Pipeline Safety Stakeholder Communications

Product

Uses, Properties & Hazards

Aviation Gasoline (Avgas)

Uses – Aviation gas is a gasoline fuel prepared especially for use in reciprocating piston aircraft engines.

Properties/ Hazards – Exposure may occur via inhalation, ingestion, skin absorption and skin or eye contact.

Aviation gasoline is volatile and extremely flammable. It may contain benzene and may cause cancer (excessive exposure to benzene may cause leukemia in humans). Vapors are moderately irritating to the eyes and to the respiratory passages. Ingestion may result in vomiting. Avoid aspiration of vomitus into lungs as small quantities may result in aspiration pneumonitis. Prolonged immersion of skin in the liquid may lead to chemical burns. If liquid is accidentally aspirated into the lungs it can cause a severe inflammation of the lung.

Anhydrous Ammonia

Uses – Anhydrous ammonia is used as a fertilizer for agriculture and farming. It is also used as an industrial refrigerant in cold-storage and ice-making plants. The bulk of anhydrous ammonia transported by pipelines can be found in the Midwest.

Properties/ Hazards – Anhydrous ammonia is the liquefied form of pure ammonia gas. It is a colorless gas or liquid with an extremely pungent odor. Anhydrous ammonia has a very high ignition temperature (1,204°F). Thus, it is extremely unlikely to ignite if released in open air. There are, however, documented cases of anhydrous ammonia explosions in structures and confined locations.

Ammonia is a respiratory irritant and persons with impaired pulmonary function may be at increased risk from exposure. Exposure to anhydrous ammonia can result in burning of the eyes, conjunctivitis, skin irritation, swelling of the eyelids and lips, dry red mouth and tongue, burning of the throat, and coughing. More severe cases of exposure could result in difficulty in breathing, signs and symptoms of lung congestion, and, ultimately, death from respiratory failure due to edema.

Bitumen

Uses –Bitumen is blended with condensates for pipeline injection. The bitumen blend stream is used by refiners with heavy oil refining capabilities and is a preferred feedstock for producing asphalt.

Properties/ Hazards – Bitumen is a n extra heavy crude oil. As with all petroleum substances, crude oil may emit vapors that are heavier than air and will collect in low or enclosed areas. These vapors are simple asphyxiants in that they will displace oxygen and create an oxygen-deficient atmosphere in those areas. Hydrocarbon vapors are flammable or combustible.

Butane

See Liquefied Petroleum Gas

Carbon Dioxide

Uses – Carbon dioxide is a naturally occurring gas that is transported and used in the petroleum industry.

Properties/Hazards – Carbon dioxide is a heavy gas that is transported by pipeline as a compressed fluid consisting of more than 90% carbon dioxide molecules. It is a colorless, odorless and tasteless gas. Under normal conditions carbon dioxide is stable, inert and nontoxic. However, it is about 15 times heavier than air. When released it will sink to and collect in low points and can act as a simple asphyxiant when released in confined or enclosed areas. As such, it can displace breathing air and is considered hazardous. Carbon dioxide is also corrosive in the presence of water vapor.

Compressed Natural Gas

Uses – See Natural Gas. Compressed natural gas is often used as an alternative fuel for automobiles and industrial motors.

Properties/Hazards - Natural gas is odorless, colorless and tasteless in its natural state. It is nontoxic, but if released within an enclosed area it can displace oxygen and act as a simple asphyxiant. When mixed with the proper amount of air, it is flammable/explosive. Incomplete combustion resulting from an inadequate airflow can generate harmful byproducts such as carbon monoxide. At ambient temperatures it remains in gaseous form; however, it can be compressed (CNG) under high pressure to make it convenient for use in other applications or liquefied (LNG) under extremely cold temperatures (-260°F) to facilitate efficient transportation of the gas.

As with any compressed gas, CNG is under high pressure and must be contained in safe, approved containers and must be handled accordingly.

Condensates

Uses – Condensates include a variety of hydrocarbon extracts from natural gas and petroleum extraction operations. They are typically used to dilute and blend heavy oils. They are also used for refinery and petrochemical feedstocks.

Properties/Hazards – Condensates can be extremely flammable and toxic. Combustion can give off carbon monoxide, carbon dioxide and unidentified organic compounds. Hydrogen sulfide vapors may be present. Hydrogen sulfide is a toxic gas and exposure to relatively low concentrations of it can result in death.

As with all petroleum substances, condensates may emit vapors that are heavier than air and will collect in low or enclosed areas. These vapors are simple asphyxiants in that they will displace oxygen and create an oxygen-deficient atmosphere in those areas. Hydrocarbon vapors are flammable or combustible. Ingestion may result in vomiting. Aspiration of vomitus into lungs as small quantities may result in aspiration pneumonitis.

Crude Oil

(Low Sulfur)

(High-Sulfur)

Uses – Crude oil is unrefined petroleum that is extracted from beneath the earth’s surface through oil wells. As it comes from the well, crude oil contains a mixture of oil, gas, water and other impurities, such as metallic compounds and sulfur. Crude oil containing little or no sulfur is often referred to as “sweet crude.” Crude oil containing high concentrations of sulfur and hydrogen sulfide is commonly referred to as “sour crude.” Refinement of crude oil produces petroleum products that we use every day, such as motor oils and gasoline, as well as petrochemical feed stocks used in the production of other common, everyday products, such as plastics and pharmaceutical drugs.

Properties/Hazards – Hydrogen sulfide found in sour crude is a toxic gas and exposure to relatively low concentrations of it can result in death. Exposure may occur via inhalation, ingestion, skin absorption and skin or eye contact.

As with all petroleum substances, crude oil may emit vapors that are heavier than air and will collect in low or enclosed areas. These vapors are simple asphyxiants in that they will displace oxygen and create an oxygen-deficient atmosphere in those areas. Hydrocarbon vapors are flammable or combustible.

Distillate Fuel Oils

Uses – Distillate fuel oils include diesel fuel and fuel oils. Diesel fuel is a light hydrocarbon mixture for use in diesel engines. Diesel engines are used to power the hundreds of thousands of tractor & trailer trucks that cross our nation’s highways daily. Diesel engines are also used in passenger cars and light trucks and in marine applications. Refined fuel oil comes in two grades: Number 1 distillate (kerosene) which is used in many home heating applications, and a heavier Number 2 fuel oil used in many industrial heating and burner applications.

Properties/Hazards - Exposure to kerosene and other distillate fuel oils may occur via inhalation, ingestion, skin absorption and skin or eye contact.

Distillate fuel oil vapors are moderately irritating to the eyes and to the respiratory passages. Ingestion may result in vomiting. Aspiration of vomitus into lungs as small quantities may result in aspiration pneumonitis. These fuel oils may be absorbed by skin contact. Prolonged immersion of skin in the liquid may lead to chemical burns. If distillate fuel oil liquid is accidentally aspirated into the lungs it can cause a severe inflammation of the lung.

Ethane

Uses – Ethane is primarily used as a petrochemical feedstock.

Properties/ Hazards – Ethane is normally transported as a gas. It is a simple hydrocarbon that is a colorless, odorless and flammable gas. It is nontoxic but can act as a simple asphyxiant. Ethane may be transported as liquefied petroleum gas as part of a mixture with propane (commonly called ethane/propane mix).

Ethylene

Uses – Ethylene is primarily used as a petrochemical feedstock for various chemicals and petrochemical materials used in the manufacture of plastic products.

Properties/ Hazards – Ethylene is a simple hydrocarbon that is a colorless flammable gas with a faint odor that is slightly sweet. It is nontoxic but can act as a simple asphyxiant. Ethylene may be transported as a gas or a liquid.

Gasoline

Uses – Refined gasoline is the most commonly recognized refined petroleum product. It is universally used as a motor fuel for internal combustion, spark-ignited engines. Gasoline is refined in several grades and oxygenated compounds may be added to gasoline at the refinery to reduce emissions during combustion. A typical additive used today is methyl tertiary butyl ether (MTBE).

Properties/ Hazards - Exposure to gasoline may occur via inhalation, ingestion, skin absorption and skin or eye contact.

Gasoline is a flammable liquid. It often contains benzene and may cause cancer (excessive exposure to benzene may cause leukemia in humans). Gasoline vapors are moderately irritating to the eyes and to the respiratory passages. Ingestion may result in vomiting. Aspiration of vomitus into lungs as small quantities may result in aspiration pneumonitis. Gasoline may be absorbed by skin contact. Prolonged immersion of skin in gasoline liquid may lead to chemical burns. If gasoline liquid is accidentally aspirated into the lungs it can cause a severe inflammation of the lung.

If leaked, MTBE is readily soluble in water and may contaminate fresh drinking water sources. The Environmental Protection Agency ( EPA) has concluded that available data are not adequate to estimate potential health risks of MTBE at low exposure levels in drinking water but that the data support the conclusion that MTBE is a potential human carcinogen at high doses.

Gas Oil

Uses – Gas oil (like naphtha) is an intermediate refinery product that is not completely refined. It may be shipped via pipeline between refineries for final processing.

Properties/Hazards – As with other petroleum substances, hydrocarbon vapors are heavier than air and will collect in low or enclosed areas. These vapors are simple asphyxiants in that they will displace oxygen and create an oxygen-deficient atmosphere in those areas. Hydrocarbon vapors are flammable or combustible. Exposure to aromatic naphtha can cause skin irritation, eye irritation, headaches, dizziness, nausea and central nervous system disturbances.

Hydrogen

Uses – Hydrogen is primarily used as a petrochemical feedstock.

Properties/ Hazards – Hydrogen is normally transported as a gas. It is a simple gas that is a colorless, lighter than air, odorless and flammable gas. It is nontoxic but can act as a simple asphyxiant in confined spaces.

Hydrogen Sulfide

Uses – When extracted from crude oil and natural gas, hydrogen sulfide yields elemental sulfur, which is then sold to chemical plants and often used in the production of sulfuric acid.

Properties/Hazards - Hydrogen sulfide is a toxic, corrosive contaminant found in natural gas and crude oil. Exposures to relatively low levels of hydrogen sulfide can cause death.

Hydrogen sulfide has a strong rotten-egg odor. However, with continued exposure and at high levels, H2S may deaden a person's sense of smell. If the rotten egg odor is no longer noticeable, it may not necessarily mean that exposure has stopped. At low levels, hydrogen sulfide causes irritation of the eyes, nose and throat. Moderate levels can cause headache, dizziness, nausea and vomiting, as well as coughing and difficulty breathing. Higher levels can cause shock, convulsions, coma and death. After a serious exposure, symptoms usually begin immediately.

Jet Fuels

Uses – Jet fuels are highly refined kerosene petroleum distillates. Jet fuels are refined in several grades for use in both commercial and military aviation. Millions of gallons of jet fuel are used daily in thousands of commercial airline flights and in support of our armed forces as they carry out their mission to serve and protect our country.

Properties/Hazards – Exposure to jet fuels and other distillate fuel oils may occur via inhalation, ingestion, skin absorption and skin or eye contact.

Distillate fuel oil vapors are moderately irritating to the eyes and to the respiratory passages. Ingestion may result in vomiting. Aspiration of vomitus into lungs as small quantities may result in aspiration pneumonitis. These fuel oils may be absorbed by skin contact. Prolonged immersion of skin in the liquid may lead to chemical burns. If distillate fuel oil liquid is accidentally aspirated into the lungs it can cause a severe inflammation of the lung.

Kerosene

See Distillate Fuel Oils.

Liquefied Natural Gas

Uses – When chilled to very cold temperatures (-260°F) natural gas changes into a liquid. In this form, liquefied natural gas (LNG) takes up only 1/600th of the space that natural gas would in its gaseous state and thus can be stored and transported more efficiently. LNG can be loaded onto specially built tankers (large ships with several domed and thermally insulated tanks) and moved across the oceans to deliver gas to other countries. When LNG is received, it is warmed and changed back to its gaseous state. It can then be injected into natural gas transmission pipelines for further transportation. LNG can also be shipped by truck or stored until it is needed for regasification and use.

Properties/ Hazards – As noted, LNG takes up only 1/600th of the space that natural gas would in its gaseous state. If released from its containment LNG will begin vaporizing and expanding to its gaseous state. Initially, the cold and dense vapors will be heavier than air until the vapors approach ambient temperatures. In many cases, a visible vapor cloud will be seen, caused by the cold LNG condensing water vapor present in the surrounding air. Flammable concentrations of natural gas may extend well beyond the visible vapor cloud.

Natural gas is odorless, colorless and tasteless in its natural state. It is nontoxic, but if released within an enclosed area it can displace oxygen and act as a simple asphyxiant. When mixed with the proper amount of air, it is flammable/explosive. Incomplete combustion resulting from an inadequate airflow can generate harmful byproducts such as carbon monoxide.

Liquefied Petroleum Gas

Uses – Liquefied petroleum gas (LPG) is a mixture of gaseous hydrocarbons, primarily propane and butane and their isomers, such as ethane, which are easily liquefied under pressure and are used for residential and commercial heating, auto-propane, industrial fuel applications and petrochemical cracking. Propane and butane are often stored and transported under pressure as liquid in portable containers for use as fuel for heating and cooking applications.

LPG is usually transported through hazardous liquid transmission pipelines; however, vaporized propane and butane pipelines may also be found, especially in small distribution systems. Propane and butane may be transported individually and as a mixture of the two (commonly called butane/propane mix).

Properties/ Hazards – LPG is a tasteless, colorless and odorless gas and when transported via transmission pipelines typically will not have odorant added. An odorant (usually ethyl mercaptan) is added when LPG is offloaded to a distribution system or transport tanks truck to permit detection of vapor leakage. An LPG leak may be noticeable other than by smell. When the liquid evaporates, the cooling effect on the surrounding air causes condensation and even freezing of water vapor in the air. This effect may show itself as frost at the point of escape and thus make it easier to detect an escape of LPG. Also, because the refractive index of LPG differs from air, leaks can sometimes be seen as a 'shimmering'.

Escaping and gasifying LPG can cause severe frost burns if brought into contact with the skin. When released from pressure, LPG forms a vapor that is denser than air. Released vapor may flow along the ground and into drains, sinking to the lowest level of the surroundings. Thus, it may be ignited at a considerable distance from the source of the leakage. In calm air LPG vapor will disperse slowly. At very high concentrations in air, LPG vapor is anesthetic and subsequently an asphyxiant by diluting or decreasing the available oxygen.

LPG vapor can form a flammable (explosive) mixture when mixed with air. Escape of even small quantities of the liquefied gas can give rise to large volumes of vapor / air mixture and thus cause considerable hazard. Combustion of LPG with sufficient air produces carbon dioxide (CO2) and water vapor. However, inadequate combustion can result in the production of toxic carbon monoxide.

Methane Gas

Uses – Methane gas is often transported from landfills or sewage treatment plants to large natural gas users in the immediate region for use as a heat producing fuel. (Natural gas is composed of 94% methane.)

Properties/Hazards - Methane gas is a flammable gas often generated by the anaerobic bacterial decomposition of organic material in landfills and swamp areas. It is also generated in large amounts through the sewage treatment and disposal process. It is usually transported via pipelines in an unodorized state.

Natural Gas

Uses – Natural gas is the predominant product found in gas pipelines and, with few exceptions, is transported via pipelines in its gaseous form. Like crude oil, it is a naturally occurring resource formed millions of years ago as a result of heat and pressure acting on decayed organic material. It is extracted from wells sunk into the earth. The main ingredient in natural gas is methane (94%). Natural gas is widely used as a fuel for residential, commercial and industrial purposes. Approximately 23% of the energy consumption of the U.S. comes from natural gas. Over one-half of the homes in the U.S. use natural gas as their main heating fuel. (U. S. Dept. of Energy) Our economy and industries depend on natural gas in the production of virtually all products, such as steel, glass, paper, clothing, brick, and electricity. Natural gas is also an essential raw material for many common products, such as paints, fertilizer, plastics, antifreeze, dyes, photographic film, medicines, and explosives.

Properties/ Hazards – Natural gas is odorless, colorless and tasteless in its natural state. It is nontoxic, but if released within an enclosed area it can displace oxygen and act as a simple asphyxiant. When mixed with the proper amount of air, it is flammable/explosive. Incomplete combustion resulting from an inadequate airflow can generate harmful byproducts such as carbon monoxide. At ambient temperatures it remains in gaseous form; however, it can be compressed (CNG) under high pressure t o make it convenient for use in other applications or liquefied (LNG) under extremely cold temperatures (-260°F) to facilitate efficient transportation of the gas.

Natural Gas Liquid

Uses – Natural gas liquids (NGLs) have a variety of different uses, including enhancing oil recovery in oil wells, providing raw materials for oil refineries or petrochemical plants, and as sources of energy.

Properties/ Hazards – Natural gas liquids are associated hydrocarbons found in natural gas, including ethane, propane, butane, iso-butane, and natural gasoline. Before natural gas can be transported it must be processed and purified. NGLs are valuable by-products of natural gas processing. They are extracted or isolated, processed and sold separately.

Naphtha

Uses – Naphtha is used as an ingredient in paint thinners and solvents.

Properties/Hazards – Naphtha (like gas oil) is an intermediate refinery product that is not completely refined. It may be shipped via pipeline between refineries for final processing. As with other petroleum substances, hydrocarbon vapors are heavier than air and will collect in low or enclosed areas. These vapors are simple asphyxiants in that they will displace oxygen and create an oxygen-deficient atmosphere in those areas. Hydrocarbon vapors are flammable or combustible. Exposure to aromatic naphtha can cause skin irritation, eye irritation, headaches, dizziness, nausea and central nervous system disturbances.

Nitrogen

Uses – Nitrogen gas makes up 78.1% of the Earth’s air, by volume. Nitrogen is found in all living systems as part of the makeup of biological compounds. Nitrogen is crucial to life, as it is a component of all proteins. From an exhaustible source in our atmosphere, nitrogen gas can be obtained by liquefaction and fractional distillation. Ammonia is the most important commercial compound of nitrogen. Natural gas is reacted with steam to produce carbon dioxide and hydrogen gas. Hydrogen gas and nitrogen gas are then reacted to produce ammonia. Ammonia is easily liquefied and is used as a nitrogen fertilizer. Ammonia is also used in the production of urea, which is used as a fertilizer, used in the plastic industry, and used in the livestock industry as a feed supplement. Ammonia is often the starting compound for many other nitrogen compounds. Nitrogen gas is also used as an agent to produce inert environments.

Properties/ Hazards – Nitrogen is normally transported as a gas. It is a simple gas that is a colorless and odorless. It is nontoxic but can act as a simple asphyxiant. It has about the same density as air.

Oxygen

Uses – Oxygen is an elemental substance. It is very reactive and is a component of hundreds of thousands of organic compounds and combines with most elements. Plants and animals rely on oxygen for respiration. Hospitals frequently prescribe oxygen for patients with respiratory ailments. Oxygen is used as a petrochemical feedstock.

Properties/ Hazards – Oxygen is normally transported as a gas. It is a simple gas that is a colorless, odorless and aids in combustion. It is denser than air.

Paraxylene

Uses - Paraxylene is a refinery product primarily used as a feedstock material for producing other products such as purified terephthalic acid (PTA). PTA is used as the main raw material for most polyester fiber. Polyester fiber is used in the textile and tire industries and used in the manufacture of other polyester products.

Properties/Hazards – Paraxylene is a hydrocarbon aromatic compound which is produced from further refining of naphtha. It is a colorless, flammable liquid that has a sweet odor. Exposure to this product is extremely hazardous and it may cause both immediate and delayed health effects. It is highly toxic to aquatic organisms.

If released, paraxylene liquid quickly evaporates and forms a flammable vapor which can burn with explosive violence. The invisible vapor spreads easily and can be set on fire by many sources such as pilot lights, welding equipment, and electrical motors and switches. The fire hazard is greater as liquid temperature rises. Although it is highly dependent on combustion conditions, a complex mixture of airborne solids, liquids, and gases including carbon monoxide, carbon dioxide, and unidentified organic compounds will be evolved when this material undergoes combustion.

Immediate Health Effects:

Eye: Contact with the eyes causes irritation. Symptoms may include pain, tearing, reddening, swelling and impaired vision.

Skin: Prolonged or repeated skin contact may cause drying or defatting of the skin. Contact with the skin causes irritation. Contact with the skin may cause an allergic skin reaction. Symptoms may include pain, itching, discoloration, swelling, and blistering. Paraxylene is not expected to be harmful to internal organs if absorbed through the skin.

Ingestion: Because of its low viscosity, this material can directly enter the lungs, if swallowed, or if subsequently vomited. Once in the lungs it is very difficult to remove and can cause severe injury or death.

Inhalation: The vapor or fumes from this material may cause respiratory irritation. Symptoms of respiratory irritation may include coughing and difficulty breathing. Breathing this material at concentrations above the recommended exposure limits may cause central nervous system effects. Central nervous system effects may include headache, dizziness, nausea, vomiting, weakness, loss of coordination, blurred vision, drowsiness, confusion, or disorientation. At extreme exposures, central nervous system effects may include respiratory depression, tremors or convulsions, loss of consciousness, coma or death.

Delayed Or Other Health Effects:

Reproduction and Birth Defects: Breathing this material may cause birth defects.

Cancer: Paraxylene can cause cancer in laboratory animals, but the available information is inadequate to determine if this material can cause cancer in humans.

Target Organs: Repeated inhalation of this material at concentrations above the recommended exposure limit may cause damage to the auditory system

Petroleum Distillates

See Distillate Fuel Oils

Produced Water

Uses – Produced water is injected back into the ground to help maintain pressure in the oil field so that more oil can be produced.

Properties/Hazards – Produced water is water that's been separated from the mixture of crude oil and liquid natural gas that comes out of production wells. The water may contain traces of crude oil and other contaminants.

Propane

See Liquefied Petroleum Gas

Propylene

Uses – Propylene is a feedstock material used in the manufacture of a variety of products such as antifreeze and de-icing solutions for cars, airplanes, and boats; polyester compounds; and solvents in the paint and plastics industries. It is also used in the production of medicines, cosmetics, and food products.

Properties/Hazards – Propylene may exist as refinery grade or as a refined, polymer grade. Refinery grade propylene is a colorless gas with rotten egg odor. The odor is due to the fact that it contains hydrogen sulfide. The polymer grade is not odorized. It is a flammable gas and may cause flash fire. It can cause eye and skin injury. It is an asphyxiant in that it reduces oxygen available for breathing. If liquefied under pressure, the released product evaporates quickly and can have a severe chilling effect on eyes and skin and can cause local freezing of tissues (frostbite). Propylene is a gas and cannot usually be swallowed.

Synthetic Crude Oils

Uses – Synthetic crude oils are suitable feedstocks for refineries, which will process them into refined products like gasoline and diesel fuel.

Properties/ Hazards – Synthetic crude oils are lighter crude oils produced by upgrading. Upgrading is the process of breaking large hydrocarbon molecules (such as bitumen) into smaller ones by increasing the hydrogen to carbon ratio.

Tertiary Butyl Alcohol

Uses –Tertiary butyl alcohol (TBA) is used as a denaturant for ethanol, in the manufacturing of floatation agents, flavors, and perfumes (especially in the preparation of artificial musks); as a solvent, in paint removers; and, as an octane booster in gasoline. TBA is also used as a solvent for pharmaceuticals and as a dehydrating agent. TBA is a raw material used in the production of isobutylene, which may be used to produce Methyl-Butyl Ether (MTBE), a common gasoline additive, or to produce butyl elastomers used in the production of automobile tires. TBA may be formed in the environment through oxidation of MTBE in the atmosphere followed by hydrolysis or through microbial oxidation of MTBE in impacted aquifer materials.

Properties/ Hazards – TBA is a fuel oxygenate and is also an impurity in, and a breakdown problem of (MTBE). TBA is a significant potential groundwater contaminant due to its mobility, recalcitrant nature, and potential toxicity. Exposure to TBA can lead to irritation of mucous membranes, nausea, defatting of the skin, and intoxication. There is currently no federal drinking water standard for TBA, although some states have drinking water action levels for TBA.

Xylene

Uses – Xylene is a petrochemical that occurs naturally in petroleum and coal tar and is formed during forest fires. It is used as a solvent and in the printing, rubber, and leather industries. Xylene is used as a feedstock in the production of terephthalic acid (TPA), which is used as the main raw material for most polyester fiber. It is also used as a cleaning agent, a thinner for paint, and in paints and varnishes. It is found in small amounts in airplane fuel and gasoline.

Properties/ Hazards – Xylene is a colorless, flammable, sweet-smelling liquid. It is one of the top 30 chemicals produced in the United States in terms of volume.

Exposure to xylene affects the brain. High levels from exposure for short periods (14 days or less) or long periods (more than 1 year) can cause headaches, lack of muscle coordination, dizziness, confusion, and changes in one's sense of balance. Exposure of people to high levels of xylene for short periods can also cause irritation of the skin, eyes, nose, and throat; difficulty in breathing; problems with the lungs; delayed reaction time; memory difficulties; stomach discomfort; and possibly changes in the liver and kidneys. It can cause unconsciousness and even death at very high levels. Studies are inconclusive regarding harmful effects to unborn children resulting from exposure of the mother during pregnancy.