Difference between revisions of "Naphtha" - New World Encyclopedia

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:''Not to be confused with'' [[Naphthalene]].
 
:''Not to be confused with'' [[Naphthalene]].
 
[[Image:Camp fuel.jpg|thumb|300px|right|Coleman camp fuel, also known as [[white gas]], is a common naphtha fuel used in many lanterns and torches.]]
 
[[Image:Camp fuel.jpg|thumb|300px|right|Coleman camp fuel, also known as [[white gas]], is a common naphtha fuel used in many lanterns and torches.]]
  
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'''Naphtha''' is a name given to several mixtures of liquid [[hydrocarbon]]s that are extremely volatile and flammable. Naphtha is generally obtained during the [[distillation]] of [[petroleum]] or [[coal tar]], and occasionally by the distillation of wood. Accordingly, it is known by different names, such as petroleum naphtha, coal-tar naphtha, or wood naphtha.
+
'''Naphtha''' is a name given to several mixtures of liquid [[hydrocarbon]]s that are extremely volatile and flammable. Each such mixture is obtained during the [[distillation]] of [[petroleum]] or [[coal tar]], and occasionally by the distillation of wood. Accordingly, it is known by different names, such as petroleum naphtha, coal-tar naphtha, or wood naphtha.
−
 
+
{{toc}}
 
Naphtha is used primarily as [[feedstock]] for producing a high-[[Octane rating|octane]] [[gasoline]] component via the [[catalytic reforming]] process. It is also used in the [[petrochemical]] industry for producing [[olefin]]s in [[steam crackers]] and in the chemical industry for [[solvent]] (cleaning) applications.
 
Naphtha is used primarily as [[feedstock]] for producing a high-[[Octane rating|octane]] [[gasoline]] component via the [[catalytic reforming]] process. It is also used in the [[petrochemical]] industry for producing [[olefin]]s in [[steam crackers]] and in the chemical industry for [[solvent]] (cleaning) applications.
  
−
== Alternative names ==
+
==Etymology==
  
−
Naphtha is known by various names, including ligroin, VM&P Naphtha (Varnish Makers and Painter's Naphtha<ref>[http://www.brown.edu/Administration/EHS/resources/NPG/npgd0664.htm]</ref>), Benzin, Petroleum Naphtha, Naphtha ASTM, Petroleum Spirits, white spirit,<ref>In the UK, "white spirit" is something different entirely.</ref> shellite, and ronsonol.
+
The origin of the word ''naphtha'' is unclear. It was an ancient Greek word that referred to any type of [[petroleum]] or [[Pitch (resin)|pitch]]. The Greeks themselves borrowed the word from the [[Old Persian]] words ''nafata,'' ''naft,'' or ''neft,'' which were used to describe bubbling oil. Naphtha may also have been derived from the name of the [[Veda|Vedic]] [[Hindu]] god [[Apam Napat]], the god of freshwater, sometimes described as a fire god.
  
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== Physical properties ==
+
== Alternative names ==
−
 
 
−
Naphthas have a molecular weight range of 100-215, a specific gravity range of 0.75-0.85, and a boiling point range of 70-430 &deg;F. Their vapor pressure is generally less than 5 mm mercury. Naphthas are insoluble in water. They are colorless (with a kerosene odor) or red-brown (with an aromatic odor). They are incompatible with strong oxidizers.<ref>CAS No.: [http://www.cdc.gov/niosh/npg/npgd0664.html 8032-32-4], [http://www.cdc.gov/niosh/npg/npgd0438.html 8030-30-6], [http://www.cdc.gov/niosh/npg/npgd0492.html 8002-05-9].</ref>
 
−
 
 
−
== Health and safety considerations ==
 
−
 
 
−
Forms of naphtha may be [[carcinogen]]ic, and frequently products sold as naphtha contain some impurities that may have deleterious properties of their own.<ref>[http://nafaa.pbwiki.com/Naphtha] [http://monographs.iarc.fr/ENG/Monographs/vol47/volume47.pdf]</ref> Like many [[hydrocarbon]] products, because they are products of a [[refractory]] process where a complex soup of chemicals is broken into another range of chemicals, which are then graded and isolated mainly by their [[specific gravity]] and [[Volatility (chemistry)|volatility]], there is a range of distinct chemicals included in each product. This makes rigorous comparisons and identification of specific carcinogens difficult, especially in our modern environment where exposure to a great number of such products occurs on a daily basis, and is further complicated by exposure to a significant range of other known and potential carcinogens.<ref>For instance, see [http://www.defence.gov.au/dpe/dhs/research/shoamp/Mortality_Final_report_Sept_2003.pdf].</ref>
 
−
 
 
−
Below are linked some Material Safety Data Sheet (MSDS) specifications for different "naphtha" products, which contain varying degrees of naphtha, as well as various other chemicals. As well as giving health guidelines, these are one of the few ways to determine what a given product contains.
 
−
 
 
−
* JT Baker VM&P Naphtha [http://www.jtbaker.com/msds/englishhtml/p1696.htm MSDS].
 
  
−
* Diggers Shellite [http://www.diggersaust.com.au/files/Shellite.pdf MSDS]
+
Naphtha is known by various names, depending on its source, composition, uses, and manufacturing company. Some names include ligroin, VM&P Naphtha (Varnish Makers and Painter's Naphtha,<ref>[http://www.brown.edu/Administration/EHS/resources/NPG/npgd0664.htm "NIOSH Pocket Guide to Chemical Hazards": VM & P Naphtha] Retrieved August 19, 2007.</ref> Benzin, petroleum naphtha, petroleum spirits, and naphtha ASTM. Another name is ''shellite'' ([[Australia]])—also known as ''white gas'' ([[North America]]), ''white spirit,'' or ''[[Coleman Company|Coleman]] fuel''—which is a white liquid with a hydrocarbon odor. Given its high flammability and low [[flashpoint]] (less than -30 &deg;C), it is used in many low-pressure camping stoves. ''Ronsonol'' is a brand name used in North America and is marketed as a refill fluid for [[cigarette lighter]]s.
  
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* Shell Ronsonol MSDS [http://www.cooperbooth.com/datasheets/160606.pdf source1] [http://pages.slc.edu/~aschultz/chemical_hygiene/MSDS/theater%20msds/LIGHTER%20FLUID.PDF source2]
+
== Properties ==
  
−
* Links to [http://www.nafaa.org/msds.html more MSDS] for various camping-stove fuels including several that include naphtha
+
To obtain the product known as ''naphtha,'' a complex soup of chemicals is broken into another range of chemicals, which are then graded and isolated mainly by their [[specific gravity]] and [[Volatility (chemistry)|volatility]]. As a result, the product contains a range of distinct chemicals with a range of properties. They generally have a molecular weight range of 100-215, a specific gravity range of 0.75-0.85, and a boiling point range of 70-430 &deg;F. Their vapor pressure is usually less than 5 mm mercury.
  
−
[[Benzene]] in particular is a known high-risk carcinogen, and so benzene content is typically specified in the MSDS. But more specific breakdown of particular forms of hydrocarbon is not as common.
+
Naphthas are insoluble in water. They are colorless (with a kerosene odor) or red-brown (with an aromatic odor). They are incompatible with strong oxidizers.<ref>NIOSH CAS No.: [http://www.cdc.gov/niosh/npg/npgd0664.html 8032-32-4], NIOSH "Pocket Guide to Chemical Hazards" [http://www.cdc.gov/niosh/npg/npgd0438.html 8030-30-6], (September 2005)[http://www.cdc.gov/niosh/npg/npgd0492.html 8002-05-9]Retrieved October 12, 2007. </ref>
  
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===Properties of Naphthas===
+
Generally speaking, less dense naphthas ("light naphthas") have a higher [[paraffin]] content. They are therefore also called '''paraffinic naphtha'''. The denser naphthas ("heavy naphthas") are usually richer in naphthenes and aromatics, and they are therefore referred to as N&A's.
−
 
 
−
**Health Hazards
 
−
“Light naphtha, a mixture consisting mainly of straight-chained and cyclic aliphatic hydrocarbons having from five to nine carbon atoms per molecule. Heavy naphtha, a mixture consisting mainly of straight-chained and cyclic aliphatic hydrocarbons having from seven to nine carbons per molecule.”<ref>E. Meyer, ''Chemistry of Hazardous Materials'' 3rd ed. (Prentice Hall, 1998), page 458.</ref> “Almost all volatile, lipid-soluble organic chemicals cause general, nonspecific depression of the central nervous system or general anesthesia.”<ref>J. LaDou, ''Occupational and Environmental Medicine'', 3rd ed. (Lange Medical Books, McGraw Hill, 2004), page 508.</ref> The OSHA PEL TWA = 100 parts-per-million (ppm); Health Hazards/Target Organs = eyes, skin, RS, CNS, liver kidney. Symptoms of acute exposure are dizziness and narcosis with loss of consciousness. The World Health Organization categorizes health effects into three groups: reversible symptoms (Type 1), mild chronic encephalopathy (Type 2) and severe chronic toxic encephalopathy (Type 3).
 
  
 
== Production of naphtha in refineries and uses==
 
== Production of naphtha in refineries and uses==
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** [[Aromatic]]s content (volume percent)
 
** [[Aromatic]]s content (volume percent)
  
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=== Paraffinic naphthas ===  
+
=== Paraffinic (or light) naphthas ===  
  
−
Generally speaking, less dense ("lighter") naphthas will have a higher [[paraffin]] content.  These are therefore also referred to as '''paraffinic naphtha'''. The main application for these naphthas is as a [[feedstock]] in the petrochemical production of [[olefin]]s. This is also the reason they are sometimes referred to as "light distillate feedstock" or '''LDF''' (these naphtha types can also be called "straight run gasoline"/'''SRG''' or "light virgin naphtha"/'''LVN''').  
+
The main application for paraffinic ("light") naphthas is as [[feedstock]] in the petrochemical production of [[olefin]]s. This is also the reason they are sometimes referred to as "light distillate feedstock" or '''LDF'''. (These naphtha types may also be called "straight run gasoline" (SRG) or "light virgin naphtha" (LVN).)
  
−
When used as feedstock in petrochemical steam crackers, the naphtha is heated in the presence of water vapour and the absence of oxygen or air until the hydrocarbon molecules fall apart. The primary products of the cracking process are olefins ([[ethylene]] / [[ethene]], [[propylene]] / [[propene]] and [[butadiene]]) and aromatics ([[benzene]] and [[toluene]]). These are used as feedstocks for derivative units that produce [[plastic]]s ([[polyethylene]] and [[polypropylene]] for example), [[synthetic fiber]] precursors ([[acrylonitrile]]), industrial chemicals ([[glycol]]s for instance).
+
When used as feedstock in petrochemical steam crackers, the naphtha is heated in the presence of water vapor and the absence of oxygen or air until the hydrocarbon molecules fall apart. The primary products of the cracking process are olefins ([[ethylene]] / [[ethene]], [[propylene]] / [[propene]] and [[butadiene]]) and aromatics ([[benzene]] and [[toluene]]). These are used as feedstocks for derivative units that produce [[plastic]]s ([[polyethylene]] and [[polypropylene]], for example), [[synthetic fiber]] precursors ([[acrylonitrile]]), and industrial chemicals ([[glycol]]s, for instance).
  
 
=== Heavy naphthas ===
 
=== Heavy naphthas ===
  
−
The "heavier" or rather denser types are usually richer in naphthenes and aromatics and therefore also referred to as N&A's. These can also be used in the petrochemical industry but more often are used as a feedstock for refinery catalytic reformers where they convert the lower [[octane rating|octane]] naphtha to a higher octane product called [[reformate]]. Alternative names for these types are Straight Run Benzene (SRB) or Heavy Virgin Naphtha (HVN).
+
The "heavy" naphthas can also be used in the petrochemical industry, but they are more often used as feedstock for refinery catalytic reformers where they convert the lower [[octane rating|octane]] naphtha to a higher octane product called [[reformate]]. Alternative names for these types are "straight run benzene" (SRB) or "heavy virgin naphtha" (HVN).
  
−
=== Other applications / descriptions ===
+
=== Additional applications ===
  
−
Naphthas are also used in other applications such as:
+
Naphthas are also used in other applications, such as:
−
* (as an unprocessed component - in contrast to reforming above) in the production of [[petrol]]/[[gasoline|motor gasoline]].
+
* in the production of [[gasoline]].
−
* industrial [[solvents]] and cleaning fluids
+
* in industrial [[solvents]] and cleaning fluids
 
* an oil painting medium
 
* an oil painting medium
 
* the sole ingredient in the home cleaning fluid [[Energine]], which has been discontinued. You can purchase this type of naphtha at any hardware store.
 
* the sole ingredient in the home cleaning fluid [[Energine]], which has been discontinued. You can purchase this type of naphtha at any hardware store.
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* a fuel for [[fire spinning]], fire [[juggling]], or other fire performance equipment which creates a brighter and cleaner yet shorter burn.
 
* a fuel for [[fire spinning]], fire [[juggling]], or other fire performance equipment which creates a brighter and cleaner yet shorter burn.
 
* to lightly wear the finish off [[guitar]]s when preparing "relic" instruments.
 
* to lightly wear the finish off [[guitar]]s when preparing "relic" instruments.
−
* to remove oil from the [[diaphragm_(optics)|aperture blades]] of [[Photographic_lens|camera lenses]], which if present can cause slow the movement of the blades, leading to [[Exposure_(photography)|overexposure]].
+
* to remove oil from the [[diaphragm_(optics)|aperture blades]] of [[Photographic_lens|camera lenses]], which if present can slow the movement of the blades, leading to [[Exposure_(photography)|overexposure]].
  
−
==Examples==
+
== Health and safety considerations ==
−
''Shellite'' ([[Australia]]), also known as ''white gas'' ([[North America]]), ''white spirit'' or ''[[Coleman Company|Coleman]] fuel'', is a water white liquid with a hydrocarbon odour.  Shellite has a [[flashpoint]] less than -30 degrees [[Celsius]], and a [[boiling point]] of 47 degrees Celsius.  The composition of shellite is 95% [[paraffin]]s and naphthenes, less than 5% aromatic hydrocarbons and less than 0.5% [[benzene]].  It is highly flammable and due to its low flashpoint is used in many low pressure camping stoves.  Shellite is also a fast drying solvent used for cleaning metal, hard plastic and painted surfaces.
 
−
''Ronsonol'' is a brand name used in North America, and is marketed principally as a refill fluid for [[cigarette lighter]]s.
 
  
−
==Etymology==
+
Forms of naphtha may be [[carcinogen]]ic, and products sold as naphtha frequently contain some impurities that may have deleterious properties of their own.<ref>[http://monographs.iarc.fr/ENG/Monographs/vol47/volume47.pdf Report of the International Agency for Research on Cancer.] Retrieved August 19, 2007.</ref> Given that the term ''naphtha'' is applied to different products, each containing a variety of distinct chemicals, it is difficult to make rigorous comparisons and to identify specific carcinogens. This task is further complicated by the presence of a number of other known and potential carcinogens in modern environments.<ref>For instance, see [http://www.defence.gov.au/dpe/dhs/research/shoamp/Mortality_Final_report_Sept_2003.pdf Study of Health Outcomes in Aircraft Maintenance Personnel.] Retrieved August 19, 2007.</ref>
−
The origin of the word '''Naphtha''' is unclear. It is an Ancient Greek word which was used to refer to any sort of [[petroleum]] or [[Pitch (resin)|pitch]]. The Greeks themselves borrowed the word from the [[Old Persian]] words ''nafata'', ''naft'' or ''neft'', which were used to describe bubbling oil. Naphtha may also have been derived from the name of the [[Veda|Vedic]] [[Hindu]] and [[Avesta|Avestic]] god [[Apam Napat]], a form of [[Agni]], or fire god.
 
  
−
Naphtha is the root of the words [[naphthalene]] and [[napalm]], which is derived from naphtha by mixing under controlled conditions with aluminium salts of palmitic acid (a type of soap).
+
Below are links to some Material Safety Data Sheet (MSDS) specifications for different "naphtha" products, which contain varying proportions of naphtha and other chemicals. Besides giving health guidelines, they provide one of the few ways to determine what a given product contains.
  
−
==Air Sampling for Naphthas==
+
* Petroleum Ether MSDS<ref>[http://www.jtbaker.com/msds/englishhtml/p1696.htm Mallinckrodt Baker, Petroleum Ether MSDS]. Retrieved August 19, 2007. </ref>
  
−
Air sampling is conducted to identify and evaluate employee or source exposures of potentially hazardous gas, vapor or particulates; assess compliance; and evaluate process or reformulation changes.
+
* Diggers Australia Shellite<ref>[http://www.diggersaust.com.au/files/Shellite.pdf Diggers Australia, Shellite MSDS] Retrieved August 19, 2007 </ref>
  
−
Active and passive air sampling methods for naphtha vapors are covered in this process review. Direct reading instruments and dusts and particulates are not discussed in this review.
+
* Shell Ronsonol Lighter Fuel<ref>[http://www.cooperbooth.com/datasheets/160606.pdf Shell Ronsonol Lighter Fuel MSDS] Retrieved August 19, 2007 </ref>
  
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===Air Sampling Categories: Direct Reading versus Sample Collection===
+
* MSDS for camping-stove fuels<ref>[http://www.nafaa.org/msds.html North American Fire Arts Association.] MSDS for various camping-stove fuels including several that include naphtha. Retrieved August 19, 2007 </ref>
  
−
Two categories of air sampling equipment exist, they are: direct reading and sample collection. Direct reading equipment provides immediate measurement of exposure concentration. Sample collection includes samples of air collected over a period of time and weighed and analyzed in the laboratory. Sample collection involves active and passive air monitoring methods. Air sampling instruments will be discussed during this air sampling process review; Direct reading air monitor instruments and methods will not be discussed at this time.
+
[[Benzene]] in particular is a known high-risk carcinogen, and so benzene content is typically specified in the MSDS. But more specific breakdown of particular forms of hydrocarbon is not as common.
  
−
===Sampling Methods: Active versus Passive Sampling===
+
According to J. LaDou in ''Occupational and Environmental Medicine,''<ref>J. LaDou, ''Occupational and Environmental Medicine,'' 3rd ed. (Lange Medical Books, McGraw Hill, 2004), 508.</ref> "Almost all volatile, lipid-soluble organic chemicals cause general, nonspecific depression of the central nervous system or general anesthesia." The U.S. Occupational Health and Safety Administration (OSHA) places the permissible exposure limit (PEL) at 100 parts per million (ppm); and the Health Hazards/Target Organs are listed as eyes, skin, RS, CNS, liver, and kidney. Symptoms of acute exposure are dizziness and narcosis with loss of consciousness. The World Health Organization categorizes health effects into three groups: reversible symptoms (Type 1), mild chronic encephalopathy (Type 2) and severe chronic toxic encephalopathy (Type 3).
  
−
*Active Sampling
+
==Toxicity==
−
 
 
−
Active sampling relies on sampling pumps to draw air and chemicals vapors or gases to adsorbent filter materials.
 
  
−
*Passive Sampling
+
Toxicity dose response exposures may be impacted (decreased or increased) by chemical, biological, and environmental factors.
 +
* Chemical factors include concentrations of the chemicals, their interactions with one another, dispersability, toxicity, water solubility, particle size, bioavailability, persistence in the body, and so forth.
 +
* Biological factors include stress, respiratory rate, gender, age, race, individual susceptibility, route of entry, rate of uptake, storage in the body, metabolism, and excretion.
 +
* Environmental factors can affect chemical and particulate exposures, such as by temperature, air pressure, air quality, and precipitation.
  
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Passive monitors rely on collection of gases and vapors through passive diffusion (Ficks Law) to allow personal sampling without use of pumps. Diffusion is the movement or passage of chemical molecules through a semi-permeable barrier from the source of higher concentration gradient to a lower concentration.
+
==Air sampling for naphthas==
  
−
===Sampling Types: Personal, Area, Grab and Integrated Sampling===
+
Air sampling is conducted to identify and evaluate employee or source exposures of potentially hazardous gases or particulates; assess compliance; and evaluate process or reformulation changes.
  
−
*Personal Sampling
+
Two categories of air sampling equipment exist, they are: direct reading and sample collection.
 +
* Direct reading equipment provides immediate measurement of exposure concentration.
 +
* Sample collection equipment takes samples of air over a period of time, and these samples are then weighed and analyzed in a laboratory.
 +
Sample collection involves active and passive air monitoring methods. Active sampling relies on sampling pumps to draw air and chemical vapors or gases to adsorbent filter materials. Passive monitors rely on the collection of gases and vapors through passive diffusion to allow personal sampling without use of pumps.<ref>Diffusion is the movement or passage of chemical molecules through a semi-permeable barrier from the source of higher concentration to a lower concentration.</ref>
  
−
Personal sampling is used to evaluate employee exposure to naphtha. The employee wears the sampling device that collects an air sample representative of air exposure for a specific period of time. The quantity of chemical sampled is collected on the sorbent or filter and then calculated against the total volume employee air exposure.
+
===Sampling types===
  
−
*Area Sampling
+
Various types of sampling may be used, as noted below.
  
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Area Sampling is used to evaluate background exposure to leaks and implement control measures.  
+
*Personal sampling: Personal sampling is used to evaluate employee exposure to naphtha. The employee wears the sampling device that collects an air sample representative of air exposure for a specific period of time.
  
−
*Grab Sampling
+
*Area Sampling: Area Sampling is used to evaluate background exposure to leaks and implement control measures.
  
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Grab sampling is used to monitor extremely toxic environments over a short period of time or to determine if additional air monitoring is required for over-exposure.
+
*Grab Sampling: Grab sampling is used to monitor extremely toxic environments over a short period of time, or to determine if additional air monitoring is required for over-exposure.
 
                                                              
 
                                                              
−
*Integrated Sampling
+
*Integrated Sampling: Integrated exposure sampling is used to determine the 8-hour time weighted average exposure because various exposure concentrations are integrated during the sampling period.
  
−
Integrated exposure sampling is used to determine the 8-hour time weighted average exposure because various exposure concentrations are integrated during the sampling period.
+
===Complications===
−
                                                     
 
−
===Absorption versus Adsorption===                                                                                                                                      
 
  
−
*Absorption
+
Complications with air sampling can occur in the form of interference with chemicals (alcohols, ketones, ethers, and halogenated hydrocarbons), vapors, sampling media, humidity, temperature, barometric pressure, atmospheric dust, water vapor, and container.
  
−
Gas or vapor is removed from the air stream as it passes through the absorption liquid used in impingers (gas washing bottles), fritted bubblers and midget impingers. Collection liquid can be reactive or non-reactive. Gas or vapor is separated and analyzed under laboratory conditions.
+
==Exposure Control==
  
−
*Adsorption
+
Primary methods focus on preventing chemical exposures before they occur. Personal protective equipment could include the use of air-purifying cartridges, respirators, and gloves. Engineering prevention controls would include automated handling, enclosure and elimination of harmful substances, isolation, and change of process. Ventilation controls would include local exhaust ventilation and vacuum operations. Administrative prevention controls would include changes in work practices, education, training, job rotation, job reduction, job reassignment, and proper maintenance and housekeeping.
−
 
−
"Air sampling for insoluble or non-reactive gaseous substances is commonly conducted with tubes filled with granular sorbent such as charcoal (non- polar properties) and silica gel (polar properties)." <ref name="Plog">Plog, B. A., MPH, CIH, CSP (2007) ''Fundamentals of Industrial Hygiene'', National Safety Council, , page 486</ref>  Activated charcoal is used primarily for organic vapors and has a surface area > 1000 m2/g.  Charcoal tubes are composed of coconut shell or petroleum based charcoal. Tubes vary in length and width. First section contains 100 mg of charcoal and the second section contains a number of mg of charcoal. The second section contains generally one-half the volume of the first. Breakthrough is where > 10% of mass in front section breaks through to second section and indicates that the contaminant may not have been collected properly and invalidates the results.
 
  
−
===Breathing Zone Air Sampling Procedures===
+
Secondary methods focus on early identification and treatment of chemical exposures.
−
 
 
−
*Sampling Train: Active air sampling devices consist of five sections starting at the suction pump:
 
−
**"Air inlet orifice is the opening where air enters the inlet.
 
−
**Collection devices retains chemical on the collection media as air and chemical mixture travel through collection device.
 
−
**Flow rate control valve controls the flow rate traveling through the meter.
 
−
**Air flow meter records the air flow rate traveling through the meter.
 
−
**Suction pump moves air through the collection device."<ref name="Plog"/>
 
−
 
 
−
Break both ends of sorbent tube using sorbent tube breaker. Insert sorbent tube into the rubber sleeve of the adjustable low flow holder or tube holder. The arrow on the sorbent tube indicates air flow towards the pump. In the absence of an arrow insert the end of the tube with the smallest sorbent section into the tube holder. Connect the loose end of the flexible tubing into the pump inlet.
 
−
 
 
−
===Active Air Sampling Method for Naphthas===
 
−
 
 
−
*Preparation & Calibration
 
−
 
 
−
#Prepare and calibrate the sampling equipment by charging batteries of the active sampler.
 
−
#Verify that sufficient varieties and quantities of detector tubes are available for air sampling.
 
−
#Determine the sampling technique (NIOSH, OSHA).
 
−
#Follow published air procedure/method NIOSH 1550 or OSHA 1500 for naphtha related solvents.
 
−
#Calibrate the sampler pump, sampling device, sorbent tube and with a standard rotameter.
 
−
#Set air pump sampling rate at .01 L and .2 L/min for OSHA or NIOSH.
 
−
#Record the pump rotameter reading.
 
−
#Calibrate pump rate specified in the method.
 
−
 
 
−
*Communication
 
−
 
 
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#Select the employees to be monitored.
 
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#Discuss the sampling purpose and process with the employee.
 
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#Let the employee know the sampling period length.
 
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#Instruct the employee not to tamper with air monitoring equipment.
 
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#Employee should notify industrial hygienist if they have question about equipment or equipment needs to be removed.
 
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#Employee should document unusual production or exposure events during the course of monitoring.
 
−
 
 
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*Adsorbent Tube Orientation
 
−
 
 
−
#Attach the air pump on the employee’s belt.
 
−
#The sorbent tube with more charcoal should be facing away from the pump. Place the inlet in a downward vertical position to avoid contamination
 
−
#Break open the ends of the filter or charcoal tube (with tube breaker and safety glasses) before sampling begins.
 
−
#Attach the collection device (charcoal tube or passive sampler) to the shirt collar or as close as possible to the breathing zone (in a 12 inch sphere from around the head).
 
−
#Attach the sorbent tube holder clip on the protective cover near the breathing zone.
 
−
#Place and secure (duct tape) the monitoring equipment on the employee so it does not interfere with the employees work (excess tubing should be taped out of the way as well).
 
−
#"Record location of sample, employee name and identification number, title, chemicals sampled for, starting/ending times, flow rate starting/ending flow rates, temperature, humidity, barometric pressure, active/passive sampling, sampling media, job activity." <ref name="Burton">Burton, J. (2007) ''Field Guide for Industrial Hygiene'' AIHA Press, page 8</ref>
 
−
 
 
−
*Active Air Sampler Rate Verification
 
−
 
 
−
#Turn the air pump on and document the time start.
 
−
#Record the data by sampling protocol, sampling integrity.
 
−
#Check the air monitoring pump, hose, rate and filtering devices during the air monitoring event. Record pump rotameter reading.
 
−
#Sample at the target sample rate.
 
−
#Take digital pictures, document conditions, emission sources, work practices, activities.
 
−
#Prepare blanks during the sample period (Minimum 20 % of samples). Field blanks should be subjected to same handling as the samples except that no air is drawn through them.
 
−
#Prior to pump removal verify pump rate with rotameter within the local sampling atmosphere location to account for humidity and temperature.
 
−
#Record pump rotameter reading
 
−
#"Turn off pump and record ending time." <ref name="Burton"/>
 
−
#Remove the sorbent tube, seal the ends and document any pertinent sampling information.
 
−
#Prepare the chain of custody and the samples for delivery to the lab for analysis
 
−
#Pack samples for shipment (Different methods may require preservative for shipment).
 
−
#Ship samples to AIHA accredited lab.
 
−
 
 
−
===Secondary Calibration Rotameter===
 
−
 
 
−
Rotameter consists of a float ball moving vertically in a tapered tube. Force of air flow volume pumped through the air tube counteracts gravity. Air sampling pump is calibrated against the soap bubble meter attached to sampling train. Calibration will represent the current sampling air temperatures and pressures accurate to plus or minus 5 %.
 
−
 
 
−
===Minimum Sampling Volumes===
 
−
 
 
−
Determine the minimum sampling volume required for analysis by calculating the Limit of Detection of the analytical method. Determine how much air sample must be drawn through the sample collector for sufficient capacity of analysis, prevent chemical interference and not exceed sampler capacity.
 
−
 
 
−
*Limit of Detection Formula for Analytical Method and Example:
 
−
 
 
−
Example Problem: The limit of detection for an analytical method is .01 mg. It is desired to be able to detect 0.02 mg/M<sup>3</sup>. How much air must be drawn through the sample collector?
 
−
Formula
 
−
TC = LOD  / LOQ
 
−
 
 
−
Definitions
 
−
TC = Target Concentration
 
−
LOD        = Limit of Detection for Analytical Method - OSHA 1500 & NIOSH 1550
 
−
LOQ        = Exposure Limit of Quantification in Mg/M<sup>3</sup>
 
−
 
 
−
OSHA/ NIOSH Naphtha Method: Given Values for Example
 
−
LOD = 0.01 mg
 
−
1000 L = 1 M<sup>3</sup>
 
−
LOQ = 0.2 mg/M<sup>3</sup>
 
−
 
 
−
Calculations
 
−
.01 mg/M<sup>3</sup> x 1000L /.2 L/min = 50 Liters
 
−
 
 
−
===Complications with Air Sampling===
 
−
 
 
−
Air sampling complications can be interference with chemicals (alcohols, ketones, ethers, and halogenated hydrocarbons), vapors, sampling media, humidity, temperature, barometric pressure, atmospheric dust, water vapor and container.
 
−
 
 
−
===Adsorbent Tube Advantages and Disadvantages===
 
−
 
 
−
Break through occurs from the following: sampling too fast; chemical adsorption migration greater than 10% into the second stage of the sorbent tube; and/or sampling at high analyte levels. Sorbent tubes are usually accurate to plus or minus 25% at the PEL. "Air sampling devices have unique capacities for each analyte sampled. When this capacity is exceeded; analyte breakthrough occurs. An analyte of interest can be can be displaced by an analyte more strongly adsorbed by the adsorbent."<ref>Supelco (1997). ''Monitoring Airborne Contaminants in Workplace Atmospheres, Using Sampling Devices and GC or HPLC.'' Bulletin 769G, page 7</ref>
 
−
 
 
−
"High humidity can severely reduce the breakthrough volumes of adsorbents like charcoal and silica gel."<ref>DiNardi, S (2003). ''The Occupational Environment: It’s Evaluation, Control and Management'', Second Edition, American Industrial Hygiene Association, Fairfax, Virginia, p. 182</ref>
 
−
 
 
−
===Sorbent Tube Desorption===
 
−
 
 
−
Naphtha’s sorbent tube is desorbed of collected chemical by carbon disulfide for 30 minutes.
 
−
 
 
−
===Advantages and Disadvantages of Passive Sampling===
 
−
 
 
−
Passive monitoring (badge or tube) is cheaper and easier for occupational hygienist to use and require less technical training. Diffusion sampling is less cumbersome for the wearer. Passive sampling is not impacted by pressure and temperature variations like active sampling.
 
−
 
 
−
Passive sampling disadvantages are that some chemicals are not easily retained on to diffusion sorbent. Stagnant and high face velocities do not allow for accurate diffusion onto passive diffusion samplers.
 
−
 
 
−
===Analyzing Method===
 
−
 
 
−
Naphtha’s analysis method is gas chromatography – flame ionization detector (GC – FID).
 
−
 
 
−
*Results versus Standards
 
−
 
 
−
Any sample result that is less than the OEL is usually considered to be in compliance with the law at the 95% confidence level. Exposures over the PEL and LCL may result in citations and fines. If the PEL for a chemical is 50 ppm and an employee had a TWA of 60 ppm for a 6-hour shift.  This may look like an overexposure however upon recalculation for a full work shift (8-hours) the TWA comes out to be:   
 
−
Chemical exposures may result in frequent or higher excursions during the work shift and may or may not meet the regulatory guidelines. Pregnant women, the very young and very old are more susceptible to chemical exposures.  Preferred controls remove or drastically reduce the overall exposure to an acceptable exposure level.
 
−
 
 
−
The Industrial Hygiene Code of Ethics requires placing employee health first in all considerations. If the PEL’s are not available, animal studies or toxicology data may provide guidance.
 
−
 
 
−
Limitations or disadvantages of United States PEL’s are the following: PEL’s are limited only to inhalation exposures, PEL’s apply to health guidelines established in 1989, PEL’s do not consider chronic toxicity data or sensitizers or skin notations, PEL’s considers a health exposure risk of 1:1000 risk for cancer versus environmental risks of 1:1,000,000, PEL’s fail to account for multiple exposures, and PEL’s are listed on only 10% of the chemicals used in the work place.
 
−
 
 
−
The minimum standard of care in many industries is the maintenance of airborne chemical concentrations below all existing standards, guidelines and internally generated standards. 
 
−
 
 
−
*Air Sampling PPE
 
−
 
 
−
Industrial hygienists (IH) conducting air sampling are required to wear all Federal, State and Local, customer, industry specific and company required (PPE) personal protective equipment but not limited to: steel toe boots, work trousers, work shirt, (nomex coveralls if required), nitrile gloves, hard hat minimum Type C, safety glasses, etc.
 
−
 
 
−
==Health Assessment, Interviews and Evaluation==
 
−
 
 
−
Conduct opening conference to discuss the reasons that you are there (for example: to assist management in proactive evaluation of current health conditions; for control of any current or potential health issues; and/or to anticipate potential safety and health considerations).
 
−
 
 
−
Review historical conditions by reviewing OSHA 300 Log and historical/current health surveillance programs. Surveillance programs should contain biological monitoring for biomarkers (biological markers of blood or urine) or metabolites (by-products) of exposure to various chemicals. "ACGIH, biological monitoring should be complimentary to air monitoring."<ref name="TLVs"> American Conference of Governmental Industrial Hygienists (ACGIH) (2003) ''TLV’s and BEI’s(R) Threshold Limit Values for Chemical Substances and Physical Agents, Biological Exposure Indices'' ACGIH, Cincinnati, Ohio</ref>
 
−
 
 
−
Evaluate current conditions by photographing, videotaping, and documenting work processes where potential health problems may occur. Security clearances and work site guide are recommended prior to tours and evaluation. Proprietary, health exposure, and ignition considerations should be addressed prior to walk-through.
 
−
 
 
−
Employee health complaints, symptoms, odors, interviews, etc., all lead to an air monitoring strategies. Air sampling processes follow with sample analysis and comparison against health standards lead to employee/management exposure communications.
 
−
 
 
−
Exposure information allows management to understand work place health exposures and then implement health prevention strategies to control and prevent chemical exposures. Health exposure assessment, communications, awareness, training, engineering, administrative and personal protective strategies address reduction and elimination of potential or real naphtha exposures. Individual historical and community health considerations are also taken into account.
 
−
 
 
−
==Toxicity==
 
−
 
 
−
Toxicity dose response exposures may be impacted (either decreased or increased) by the following factors. Chemical factors impact toxicity such as: concentration or quantity (harm in dose) times duration, hormesis (low dose stimulation), additivity, competition, synergism, antagonism, dispersability, water solubility, heavier or lighter than air, media exposure (liquid, gas, vapor, aerosol), molecule or particle size, toxicity of dose, toxicodynamics (what the chemical does to the body), progressive, permanent and reversible effects, bioavailability (binding or interference with the chemical), persistence, psychological impact, metals in different oxidative state, mechanism of action, sub cellular level, nanotechnology, receptors, and free radicals.
 
−
 
 
−
Individual biological factors such as stress, respiratory rate, gender, age, race, sweating, individual susceptibility, route of entry (injection, dermal, ingestion, inhalation, ocular), perfusion, affinity (binding, lipophilicity, storage) toxicokinetics (what body does to chemical), rate of uptake, detoxification excretion, elimination, transport, metabolism or biotransformation, water solubility, absorption, digestion or adsorption, systemic impact or local impact on body systems. Environmental factors impact chemical and particulate exposures such as: heat, cold, precipitation, inversions versus clear days and air pressure.
 
−
 
 
−
==Exposure Control==
 
  
−
Primary health prevention methods focus on chemical exposures prior to occurrence. Engineering prevention controls would be substitution, automation, enclosure, elimination, isolation and change of process. Ventilation controls would be local exhaust ventilation and vacuum operations.  Administrative prevention controls would be work practice change, education, training, job rotation, job reduction, work schedules, substitution, job reassignment, wet work methods, maintenance and housekeeping. Secondary health prevention methods focus on early identification and treatment of            chemical exposures for cure and treatment. Personal protective equipment could be air-purifying cartridge and powered air-purifying cartridge and supplied (air hose, self contained or re-breather) respirators; gloves (PVA, viton, neoprene). Tertiary health prevention methods are treatment and rehabilitation of employees exposed to chemical overexposure in the work place.
+
Tertiary methods include the treatment and rehabilitation of employees overexposed to harmful chemicals in the workplace.
  
 
==See also==
 
==See also==
Line 293: Line 134:
 
==References==
 
==References==
  
−
* Burton, D. J. 2002. ''Burton Field Guide for Industrial Hygiene''. Fairfax, VA: AIHA. ISBN 1931504326.
+
* Burton, D. J. 2002. ''Burton Field Guide for Industrial Hygiene.'' Fairfax, VA: AIHA. ISBN 1931504326
  
−
* McDermott, Henry J. 2004. ''Air Monitoring for Toxic Exposures''. 2nd ed. Hoboken, NJ: Wiley-Interscience. ISBN 0471454354.
+
* McDermott, Henry J. 2004. ''Air Monitoring for Toxic Exposures,'' 2nd ed. Hoboken, NJ: Wiley-Interscience. ISBN 0471454354
  
−
* Meyer, Eugene. 2004. ''Chemistry of Hazardous Materials''. 4th ed. Upper Saddle River, NJ: Pearson Prentice Hall. ISBN 0131127608.
+
* Meyer, Eugene. 2004. ''Chemistry of Hazardous Materials,'' 4th ed. Upper Saddle River, NJ: Pearson Prentice Hall. ISBN 0131127608
  
 
==External links==
 
==External links==
 +
All links retrieved November 10, 2022.
 +
* [http://www.cdc.gov/niosh/npg/npgd0664.html NIOSH Pocket Guide to Chemical Hazards: VM & P Naphtha] ''U.S. National Institute for Occupational Safety and Health''.
 +
* [http://www.cdc.gov/niosh/npg/npgd0438.html NIOSH Pocket Guide to Chemical Hazards: Naphtha (coal tar)] ''U.S. National Institute for Occupational Safety and Health''.
  
−
* [http://www.cdc.gov/niosh/npg/ NIOSH Pocket Guide to Chemical Hazards] from the US [[National Institute for Occupational Safety and Health]]
 
−
* [http://www.chemicalforums.com/index.php?page=searchmsds Search a number of sites for MSDS]
 
−
* [http://members.iinet.net.au/~mbuckler/fuel/index.shtml#whitespiritgas Different names with different meanings in different countries, for some naphtha-containing camping-stove products]
 
−
* [http://www.santos.com/Content.aspx?p=167 Cooper Basin naphtha] manufacturer's description
 
−
* [http://siri.org/msds/man/man.html Lists of many chemical manufacturer's MSDS sites]
 
−
* [http://ptcl.chem.ox.ac.uk/MSDS/ The Physical and Theoretical Chemistry Laboratory Oxford University Chemical and Other Safety Information]
 
−
*[http://toxnet.nlm.nih.gov/cgi-bin/sis/search/r?dbs+hsdb:@term+@na+naphtha NLM Hazardous Substances Databank &ndash; Naphtha]
 
  
 
[[Category:Physical sciences]]
 
[[Category:Physical sciences]]

Latest revision as of 01:20, 11 November 2022

Not to be confused with Naphthalene.
Coleman camp fuel, also known as white gas, is a common naphtha fuel used in many lanterns and torches.

Naphtha is a name given to several mixtures of liquid hydrocarbons that are extremely volatile and flammable. Each such mixture is obtained during the distillation of petroleum or coal tar, and occasionally by the distillation of wood. Accordingly, it is known by different names, such as petroleum naphtha, coal-tar naphtha, or wood naphtha.

Naphtha is used primarily as feedstock for producing a high-octane gasoline component via the catalytic reforming process. It is also used in the petrochemical industry for producing olefins in steam crackers and in the chemical industry for solvent (cleaning) applications.

Etymology

The origin of the word naphtha is unclear. It was an ancient Greek word that referred to any type of petroleum or pitch. The Greeks themselves borrowed the word from the Old Persian words nafata, naft, or neft, which were used to describe bubbling oil. Naphtha may also have been derived from the name of the Vedic Hindu god Apam Napat, the god of freshwater, sometimes described as a fire god.

Alternative names

Naphtha is known by various names, depending on its source, composition, uses, and manufacturing company. Some names include ligroin, VM&P Naphtha (Varnish Makers and Painter's Naphtha,[1] Benzin, petroleum naphtha, petroleum spirits, and naphtha ASTM. Another name is shellite (Australia)—also known as white gas (North America), white spirit, or Coleman fuel—which is a white liquid with a hydrocarbon odor. Given its high flammability and low flashpoint (less than -30 °C), it is used in many low-pressure camping stoves. Ronsonol is a brand name used in North America and is marketed as a refill fluid for cigarette lighters.

Properties

To obtain the product known as naphtha, a complex soup of chemicals is broken into another range of chemicals, which are then graded and isolated mainly by their specific gravity and volatility. As a result, the product contains a range of distinct chemicals with a range of properties. They generally have a molecular weight range of 100-215, a specific gravity range of 0.75-0.85, and a boiling point range of 70-430 °F. Their vapor pressure is usually less than 5 mm mercury.

Naphthas are insoluble in water. They are colorless (with a kerosene odor) or red-brown (with an aromatic odor). They are incompatible with strong oxidizers.[2]

Generally speaking, less dense naphthas ("light naphthas") have a higher paraffin content. They are therefore also called paraffinic naphtha. The denser naphthas ("heavy naphthas") are usually richer in naphthenes and aromatics, and they are therefore referred to as N&A's.

Production of naphtha in refineries and uses

Naphtha is obtained in petroleum refineries as one of the intermediate products from the distillation of crude oil. It is a liquid intermediate between the light gases in the crude oil and the heavier liquid kerosene. Naphthas are volatile, flammable and have a specific gravity of about 0.7. The generic name naphtha describes a range of different refinery intermediate products used in different applications. To further complicate the matter, similar naphtha types are often referred to by different names.

The different naphthas are distinguished by:

  • density (g/ml or specific gravity)
  • PONA, PIONA or PIANO analysis, which measures (usually in volume percent but can also be in weight percent):
    • Paraffin content (volume percent)
    • Isoparaffin content (only in a PIONA analysis)
    • Olefins content (volume percent)
    • Naphthenes content (volume percent)
    • Aromatics content (volume percent)

Paraffinic (or light) naphthas

The main application for paraffinic ("light") naphthas is as feedstock in the petrochemical production of olefins. This is also the reason they are sometimes referred to as "light distillate feedstock" or LDF. (These naphtha types may also be called "straight run gasoline" (SRG) or "light virgin naphtha" (LVN).)

When used as feedstock in petrochemical steam crackers, the naphtha is heated in the presence of water vapor and the absence of oxygen or air until the hydrocarbon molecules fall apart. The primary products of the cracking process are olefins (ethylene / ethene, propylene / propene and butadiene) and aromatics (benzene and toluene). These are used as feedstocks for derivative units that produce plastics (polyethylene and polypropylene, for example), synthetic fiber precursors (acrylonitrile), and industrial chemicals (glycols, for instance).

Heavy naphthas

The "heavy" naphthas can also be used in the petrochemical industry, but they are more often used as feedstock for refinery catalytic reformers where they convert the lower octane naphtha to a higher octane product called reformate. Alternative names for these types are "straight run benzene" (SRB) or "heavy virgin naphtha" (HVN).

Additional applications

Naphthas are also used in other applications, such as:

  • in the production of gasoline.
  • in industrial solvents and cleaning fluids
  • an oil painting medium
  • the sole ingredient in the home cleaning fluid Energine, which has been discontinued. You can purchase this type of naphtha at any hardware store.
  • an ingredient in shoe polish
  • an ingredient in some lighter fluids for wick type lighters such as Zippo lighters.
  • an adulterant to petrol
  • a fuel for portable stoves and lanterns, sold in North America as white gas or Coleman fuel.
  • historically, as a probable ingredient in Greek fire (together with grease, oil, sulfur, and naturally occurring saltpeter from the desert)
  • a fuel for fire spinning, fire juggling, or other fire performance equipment which creates a brighter and cleaner yet shorter burn.
  • to lightly wear the finish off guitars when preparing "relic" instruments.
  • to remove oil from the aperture blades of camera lenses, which if present can slow the movement of the blades, leading to overexposure.

Health and safety considerations

Forms of naphtha may be carcinogenic, and products sold as naphtha frequently contain some impurities that may have deleterious properties of their own.[3] Given that the term naphtha is applied to different products, each containing a variety of distinct chemicals, it is difficult to make rigorous comparisons and to identify specific carcinogens. This task is further complicated by the presence of a number of other known and potential carcinogens in modern environments.[4]

Below are links to some Material Safety Data Sheet (MSDS) specifications for different "naphtha" products, which contain varying proportions of naphtha and other chemicals. Besides giving health guidelines, they provide one of the few ways to determine what a given product contains.

  • Petroleum Ether MSDS[5]
  • Diggers Australia Shellite[6]
  • Shell Ronsonol Lighter Fuel[7]
  • MSDS for camping-stove fuels[8]

Benzene in particular is a known high-risk carcinogen, and so benzene content is typically specified in the MSDS. But more specific breakdown of particular forms of hydrocarbon is not as common.

According to J. LaDou in Occupational and Environmental Medicine,[9] "Almost all volatile, lipid-soluble organic chemicals cause general, nonspecific depression of the central nervous system or general anesthesia." The U.S. Occupational Health and Safety Administration (OSHA) places the permissible exposure limit (PEL) at 100 parts per million (ppm); and the Health Hazards/Target Organs are listed as eyes, skin, RS, CNS, liver, and kidney. Symptoms of acute exposure are dizziness and narcosis with loss of consciousness. The World Health Organization categorizes health effects into three groups: reversible symptoms (Type 1), mild chronic encephalopathy (Type 2) and severe chronic toxic encephalopathy (Type 3).

Toxicity

Toxicity dose response exposures may be impacted (decreased or increased) by chemical, biological, and environmental factors.

  • Chemical factors include concentrations of the chemicals, their interactions with one another, dispersability, toxicity, water solubility, particle size, bioavailability, persistence in the body, and so forth.
  • Biological factors include stress, respiratory rate, gender, age, race, individual susceptibility, route of entry, rate of uptake, storage in the body, metabolism, and excretion.
  • Environmental factors can affect chemical and particulate exposures, such as by temperature, air pressure, air quality, and precipitation.

Air sampling for naphthas

Air sampling is conducted to identify and evaluate employee or source exposures of potentially hazardous gases or particulates; assess compliance; and evaluate process or reformulation changes.

Two categories of air sampling equipment exist, they are: direct reading and sample collection.

  • Direct reading equipment provides immediate measurement of exposure concentration.
  • Sample collection equipment takes samples of air over a period of time, and these samples are then weighed and analyzed in a laboratory.

Sample collection involves active and passive air monitoring methods. Active sampling relies on sampling pumps to draw air and chemical vapors or gases to adsorbent filter materials. Passive monitors rely on the collection of gases and vapors through passive diffusion to allow personal sampling without use of pumps.[10]

Sampling types

Various types of sampling may be used, as noted below.

  • Personal sampling: Personal sampling is used to evaluate employee exposure to naphtha. The employee wears the sampling device that collects an air sample representative of air exposure for a specific period of time.
  • Area Sampling: Area Sampling is used to evaluate background exposure to leaks and implement control measures.
  • Grab Sampling: Grab sampling is used to monitor extremely toxic environments over a short period of time, or to determine if additional air monitoring is required for over-exposure.
  • Integrated Sampling: Integrated exposure sampling is used to determine the 8-hour time weighted average exposure because various exposure concentrations are integrated during the sampling period.

Complications

Complications with air sampling can occur in the form of interference with chemicals (alcohols, ketones, ethers, and halogenated hydrocarbons), vapors, sampling media, humidity, temperature, barometric pressure, atmospheric dust, water vapor, and container.

Exposure Control

Primary methods focus on preventing chemical exposures before they occur. Personal protective equipment could include the use of air-purifying cartridges, respirators, and gloves. Engineering prevention controls would include automated handling, enclosure and elimination of harmful substances, isolation, and change of process. Ventilation controls would include local exhaust ventilation and vacuum operations. Administrative prevention controls would include changes in work practices, education, training, job rotation, job reduction, job reassignment, and proper maintenance and housekeeping.

Secondary methods focus on early identification and treatment of chemical exposures.

Tertiary methods include the treatment and rehabilitation of employees overexposed to harmful chemicals in the workplace.

See also

Notes

  1. ↑ "NIOSH Pocket Guide to Chemical Hazards": VM & P Naphtha Retrieved August 19, 2007.
  2. ↑ NIOSH CAS No.: 8032-32-4, NIOSH "Pocket Guide to Chemical Hazards" 8030-30-6, (September 2005)8002-05-9Retrieved October 12, 2007.
  3. ↑ Report of the International Agency for Research on Cancer. Retrieved August 19, 2007.
  4. ↑ For instance, see Study of Health Outcomes in Aircraft Maintenance Personnel. Retrieved August 19, 2007.
  5. ↑ Mallinckrodt Baker, Petroleum Ether MSDS. Retrieved August 19, 2007.
  6. ↑ Diggers Australia, Shellite MSDS Retrieved August 19, 2007
  7. ↑ Shell Ronsonol Lighter Fuel MSDS Retrieved August 19, 2007
  8. ↑ North American Fire Arts Association. MSDS for various camping-stove fuels including several that include naphtha. Retrieved August 19, 2007
  9. ↑ J. LaDou, Occupational and Environmental Medicine, 3rd ed. (Lange Medical Books, McGraw Hill, 2004), 508.
  10. ↑ Diffusion is the movement or passage of chemical molecules through a semi-permeable barrier from the source of higher concentration to a lower concentration.

References
ISBN links support NWE through referral fees

  • Burton, D. J. 2002. Burton Field Guide for Industrial Hygiene. Fairfax, VA: AIHA. ISBN 1931504326
  • McDermott, Henry J. 2004. Air Monitoring for Toxic Exposures, 2nd ed. Hoboken, NJ: Wiley-Interscience. ISBN 0471454354
  • Meyer, Eugene. 2004. Chemistry of Hazardous Materials, 4th ed. Upper Saddle River, NJ: Pearson Prentice Hall. ISBN 0131127608

External links

All links retrieved November 10, 2022.

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