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SECTION 1. CHEMICAL IDENTIFICATION

CHEMINFO Record Number: 807
CCOHS Chemical Name: Polyethylene, low-density

Synonyms:
Ethene homopolymer
Ethylene homopolymer
Ethylene polymers
LDPE
LLDPE
Low-density polyethylene
Polyethylene resins
Polyethylene wax
PE (non-specific name)
Polythene

Trade Name(s):
Alathon
Dowlex
Lupolen 4261A
Luwax
Marlex
Tyvek

CAS Registry Number: 9002-88-4
RTECS Number(s): TQ3325000
EU EINECS/ELINCS Number: 200-815-3
Chemical Family: Hydrocarbon polymer / ethylene polymer / homopolymer / polyethylene
Molecular Formula: (C2-H4)x
Structural Formula: (-CH2-CH2-)x-branch1-(CH2-CH2)y-branch2-(CH2-CH2)z-branch3

SECTION 2. DESCRIPTION

Appearance and Odour:
White, odourless, opaque, partially crystalline solid.(5,11,13,14)

Odour Threshold:
Odourless.

Warning Properties:
Poor. Odourless material.

Composition/Purity:
Polyethylene (PE) is a general name for a large family of semi-crystalline polymers, called thermoplastic resins that are made by the polymerizing ethylene gas.(2,11,13,14) Depending upon the degree of polymerization, polyethylenes can vary from low molecular weights to very high molecular weights. The three main commercial types of polyethylene are low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE).(12,13) LDPE is also known as high pressure polyethylene and is produced at pressures of 82-276 MPa (800-2725 atm). This CHEMINFO record reviews the hazards and control measures for low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE). For information on HDPE, refer to the CHEMINFO review for high density polyethylene. During various stages of production, LDPE resins will contain certain additives, such as antioxidants, thermal and light stabilizers, slip agents and antiblock agents, which may influence the overall hazards of the product.(15) LLDPE may also contain impurities such as catalyst residues used in LLDPE resin production, such as titanium, chromium and vanadium.(16) Refer to your Material Safety Data Sheet or the manufacturer/supplier for specific information on the product that you are using.

Uses and Occurrences:
Polyethylene resins have a wide range of applications, both as commodity resins and as specialty polymers. LDPE and LLPDE resins have many of the same applications. The largest application is the manufacture of thin film used for containers and bags of various sizes. LLPDE resins are used for garbage bags, garment bags, laundry, dry-cleaning bags, ice bags, grocery bags, and industrial sheeting and liners. Film manufactured from LDPE resins is used for food and non-food packaging, vapour barriers, shrink- and stretch-wrap film, and trash and can liners. LDPE and LLDPE are also used for injection-moulded products such as housewares, garbage cans, industrial containers, caps and lids; extrusion coating resins used for coating paper, cardboard or aluminum, used primarily for milk cartons and multi-wall bags; and blow-moulded products. Blow-moulded products from LLDPE include toys, large square-edged containers, tanks for agriculture and water treatment, while LDPE is used for squeeze bottles and blow-moulded drum liners. LLDPE is used for the manufacture of pipe and tubing, used for drip piping, swimming pool tubing, and household hoses; wire and cable coating in the electrical and telephone industry; electrical applications such as jacketing, moulded accessory panels and shields for semiconductors. (11,13,15) LDPE is used for wire and cable insulation; compounding; adhesives and sealants; pipe and conduit. LDPE and LLDPE are also blended together.(11,15)


SECTION 3. HAZARDS IDENTIFICATION

EMERGENCY OVERVIEW:
Colourless, odourless, opaque, partially crystalline solid. COMBUSTIBLE DUST. Can form explosive dust-air mixtures. Can burn if strongly heated. Can decompose at high temperatures forming irritating, toxic, dangerously reactive, and/or flammable compounds such as ethylene, acrylic acid and formaldehyde. Essentially non-toxic.



POTENTIAL HEALTH EFFECTS

Effects of Short-Term (Acute) Exposure

Inhalation:
There is no specific human or animal information available for polyethylene (PE) dusts, which may be generated during handling of powders or during operations, such as grinding or cutting. In general, high airborne concentrations of low toxicity dusts may cause coughing and mild temporary irritation.
PE processing usually involves the use of high temperatures. Heating of PE and additives used in its production may result in thermal decomposition. Potentially harmful chemicals may be formed, including, carbon monoxide, acrolein and formaldehyde. The exact chemicals formed depends on many factors, including the temperature of the process, the heating rate, the amount of oxygen present and the specific additives used in the PE. If there is potential for exposure, air sampling of the processes used to make PE, should be conducted to identify the specific contaminants formed.

Skin Contact:
PE dust causes no to mild irritation, based on animal information. There is no human information available.

Eye Contact:
The dust is not irritating except as a foreign object, based on animal information. Some tearing, blinking and mild temporary pain may occur as the solid material is rinsed from the eye by tears. Chemicals formed during the high temperature processing of PE may be irritating to the eyes. See "Inhalation" above for additional information.

Ingestion:
PE is low in oral toxicity, based on animal information. Other low toxicity dusts have caused mild, temporary stomach discomfort. There is no human information available for PE. Ingestion is not a typical route of occupational exposure.

Effects of Long-Term (Chronic) Exposure

Although the dust is normally considered non-toxic, the degree of hazard may vary depending on the concentration of additives, catalysts and impurities present in the polymer. In addition, high temperature processing of PE may result in the formation of potentially harmful chemicals. If applicable, refer to specific health hazard information for these compounds.

Lungs/Respiratory System:
In general, long-term exposures to high concentrations of low- toxicity dusts may cause increased mucous flow in the nose and respiratory system airways.(1) This condition usually disappears after exposure stops.
Controversy exists as to the role exposure to dust has in the development of chronic bronchitis (inflammation of the air passages into the lungs). Other factors such as smoking and general air pollution are more important, but dust exposure may also contribute.(1)
Specific conclusions about the potential long-term effects of inhaling polyethylene dust or small fibers cannot be drawn from a single case report. Severe lung impairment was experienced by a woman who had occupational exposure to high concentrations of small fibers generated from rotary-cut, recycled polyethylene flock for 7 years (at least 8 hrs/d; 5 d/wk). She had difficulty breathing, coughing and chest pain after 6 years of exposure. After another 11-12 months, she was admitted to hospital with a low fever, chest pain and a cough that produced blood. Lung nodules and enlarged lymphoid tissue were detected. Two other plant workers (one smoker) had either dry or productive cough and somewhat reduced lung function, but no nodules were detected. None of the other 13 plant workers reported any symptoms.(28) Recycled polyethylene will contain many different additives and may contain impurities. The composition of the material was not specified in this case report.

Respiratory Sensitization:
Two case reports describe occupational asthma in employees exposed to heated PE shrink wrapping.(3,4) It is not possible to conclude that PE caused the symptoms observed. Exposure to unidentified chemicals which would have been formed during heating of the PE probably caused the respiratory reactions.

Skin:
One author has observed irritant dermatitis (dry, red and itchy skin) following skin contact with some form(s) of PE. Apparently, under some circumstances, particularly when the PE is stored in cold for long periods, irritating additives may creep to the surface of the PE.(2)

Carcinogenicity:

There is no relevant human or animal information available. The International Agency for Research on Cancer (IARC) concluded that there was insufficient information available to permit an evaluation of the potential carcinogenicity of PE.(5,6)

The International Agency for Research on Cancer (IARC) has concluded that this chemical is not classifiable as to its carcinogenicity to humans (Group 3).

The American Conference of Governmental Industrial Hygienists (ACGIH) has no listing for this chemical.

The US National Toxicology Program (NTP) has not listed this chemical in its report on carcinogens.

Teratogenicity and Embryotoxicity:
There is no human or animal information available.

Reproductive Toxicity:
There is no human or animal information available.

Mutagenicity:
There is no human or animal information available.

Toxicologically Synergistic Materials:
There is no information available.

Potential for Accumulation:
In general, particles of plastic dust are not absorbed after inhalation.(7)


SECTION 4. FIRST AID MEASURES

Inhalation:
If symptoms are experienced, remove source of contamination or move victim to fresh air. Obtain medical advice immediately.

Skin Contact:
No health effects expected. If irritation does occur, wash gently and thoroughly with water and non-abrasive soap. If irritation persists, obtain medical advice immediately.

Eye Contact:
DO NOT allow victim to rub eye(s). Let the eye(s) water naturally for a few minutes. Have victim look right and left, and then up and down. If particle/dust does not dislodge, flush with lukewarm, gently flowing water for 5 minutes or until particle/dust is removed, while holding the eyelid(s) open. If irritation persists, obtain medical attention. DO NOT attempt to manually remove anything stuck to the eye(s).

Ingestion:
If irritation or discomfort occur, obtain medical advice immediately.

First Aid Comments:
All first aid procedures should be periodically reviewed by a doctor familiar with the material and its conditions of use in the workplace.



SECTION 5. FIRE FIGHTING MEASURES

Flash Point:
Not applicable.

Lower Flammable (Explosive) Limit (LFL/LEL):
Not applicable

Upper Flammable (Explosive) Limit (UFL/UEL):
Not applicable

Autoignition (Ignition) Temperature:
Self-Ignition Temperature: 349 deg C (660 deg F) (23)

Sensitivity to Mechanical Impact:
Not sensitive. Stable material.

Combustion and Thermal Decomposition Products:
The combustion and decomposition products are very hazardous because they are flammable, toxic and in some cases dangerously reactive. The main products of combustion in a fire are carbon monoxide and carbon dioxide. Incomplete combustion produces irritating, toxic fumes, including saturated and unsaturated hydrocarbons (e.g. methane, propane, ethylene), cyclic hydrocarbons (e.g. methylcyclohexane), formaldehyde and acrolein.(14,23,24) In the presence of air, thermal decomposition starts at approximately 235 deg C.(14,24) In the temperature range of 264-289 deg C, a very complex mixture of products are formed, including carbon dioxide, hydrocarbons (e.g. ethylene, propane), acids (e.g. formic acid, acrylic acid), aldehydes (e.g. acrolein, formaldehyde), ketones (e.g. acetone, methyl vinyl ketone), and alcohols (e.g. methanol, ethanol).(25,26,27)

Flammable Properties:

Specific Hazards Arising from the Chemical:
Polyethylene (PE) can be pyrolyzed and/or burn readily under the right conditions of heat and oxygen supply, and generate large amounts of dense black smoke. During a fire, PE may decompose by thermal decomposition or combustion to form irritating smoke and toxic and/or flammable gases and fumes, such as carbon monoxide, carbon dioxide, ethene, ethane, other saturated and unsaturated hydrocarbons, formic acid, acrylic acid, formaldehyde and acrolein. The behaviour of polymers in a fire is influenced by a number of factors, including the chemical composition and structure of the polymer and the presence of additives. The fire properties of polymers can be modified by the addition of fire retardants.(23,24)

Extinguishing Media:
Dry chemical powder, carbon dioxide, general purpose synthetic foams (including AFFF type), protein foams or alcohol resistant foam, water spray or fog may be used.(19,23)

Fire Fighting Instructions:
PE can burn if strongly heated and form irritating smoke and toxic and/or flammable fumes and gases. Evacuate area and fight fire from a safe distance or protected location. Approach fire from upwind to avoid hazardous and toxic decomposition products.
If possible, isolate materials not yet involved in the fire. Otherwise, fire-exposed materials should be cooled by application of hose streams. Application should begin as soon as possible and should concentrate on any unwetted portions. For a massive fire in a large area, use unmanned hose holder or monitor nozzles. If this is not possible, withdraw from fire area and allow fire to burn.
If applicable, avoid generating dust to minimize risk of explosion.

Protection of Fire Fighters:
PE may form hazardous decomposition products. Firefighters may enter the area if positive pressure self-contained breathing apparatus (NIOSH approved or equivalent) and full Bunker Gear is worn.



NATIONAL FIRE PROTECTION ASSOCIATION (NFPA) HAZARD IDENTIFICATION

NFPA - Comments:
NFPA has no listing for this chemical in Codes 49 or 325.


SECTION 9. PHYSICAL AND CHEMICAL PROPERTIES

Molecular Weight: 500-60,000 (LDPE) (11); 50,000-200,000 (LLDPE) (14)

Conversion Factor:
Not applicable

Physical State: Solid
Melting Point: 102-116 deg C (215.6- 240.8 deg F) (LDPE) (15,20); 100-125 deg C (212-257 deg F) (20); 133-138 deg C (271.4-280.4 deg F) (completely linear LLDPE) (14)
Boiling Point: LDPE undergoes thermal degradation above 235 deg C (24), while LLDPE degrades above 250 deg C (14).
Relative Density (Specific Gravity): 0.912-0.940 at 25 deg C (LDPE) (11,15). Less than 0.919 (LLDPE) (14,16); 0.918-0.935 (LLDPE) (20) (water = 1)
Solubility in Water: Insoluble
Solubility in Other Liquids: Insoluble in almost all solvents at room temperature. Most LDPE and LLDPE resins are soluble in many aromatic (xylenes and 1,2,4-trimethylbenzene), aliphatic (tetralin and decalin) and halogenated hydrocarbons (o-dichlororbenzene and 1,2,4- trichlorobenzene) at 80-100 deg C.(11,14,15)
Coefficient of Oil/Water Distribution (Partition Coefficient): Not applicable
pH Value: Not applicable
Vapour Density: Not applicable
Vapour Pressure: Zero
Saturation Vapour Concentration: Not applicable
Evaporation Rate: Not applicable

Other Physical Properties:
DIELECTRIC CONSTANT: 2.25-2.35 (LDPE) (11,15)


SECTION 10. STABILITY AND REACTIVITY

Stability:
Normally stable. Decomposes very slowly on exposure to sunlight and air.(14)

Hazardous Polymerization:
Will not occur.

Incompatibility - Materials to Avoid:

NOTE: Chemical reactions that could result in a hazardous situation (e.g. generation of flammable or toxic chemicals, fire or detonation) are listed here. Many of these reactions can be done safely if specific control measures (e.g. cooling of the reaction) are in place. Although not intended to be complete, an overview of important reactions involving common chemicals is provided to assist in the development of safe work practices.


STRONG OXIDIZING AGENTS (e.g. perchloric acid, chlorine) - may decompose PE.(15,19)
FLUORINE (gaseous or liquid fluorine-oxygen mixtures (50-100% F) - may burn or react violently.(21)
SULFURIC ACID and NITRIC ACID (fuming or concentrated) - can decompose polyethylene at 100-150 deg C.(14)

Hazardous Decomposition Products:
None

Conditions to Avoid:
Accumulation of dust, temperatures above 235 deg C, electrostatic charge, other ignition sources.

Corrosivity to Metals:
Not corrosive.

Corrosivity to Non-Metals:
Not corrosive.

Stability and Reactivity Comments:
Does not react with hydrofluoric or hydrochloric acid. It is stable to alkaline solutions of any concentration, aqueous acids, and oxidizing agents, such as potassium permanganate and potassium dichromate.(11,14)


SECTION 11. TOXICOLOGICAL INFORMATION

LDLo (oral, mouse): 5000 mg/kg (8, unconfirmed)

Eye Irritation:

Mild irritation was observed in rabbits following application of polyethylene (PE) powders (graded 1.3-7.5/110).(9)

Skin Irritation:

No to mild irritation was observed in rabbits following application of PE powders (graded 0.0-0.7/8).(9)

Effects of Short-Term (Acute) Exposure:

No harmful effects were observed in rats orally administered large amounts of PE resins.

Ingestion:
No harmful effects were observed in rats following one-time administration of 7950 mg/kg PE homopolymer (Marlex 50, form unspecified) (probably low-density PE). Similarly, no harmful effects were observed following one-time administration of 2500 mg/kg unstabilized and stabilized high-density PE in powdered form.(10, unconfirmed)

Effects of Long-Term (Chronic) Exposure:

Inhalation:
Some research has been conducted using the intratracheal route of administration (protective mechanisms in the upper respiratory tract are by-passed and the rate of administration is often very high). This research has not been evaluated here because of its questionable relevancy to occupational exposures.

Ingestion:
No harmful effects were observed in an unpublished study following ingestion of 1.25 to 5% PE homopolymer (Marlex 50) (probably low-density PE) for 90 days.(10, unconfirmed)

Carcinogenicity:
Some animal research has been conducted using implantation of PE products under the skin. These studies are not relevant to occupational exposures.


SECTION 16. OTHER INFORMATION

Selected Bibliography:
(1) Wright, G.W. The pulmonary effects of inhaled inorganic dust. In: Patty's industrial hygiene and toxicology. 4th ed. Edited by G.D. Clayton et al. Vol. I. General principles. Part A. John Wiley and Sons, 1991. p. 289-327
(2) Slovak, A.J.M. Occupational hazards of polyethylene and polypropylene manufacture. In: Industrial hazards of plastics and synthetic elastomers: progress in clinical and biological research. Edited by J. Jarvisalo, et al. Alan R. Liss, Inc., 1984. p. 309-312
(3) Gannon, P.F.G., et al. Occupational asthma due to polyethylene shrink wrapping (paper wrapper's asthma). Thorax. Vol. 47, no. 9 (Sept. 1992). p. 759
(4) Skerfving, S., et al. "Meat wrappers' asthma" caused by thermal degradation products of polyethylene. The Lancet. Vol. 1, no. 8161 (Jan. 26, 1980). p. 21
(5) International Agency for Research on Cancer. Ethylene and polyethylene. In: IARC monographs on the evaluation of the carcinogenic risk of chemicals to humans. Vol. 19. World Health Organization, 1979. p. 164-186
(6) International Agency for Research on Cancer. IARC monographs on the evaluation of carcinogenic risks to humans. Overall evaluations of carcinogenicity: an updating of IARC monographs volumes 1 to 42. Suppl. 7. World Health Organization, 1987. p. 70
(7) Consensus report for some plastic dusts. In: Scientific basis for Swedish occupational standards VIII. Edited by P. Lundberg. Arbete Och Halsa. No. 39 (1987). p. 91-100
(8) National Institute for Occupational Safety and Health (NIOSH). Polyethylene. Last updated: 1997-10. In: Registry of Toxic Effects of Chemical Substances (RTECS(R)). [CD-ROM]. Canadian Centre for Occupational Health and Safety (CCOHS). Issue: 2003-4. Also available from World Wide Web: <http://ccinfoweb.ccohs.ca/rtecs/search.html>
(9) Gad, S.C., et al. Correlation of ocular and dermal irritancy of industrial chemicals. Journal of Toxicology - Cutaneous & Ocular Toxicology. Vol. 5, no. 3 (1986). p. 195-212
(10) Walker, B, et al. Synthetic polymers. In: Patty's toxicology. 5th ed. Edited by E. Bingham, et al. Vol. 7. John Wiley and Sons, 2001
(11) Pebsworth, L.W. Olefin polymers: polyethylene: low density polyethylene. In: Kirk-Othmer encyclopedia of chemical technology. 4th ed. Vol. 17. John Wiley and Sons, 1996. p. 707-723
(12) Doak. K.W. Ethylene polymers: introduction. In: Encyclopedia of polymer science and technology. Vol. 6. John Wiley and Sons, 1986. p. 383-386
(13) Whiteley, K.S., et al. Polyolefins: polyethylene. In: Ullmann's encyclopedia of industrial chemistry. 5th completely revised ed. Vol. A 21. VCH Verlagsgesellschaft, 1992. p. 487-518
(14) Kissin, Y.V. Olefin polymers: polyethylene: linear low density polyethylene. In: Kirk-Othmer encyclopedia of chemical technology. 4th ed. Vol. 17. John Wiley and Sons, 1996. p. 756-784
(15) Doak, K.W. Ethylene polymers: low density polyethylene (high pressure). In: Encyclopedia of polymer science and technology. Vol. 6. John Wiley and Sons, 1986. p. 386-429
(16) James, D.E. Linear low density polyethylene. In: Encyclopedia of polymer science and technology. Vol. 6. John Wiley and Sons, 1986. p. 429-454
(17) Schwab, R.F. Dusts. In: Fire protection handbook. Edited by G.P. McKinnon. 15th ed. National Fire Protection Association, 1981. p. 4-84 to 4-97
(18) Grossel, S.S. Safety considerations in conveying of bulk solids and powders. Journal of Loss Prevention in the Process Industries. Vol. 1 (Apr. 1988). p. 62-74
(19) The Sigma-Aldrich library of chemical safety data. Ed. II. Vol. 2. Sigma-Aldrich Corporation, 1988
(20) Aldrich handbook of fine chemicals and laboratory equipment, 2003-2004. Sigma-Aldrich Fine Chemicals, 2003. p. 1509
(21) Fire protection guide to hazardous materials. 13th ed. Edited by A.B. Spencer, et al. National Fire Protection Association, 2002. NFPA 491
(22) National Institute for Occupational Safety and Health (NIOSH). Particulates, Not Otherwise Regulated, Total. In: NIOSH Manual of Analytical Methods (NMAM(R)). 4th ed. Edited by M.E. Cassinelli, et al. DHHS (NIOSH) Publication 94-113 (Aug. 1994). Available from World Wide Web: <http://www.cdc.gov/niosh/nmam/nmammenu.html>
(23) Hilado, C.J. Flammability handbook for plastics. 3rd ed. Technomic Publishing Co., 1982. p. 27-65, 137-158
(24) Troitzsh, J.,ed. Plastics flammability handbook: principles, regulations, testing and approval. Hanser Gardner Publications, Inc., 2004. p. 47-51, 58-62, 133-162
(25) Grassie, N., et al. Products of thermal degradation of polymers. In: Polymer handbook. 3rd ed. Edited by J. Brandrup, et al. John Wiley and Sons, 1989. p. II-366
(26) Hoff, A., et al. Degradation products of plastics. Polyethylene and styrene-containing thermoplastics: analytical, occupational and toxicological aspects. Scandinavian Journal of Work, Environment and Health. Vol. 8, suppl. 2 (1982)
(27) Hoff, A., et al. Thermo-oxidative degradation of low-density polyethylene close to industrial processing conditions. Journal of Applied Polymer Science. Vol. 26 (1981). p. 3409-3423
(28) Barroso, E., et al. Polyethylene flock-associated interstitial lung disease in a Spanish female. European Respiratory Journal. Vol. 20, no. 6 (Dec. 2002). p. 1610-1612

Information on chemicals reviewed in the CHEMINFO database is drawn from a number of publicly available sources. A list of general references used to compile CHEMINFO records is available in the database Help.


Review/Preparation Date: 2004-04-22



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