Engineering Design and Development Services

Safe Operating Procedure

Epoxy Systems and Fiberglass

Introduction

This safe operatingprocedure will ensure student, staff, and faculty safety during the handling,mixing, lay-up, and curing of epoxy resin systems.  The hazards of epoxy resin systems will beoutlined, and detailed procedures will be given to minimize the risk ofexposure to uncured or incompletely cured epoxy resins.

Process

Epoxy resin systems consistof an epoxy resin and a curing agent, which may be referred to as a hardener orcatalyst.  Epoxy resins can be powders, or they can be thick, clear or yellowliquids.  Curing agents react with epoxy resin monomers to form epoxyproducts. They are usually liquids with strong, unpleasant odors, and maycontain additives to enhance strength or shorten drying time. There are severaltypes of curing agents, including aliphatic and aromatic amines, andformaldehydes.  The additives can beorganic solvents such as toluene, xylene, or methyl ethyl ketone (MEK), andfillers such as sand, clay, fiberglass, or silica.  In a two-component epoxy product, the epoxyresin and the curing agent are packaged separately and must be mixed togetherjust before being used.  In asingle-component product, the resin and the curing agent are supplied in apre-mixed form.  

When epoxy resinsystems are used, the epoxy resin chemical and the curing agent combine to forma hard polymer.  Some epoxies cure in afew minutes at room temperature, while others need additional time or heat toharden.  The hardened, finished polymersare almost non-toxic, but the exposure to the uncured resin components can beharmful.
 

Safety Analysis

The chemicals inepoxy resin systems can enter the bloodstream by adsorption through the skin,accidental ingestion, or by inhalation of the vapors or dust particles.  The acute effects of overexposure areirritation of the eyes, nose, throat, and skin, skin allergies, and asthma.¹The solvent additives can cause other effects such as headaches, dizziness, andconfusion.  Specific hazards are asfollows:

Lungs:  Vaporsand spray mists of most epoxy resin system chemicals can irritate the lungs.  Some people develop asthma from the curingagents.  Symptoms of asthma include chesttightness, shortness of breath, wheezing, and coughing.  These symptoms may occur after work or atnight.  Once a person becomes allergic tocuring agents, even the dusts from sanding or grinding the hardened plasticscan cause an asthma attack.²

Skin: Epoxy resins can cause skin irritation.  Symptoms include redness, swelling, flaking,and itching on the hands, face, or other areas of contact.  Some people develop a skin allergy orsensitivity to epoxy liquids or mists.  Skinallergies may develop after just a few days of contact or after many years ofexposure to epoxies.  Sensitized skin maybecome red, inflamed, blistered, and itchy even from brief contact with epoxyresins.^3,4

Eyes, Nose, andThroat: Most epoxy resinsystem chemicals and their vapors (especially the curing agents and solvents)can irritate the eyes, nose, and throat.  Some people develop headaches as a result ofthis irritation.  If the liquids aresplashed into your eye they will sting, and they can severely damage the eye.
 

Nervous System: Solvents inhaled or absorbed through theskin can affect the central nervous system resulting in symptoms similar toalcohol (ethanol) poisoning.  Symptoms ofsolvent overexposure include headache, nausea, dizziness, slurred speech,confusion, and loss of consciousness.

Cancer: Epoxy resins causes skin cancer inlaboratory animals probably due to epichlorohydrin, a contaminant that canprobably cause cancer in humans.⁵  Certain glycidyl ethers used in epoxy productscause cancer in laboratory rats.  It isnot known if glycidyl ethers cause mutations or cancer in humans.  Bis-phenol-A is an epoxy resin component thathas been linked to breast cancer in epidemiology studies.⁶  Most other components of epoxy resin systemshave not been adequately tested to determine if they can cause cancer.

Endocrine System:  Bisphenol-A is an epoxy resin contaminant that disrupts the endocrinesystem in animals, and probably in humans, although the levels at which theseeffects are observed are being hotly debated. ^7,8,9,10

ReproductiveSystem:  Bisphenol-A may cause birth defects inanimals, and the effects on human embryos is being debated.^6,9,10  In addition, some of the diluents andsolvents in epoxy resin systems may affect reproduction.  Two solvents sometimes found in epoxy resinsystems (2-ethoxyethanol and 2-methoxyethanol) cause birth defects inlaboratory animals and reduced sperm counts in men.  Some glycidyl ethers also damage the testesand cause birth defects in test animals.  It is not known whether they have the sameeffects in humans.

Most other solventadditives have not been adequately tested to determine if they affectreproduction.  

Personal Protective Equipment

• Protective gloves:  Disposable nitrile gloves must be used during routine mixing and application, and should be sufficient to prevent skin contact with small quantities of uncured resin or curing agent.  Nitrile gloves must be changed often when there is prolonged exposure to uncured resin or curing agents.  Where solvents are to be used during spill clean-up, neoprene gloves shall be provided for the use of acetone; nitrile gloves shall be provided for the use of Freon TF; and poly-vinyl alcohol gloves shall be provided for the use of methylene chloride.
   
• Glasses:  Ordinary safety glasses with side shields should be sufficient for most small scale epoxy operations.  Employees and students who wear contact lenses or who do not wear glasses must wear splash-proof chemical goggles when mixing resins and curing agents.
  
  
• Booties: Employees and students at operations where spills may occur, such as pouring or transferring liquid resins into larger-sized molds, must wear disposable foot coverings which may be removed after the epoxy mixing and transferring operations are complete.
  
  
• Spill materials: Paper towels or adsorbent materials appropriate to the operation being performed must be on-hand to mop up any small spills.  If paper towels or adsorbent materials are used for spills, these materials must be placed in a plastic sealed bag and labeled as hazardous waste.
   
• Respirators: In general, a fitted respirator with an organic vapor cartridge is required for all lay-up work with uncured epoxy resin.  A fitted respirator or fitted dust mask is required for dry sanding of cured epoxy resins, cutting of carbon fiber composites, and for fiberglass work.  Wet sanding operations may not require a fitted respirator, but must be evaluated on a case-by-case basis by the department safety coordinator. Small operations that are conducted completely within a functional fume hood without personnel using respirators may be acceptable with the approval of the department safety coordinator.  This determination should be made with consultation with campus EH&S.  The respirator requirements for a given operation apply to everyone in the room that the operation is being conducted.

Procedures¹²

Mixing and Application of Very Small Quantities, pre-packaged in mixingbags:

1. Prior to initial use, read the Material Safety Data Sheet for the product and become familiar with the hazards of the material.
2. As minimum protection, wear disposable nitrile gloves.
3. Read and follow the directions on the package for mixing the material.
4. Place paper towels under the operation to absorb any leakage of excess material.
5. Do not leave scissors, spatulas, etc., which have been contaminated with uncured epoxies and curing agents, in areas where other people may pick them up or otherwise come into contact with them.
6. Excess material shall be allowed to harden in an adequately ventilated area. When the material is completely cured, it may be placed in the trash for disposal.
7. When cleaning up any spills or leaks, be sure to wear protective gloves. If material spills or contaminates the work area, sop up the excess material with a paper towel. Soap and water should be used to clean up any remaining material. It may be necessary to use a small amount of solvent, dispensed from a 500 ml squeeze bottle, to complete the cleaning.
8. Any needle syringes used to apply epoxies to very small components must be packaged properly for disposal. The syringe must be packaged intact (don't re-cap needle or separate the needle from the syringe) and placed in a sharps container.
   
   

Mixing and Application of Small Quantities (i.e., container sizes up toone cup)

1. Prior to beginning the operation, read the Material Safety Data Sheet for the product and become familiar with the hazards of the material.
2. Whenever containers from which curing agents will be dispensed have a capacity greater than 500 milliliters, employees and students shall not work alone and shall ensure that there are other people in the vicinity of the operation who could help in the event of an emergency.
3. Ensure that there are adequate paper towels, sand, or vermiculite nearby in the event that uncured resins or curing agents are spilled.
4. Ensure that an eyewash is located nearby to flush the eyes in the event of eye contact. If there is not an eyewash nearby, another person who can escort the affected person to an eyewash shall remain in the vicinity of the epoxy operation.
5. Place a protective sheet of paper on the table, counter, or cart where the resin is to be mixed.
6. Wear safety glasses or protective goggles.
7. Wear protective gloves.
8. Assemble any mixing devices or other equipment prior to mixing the epoxy.
9. Weigh out the correct amount of resin and curing agent into a disposable container(s) according to the manufacturer's directions and immediately replace the caps on the containers.  Hand pump dispensers must be removed from the container and placed in a separate plastic bag for storage.
10. Do not leave tools, stirrers, spatulas, etc., which have been contaminated with uncured epoxies and curing agents, in areas where other people may pick them up or otherwise come into contact with them.
11. Container and supplies contaminated with uncured epoxies and curing agents should be separated from other work areas. A sign indicating an epoxy work area should be displayed.
12. Store excess material in a laboratory fume hood or at a designated location within an adequately ventilated area and allow to harden. Uncured epoxy materials should be stored in a designated location, or a sign indicating the presence of uncured epoxies should be displayed. When the material is completely cured, it may be placed in the trash for disposal.
13. Cleaning of tools using small amounts of solvents such as acetone, dispensed from a 500 ml squeeze bottle, may be required. Any tools or brushes which must be cleaned by soaking or which would require dispensing of solvents from any containers other than a 500 ml squeeze bottle must be performed inside a laboratory fume hood.
    
    

Mixing and Application of Larger Quantities (container size greaterthan one cup)

1. Prior to beginning the operation, read the Material Safety Data Sheet for the product and become familiar with the hazards of the material.
2. Place a sign in areas where epoxy systems are dispensed, mixed, or transferred indicating that it is an epoxy work area.
3. Whenever containers from which curing agents will be dispensed have a capacity greater than 500 milliliters, employees and students shall not work alone during off-hours and shall ensure that there are other people in the vicinity of the operation who could help in the event of an emergency.
4. Ensure that there are adequate paper towels, sand, or vermiculite nearby in the event that uncured resins or curing agents are spilled.
5. Ensure that an eyewash is located nearby to flush the eyes in the event of eye contact. If there is not an eyewash nearby, another person who can escort the affected person to an eyewash shall remain in the vicinity of the epoxy operation.
6. Place a protective layer of cardboard on the floor covering the areas where resins will be mixed and transferred. Also place a protective sheet of paper any tables, counters, or other working surfaces above the floor level where the resin is to be mixed or transferred.
7. Wear glasses or protective goggles.
8. Wear protective gloves.
9. Wear protective booties. Contamination of shoes with epoxies and subsequent cleaning with solvents is not an acceptable work practice.
10. Assemble any mixing devices or other equipment prior to mixing the epoxy.
11. Resins and curing agents which are shipped in 5-gallon containers will generally be transferred into secondary containers with dispensing valves. Thick, chemical- resistant protective gloves, aprons, booties, and splash-proof safety goggles, or safety glasses with side shields shall be worn when such transfer operations take place. If the dispensing valve of the secondary container is positioned over the edge of a counter top or other working surface, a drip pan shall be placed below the dispensing valve. The drip pan shall be of an adequate size to contain any reasonably large leak through the dispensing valve.
12. Resins mixed in containers with a capacity of more than one cup shall be mixed in a laboratory fume hood whenever possible, or only in a well-ventilated area.
13. Weigh out the correct amount of resin and curing agent into a disposable container(s) and immediately close dispensing valves or replace the caps on any containers.
14. Do not leave tools, stirrers, spatulas, etc., which have been contaminated with uncured epoxies and curing agents, in areas where other people may pick them up or otherwise come into contact with them. Containers and supplies contaminated with uncured epoxies and curing agents should remain in a designated area with a sign indicating that it is an epoxy work area.
15. A vacuum-tight mold is essential for many of the applications requiring the preparation of more than one cup of epoxy resin at a time. Usually RTV silicone rubber is used. The uncured rubber, when applied to the mold, is a primary skin irritant. Therefore, employees and students shall always wear protective gloves while sealing molds.
16. Cleaning of tools using small amounts of solvent, dispensed from a 500 ml squeeze bottle, may be required. Any tools or brushes which must be cleaned by soaking or which would require dispensing of solvents from any containers other than a 500 ml squeeze bottle may only be performed inside a laboratory fume hood. Such cleaning outside of a laboratory fume hood may only be performed with permission of the supervisor.
17. Whenever compressed air is used to remove excess uncured resin from tubing or other equipment, the compressed air nozzle must be equipped with device to ensure that the air is delivered at pressures below 30 psig. The excess resin shall be collected onto a paper towel or other material which may then be placed in a container or area designated for the hardening of resin-contaminated materials. Safety glasses shall always be worn when compressed air nozzles are used.
18. Containers contaminated with resinous mixtures shall always be stored until the resin hardens and then placed in the trash.
     

Curing of EpoxyComposites

Curing of epoxy compositeswill take one week or even longer. During the curing process, epoxy components are released as vapors. 

1. All curing epoxy work pieces must be stored in a fume hood, on a downdraft table, or outdoors.
2. Curing ovens shall be vented to the outside. If this is not feasible, the curing oven shall only be operated in an open, well-ventilated room, or shall be positioned as closely as possible to an exhaust vent which is ducted to the outdoors.
3. Store excess resinous mixtures or materials which have been contaminated with resinous mixtures (e.g. booties, disposable spatulas, paper towels) in a laboratory fume hood or at a designated location within an adequately ventilated area until it hardens. A written sign should indicate the presence of curing resinous materials. When resinous materials have completely cured, the hardened resin or contaminated materials may be placed in the trash for disposal.

Dry Sanding ofcured epoxy composite materials

Dry sanding andshaping operations may result in the release of airborne concentrations of particulatesof cured epoxy or fiberglass. Particulates may accumulate on clothing or comeinto contact with the skin, resulting in adsorption of epoxies.  All dry machine-sanding operations shall beperformed only with the use of local exhaust ventilation and an appropriatefitted respirator with a particulate cartridge or a fitted dust mask.

1. Wear safety glasses or protective goggles.
2. Wear protective gloves, disposable nitrile gloves are adequate.
3. Wear clothing dedicated to epoxy sanding.  Change into uncontaminated clothing immediately after the sanding is completed for the day or session.  Contaminated clothing must be washed before using again.
4. Wear disposable booties over shoes.
5. Local exhaust ventilation must be used continuously during the sanding process.  A shop vacuum with the nozzle held near the sanding operation should be adequate to capture the particulates.
6. After the sanding is completed for the day, use the vacuum to remove all particles from the floor and the bench.  Empty the vacuum canister into a plastic bag and dispose in the trash.

Wet Sanding ofcured epoxy composite materials

Wet sanding andshaping operations may prevent the release of airborne concentrations of particulatesof cured epoxy or fiberglass if performed properly.  However, wash water contaminated with epoxyparticulates may accumulate on clothing or come into contact with the skin,resulting in adsorption of epoxies.  All drymachine-sanding operations shall be performed only with the use of localexhaust ventilation and an appropriate fitted respirator with a particulatecartridge or a fitted dust mask.

1. Wear glasses or protective goggles.
2. Wear protective gloves, disposable nitrile gloves are adequate.
3. Ensure that the sanding location remains wet at all times during the sanding operation.
4. Collect the water from the sanding operation in a trough or container, or use adsorbent to capture all of the contaminated water.
5. The water from the trough can be reused, and the adsorbent can be reused until liquid appears in the mixture.  Dispose of the wet adsorbent or the water from the collection trough as hazardous waste.

Operations Requiring SupervisorApproval

The followingoperations with epoxy composites require the approval of the EDDS Manager or EDDSSafety Coordinator before they begin:

1. Any initial experiments with new epoxy or polymer composites that have not previously been used in EDDS
   
   
2. Mixing of greater than 1 liter of epoxy or curing agent in a single container.
   
   
3. Use of powered grinding operations on cured epoxy pieces.
   
   

SpillProcedures

1. Refer to the product Material Safety Data Sheet for proper spill clean-up procedures. Do not attempt to clean up any large spills, especially if the vapors from the spill result in noticeable eye or respiratory irritation. For large spills, shut off any ignition sources, and call 911. If there is personal injury or a strong threat of personal injury, dial 911. Do not let anyone enter the spill area.
2. Small spills may be cleaned up by the person who caused the spill.
3. Do not attempt to clean up any spills without wearing gloves. If the use of solvents is required, appropriate chemical-resistant gloves shall be used (see Personal Protective Equipment).
4. If there is any possibility of contamination of footwear while cleaning up the spill, disposable foot coverings (booties) shall be worn. Cleaning epoxies from the soles of the shoes with solvents should be prevented as this is not an acceptable work practice.
5. Absorb or wipe up the excess resin system with paper towels, sand, or vermiculite. Place the materials into a suitable container and store outside or in a fume hood where the resin can be allowed to harden. Completely cured materials may be discarded in the trash.
6. If only the basic resin or the curing agent has spilled, absorb or wipe up the excess material with paper towels, sand, or vermiculite. Place the materials into a suitable container and label it as hazardous waste.
7. Final cleaning of any spill area should be done with soap and water whenever possible. The use of solvents for cleaning purposes shall be minimized. If solvents are to be used, they shall only be used after most of the material has been removed. Absorbent materials such as paper towels may be placed inside a laboratory fume hood to dry and when completely dry, placed in the trash for disposal. Do not place wet, solvent soaked towels into the trash. Contaminated absorbent materials such as sand and vermiculite may be placed into an appropriate container and labeled as hazardous waste.

References¹³

1. California Health Evaluation and Information Service, June, 1989, Epoxy Resin Systems, http://www.dhs.ca.gov/ohb/HESIS/epoxy.htm
   
   
2. Anonymous, 1977, Asthma induced by epoxy resin systems, Brit. Med. Journal, 655. http://www.pubmedcentral.nih.gov/pagerender.fcgi?artid=1631931&pageindex=1
   
   
3. Calnan, C.D., 1963, Dermatitis from Epoxy Resin Systems, Trans. Ass. Industr. Med. Offrs .13: 38. http://occmed.oxfordjournals.org/cgi/reprint/13/1/38.pdf
   
   
4. Rycroft, R. J. G., 1980, Atypical Psoriasis following Epoxy Resin Sensitization, J. Soc., Occup., Med. 30: 132.
   
   
5. U.S. Occupational Safety and Health Administration (OSHA), 2007, Chemical Sampling Information – Epichlorohydrin, U.S. Department of Labor, Washington, D. C.  http://www.osha.gov/dts/chemicalsampling/data/CH_238700.html

6. Kaiser, J. 2007, Endocrine Disrupters:  Controversy Continues After Panel Rules on Bisphenol A, Science, 317(5840): 884.
   
   
7. Takayanagi, S, T. Tokunaga, X. Liu, H. Okada, A. Matsushima, and Y. Shimohigashi, 2006, Endocrine disruptor bisphenol A strongly binds to human estrogen-related receptor y (ERRy) with high constitutive activity, Toxicology Letters, 167(2): 95.
   
   
8. Welshons, W.V., K.A. Thayer, B.M. Judy, J.A. Taylor, E.M. Curran, and F. S. vom Saal, 2003, Large effects from small exposures. I. Mechanisms for endrocring-disrupting chemicals with estrogenic activity.  Environmental Health Perspectives, 111(8), 994.
   
   
9. Thayer, K. M., and F. S. von Saal, 2002, Myths about endocrine disruption and the male reproductive system should not be propagated.  Human Reproduction, 17(2): 521.
   
   
10. Gray, G.M., J. T. Cohen, G. Cunha, C. Hughes, E.E. McConnell, L. Rhomberg, I. G. Sipes, and D. Mattison, 2004, Weight of the evidence evaluation of low-dose reproductive and developmental effects of bisphenol-A, Human and Ecological Risk Assessment, 10(5): 875.
    
    
11. Solomon, G. M., and P. M. Weiss, 2002, Chemical contaminants in breast milk: time trends and regional variability – Chemical contaminants in breast milk: mini-monograph, Environmental Health Perspectives, 110 (10): 1050.
    
    
12. Thomas, P., A. Eckman, 1992, SOP for Epoxy (revised in 1999 by C. Fiore), MIT Plasma Science and Fusion Center, Office of Environment, Safety, and Health, Cambridge, MA http://psfcwww2.psfc.mit.edu/esh/epoxy.html (portions of this document were used extensively, with permission from C. Fiore)
    
    
13. Anonymous, Safety Net 13, 2007, Office of Environmental Heath and Safety, University of California, Davis.