized access, excessive pressure, and temperature, and that pressure relief devices vent only to areas where persons cannot be exposed or, preferably to a suitable disposal system or flare. Prevent the unintentional ignition of the gas by controlling or eliminating sources of ignition such as sparks, smoking materials, and open lights in the area. Remember, however, that one of the best control methods in handling leaks large enough to burn is to ignite them. Therefore have means of ignition at hand. Adequate water and hoses should be nearby in case of fire. Cylinders of this material are recommended to be stored in a cool, preferably dry location, with good natural ventilation. A roofed area without walls would be an example. Do not store near oxidizing materials, acids or other corrosive materials. Do not overfill vessels or containers. A sealed liquid full container can overpressure and rupture or leak upon even mild heating due to hydraulic expansion. For transportation filling limits consult CFR 49, and DOT Exemption(s).

Unloading Trailers and Tank Cars: Authorized and trained personnel only. Before receiving this material consult with manufacturer and refer to manufacturer's Customer Information Booklet in developing safe procedures and systems for unloading. Block wheels, protect from collision, make positive ground connection. Work in buddy system. Fresh air masks advised. All transport valves must be closed before removing flanges. Check piping for leaks before opening transport valves. Open valves very slowly to prevent closing of transport excess flow valves. Introduce no foreign material, including water and air, into transports. Use heating coils, if any, only in accordance with shipper's instructions and safe procedures. Prevent overpressure and "backflow" during unloading. Monitor pressure and temperature of vessel frequently during unloading. Remotely controlled valves on unloading lines can be useful in shutting down unloading during routine processing and during potential emergencies. When unloading is complete, close valves to transport and system, depressure or otherwise clear hazardous quantities of product from line segment to be broken, and carefully disconnect, using same precautions as with a full tank. Apply all closures, plugs, and covers properly and see that placards, labels, and warnings are properly applied. Check your work thoroughly for leaks! Sign DOT certification on shipping release paper, and notify shipper of release and routing.

Maintenance precautions: Use COMMON SENSE and be thoroughly familiar with your safety equipment and the properties of this material and the information provided. Vessel Entry: Purge thoroughly and test for oxygen and hydrogen sulfide before entry into process vessels, enclosed spaces, trenches, which may have contained this gas. Where applicable, steaming followed by forced airing is most readily effective to drive residual material from vessels (however other methods can be effective). Before purge and entry, isolate vessels completely and positively from other process lines and equipment (line blinds/disconnection/ locked double block & bleed). Keep workers inside vessels and enclosed spaces under surveillance and have rescue equipment at hand. Personnel inside vessels should not use cleaning agents likely to react with sulfide residues (acids for example) releasing hydrogen sulfide. Dissolved sulfide in liquids such as water, alcohol, oils or sludge may be released by warming. Retest air in vessels frequently and whenever vessel temperature rises (as from sunlight or space heating). Keep sulfide residues moist until fully oxidized or cleaned out (See Reactivity). Welding/Cutting/Grinding: Before performing spark-generating activities in a hydrogen sulfide work area, check for possible sources of flammable gas. Do not perform hot-work on piping/vessels which contain explosive mixtures of the gas and air or other oxidizers. "Hot-Tapping" containers / piping containing the pure gas can be done safely, however consideration must be given to compromising the integrity of the vessel during the weld. (See reactivity section.) Whenever practical, reduce pressure to a minimum prior to hot-tap, and submerge the inside of the work in water or other non-reactive fluid. Stress relieving (post weld heat treatment), especially on vessels, is believed to reduce the probability of sulfide stress cracking in carbon steel vessels. Some firms also recommend stress relief of welds on piping systems, particularly highly stressed systems. Experience here indicates, however, that typical systems of small pipe, operating with pure gas, and properly welded and tested, operate with extremely high reliability without such treatment. This is believed due to the very low ratio of actual stress relative to bursting stress which we require. Welding and cutting on pipe containing or coated with sulfide residues may release sulfur dioxide gas in addition to welding fumes. Avoid inhaling fumes. Use adequate ventilation. Other R&M work on H2S systems: "Hot-work" or R&M on systems which have not been positively purged and isolated (as with line blinds) must be treated as potentially contaminated or potential leak sources. A closed valve is NOT sufficient to "isolate" a line -- valves leak! Work in buddy system and with respiratory protection in such situations, as if a real leak were present.

NOTICE: The information and judgments contained herein are based on experience and/or data considered accurate, however, no warranty is expressed or implied regarding accuracy or the results to be obtained from use. Vendor assumes no responsibility for injury to vendee or third person proximately caused by the material. Additionally, vendor assumes no responsibility for injury to vendee or third persons proximately caused by abnormal use of the material even if normal safety procedures are followed. Furthermore, vendee absolutely assumes full responsibility for the risks in his use of the material.