SOP for Epoxy

SOP for Epoxy


Plasma Science and Fusion Center

Office of Environment, Safety, and Health


190 Albany Street, NW21 2nd floor
617-253-9839 (Karen Cote)
617-253-8917 (Matt Fulton)
617-253-5982 (Bill Byford)
617-258-5473 (Nancy Masley)
Fax 617-252-1808

Be Safe or Die


Reviewed and Approved By:

PSFC Supervisor

PSFC Supervisor

Catherine L. Fiore, PSFC Safety Officer

Standard Operating Procedures for Handling and Use of Epoxy Resin Systems

Author: P. Thomas /A. Eckmann

Version: 1.5

Date: August 7, 1992; Revised July 20, 1999 by C. Fiore

Persons Responsible: Paul Thomas - NW17-276

Jack Nickerson - NW21-189

Jim Irby - NW17-120

Bill Beck - NW21-103

Chris Reddy - NW21-204

Introduction

This document will outline the hazards involved with the use of epoxy resin systems. It will also detail procedures to be followed to minimize the risk of exposure of Plasma Science and Fusion Center employees to uncured or incompletely cured epoxy resins.

Epoxy resin systems are used in numerous ways to glue, laminate, seal, and encapsulate metal components. These may be applied to surfaces in a variety of ways ranging using a syringe or paint brush to molding or impregnation under vacuum. Epoxy-impregnated fiberglass cloth is also used to wrap components. Since the procedures to be performed vary depending on the item being constructed, and projects generally are of a transient duration, this document outlines general procedures which should always be followed whenever epoxy resin systems are used.

The general types of epoxy resin systems and associated hazards are discussed in this document. Standard Operating Procedures are then discussed for the following situations:

  1. Mixing very small quantities, pre-packaged in mixing bags.

  2. Mixing of small quantities (container sizes up to one cup)

  3. Mixing of larger quantities (container sizes greater than one cup)

  4. Use of epoxy resin-impregnated fiberglass cloth

Scope

This procedure covers employee safety during the handling, mixing, lay-up, and curing of epoxy resin systems.

Safety Analysis

Failure to follow this procedure could result in skin and eye irritation or burns from direct contact with epoxy resins and curing agents; allergic sensitization from skin contact with epoxy resins and curing agents or inhalation of vapors; respiratory irritation from inhalation of vapors from epoxy resins; and other respiratory responses (e.g., allergy, asthma, shortness of breath) resulting from inhalation of vapors from epoxy curing agents. Exposure to excessive levels of vapors from solvents contained in some epoxy resins, may also result in exposure effects including central nervous system depression. Epichlorohydrin, contained in trace amounts in many epoxy resins, is a suspect carcinogen. Resins and curing agents may generate significant quantities of heat when mixed together in larger quantities, presenting a fire hazard. Dusts released from shaping operations performed on cured epoxy surfaces may be harmful depending on whether specific fillers are contained in the epoxy.

Definitions

Resins
Uncured resins are usually long-chain prepolymers which are viscous liquids or solids. They are often the condensation products of epichlorohydrin and bisphenol-A or other polyethers with terminal unreacted epoxy groups. Many variations are possible. In some instances, the curing agents may become part of the cross linked polymer.

Curing
Curing agents may be referred to as the catalyst, accelerator, hardener, agents, activator, or setting agent. Examples include aromatic or aliphatic amines, organic acid anhydrides, dibasic acids, organic peroxides, polyamide resins, fluoride compounds, polymercaptans, and phenolic materials. Examples are diethylene triamine, phthalic anhydride, and phenyl glycidyl ether.

Modifiers
Epoxy resins may be modified with plasticizers, diluents, flexibilizers, and fillers.

Primary Irritant
A primary irritant causes reaction by direct contact with the skin, eyes, or respiratory system if the concentration and exposure time are sufficient.

Sensitizer
A sensitizer may not produce any skin or respiratory effects with initial contacts, but after a period of several weeks or months, a subsequent contact will cause dermatitis or other allergic responses.

Hazard Assessment

The following components of epoxy resin systems must be considered when evaluating the health hazards of epoxies:

  1. The uncured resins;

  2. The curing agents;

  3. The fillers;

  4. The solvents, modifiers, or diluents;

  5. The cured resins.

Some uncured liquid epoxy resins are primary skin and respiratory irritants or sensitizers or both. Uncured resins in the solid state are reportedly the least irritating and are generally non-sensitizing.

Curing agents tend to be more irritating and sensitizing than the resin component. These generally contain active irritants and sensitizers. Many resin systems that cure rapidly at room temperature contain amine curing agents, which are active skin, eye, and respiratory irritants. The following curing agents are listed in order of decreasing potential for skin irritation and allergic sensitization:

  1. The simple amines - primary, secondary, or tertiary;

  2. The peroxides;

  3. The organic acid anhydrides, such as phthalic or maleic;

  4. The amine adducts and, in about the same category, the boron trifluoride amine hardeners;

  5. The amides and polyamides;

The amine curing agents can cause severe burns, irritation of the skin, or both effects. Dermatitis may result when the skin becomes contaminated with these materials. Sensitization has been demonstrated in some individuals. The sensitization may be caused either by skin contact with the curing agent or by inhalation of vapors. Eye contact with the amines may result in severe eye damage, and amine vapors may cause irritation to the eyes, nose, and throat. Modified aliphatic amines have less potential for causing these effects than the simple amines.

When a strong irritant comes into contact with the eyes, an individual experiences a powerful reflex to close the eye tightly. Therefore, in the event that a corrosive agent such as an amine hardener comes into contact with the eyes, the affected individual will probably require assistance to hold the eyelids open while the eye is flushed with water.

Organic acid anhydrides in the form of dust or vapor may be irritating to the eyes, nose, and throat. They may cause burns if allowed to remain in prolonged contact with the skin. Many anhydrides are considered to be sensitizers.

The addition of modifiers and diluents may increase the irritating properties of the resin formulations. Some reactive diluents, most notably epoxy monomers, can make the uncured epoxy part of the system a moderate to strong sensitizer.

Dust released from the sanding and machining of completely cured epoxy products is generally considered to be a nuisance dust. The presence of filler materials such as fiberglass, diatomaceous earth, and silica flour, however, may result in concentrations of airborne dust which are more toxic or irritating than nuisance dust. In addition, resins may not be completely cured for days after hardening. Therefore, inhalation of dusts from grinding, sawing, drilling, polishing, etc. of hardened but incompletely cured resins may cause allergic responses in individuals previously sensitized to uncured resins or curing agents.

Responsibilities

The supervisor or responsible person shall designate and train employees who are required to work with epoxy resin systems regarding the health hazards of such systems and appropriate work procedures. The supervisor or responsible person shall ensure that necessary supplies are kept in stock to clean up spills of uncured epoxies and hardeners. The supervisor or responsible person shall ensure that all work done with epoxy resin systems is done in accordance with good work practices in adequately ventilated areas.

Assumptions

The epoxy user shall be familiar with the hazards associated with epoxy resin systems and appropriate spill and emergency procedures described in this document.

Required Supplies and Personal Protective Equipment:

Procedures

  1. Mixing and Application of Very Small Quantities, pre-packaged in mixing bags:

    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 the thin PVC gloves available from the stock room.

    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 puncture-resistant container. These containers are available from lab supply (ext. 3-1881). When the container is full, seal the container and attach an MIT physically hazardous waste label available from the Biohazard Assessment Office. The container may then be left in the hall or next to the trash barrel for the custodian to pick up but it may not be placed in the trash.

  2. Mixing and Application of Small Quantities (i.e., container sizes up to 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. Whenever containers from which curing agents will be dispensed have a capacity greater than 500 milliliters, employees shall not work alone and shall ensure that there are other employees 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 employee who can escort the affected employee 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 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.

    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.

  3. Mixing and Application of Larger Quantities (container size greater than 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 shall not work alone during off-hours and shall ensure that there are other employees 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 employee who can escort the affected employee 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 shall always wear protective gloves while sealing molds.

    16. Curing ovens shall be vented to the outside whenever possible. 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 a laboratory fume hood or other exhaust vent which is ducted to the outdoors.

    17. 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.

    18. 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.

    19. 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 p.s.i.g. 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.

    20. Containers contaminated with resinous mixtures shall always be stored until the resin hardens and then placed in the trash. According to Massachusetts hazardous waste laws, empty shipping containers and secondary containers which contain uncured resin and curing agent, and which have less than one inch accumulation of residue remaining in them, may be placed in the trash. In accordance with MIT policy, such containers shall be capped and the labels removed. This allowance in the regulations is for sticky, adhesive materials which make it impossible to completely empty the container and which do not contain any chemicals on the Massachusetts acutely hazardous substance list. The supervisor shall always check with the Chemical Hygiene Officer whenever a new resin is purchased to ensure that it does not contain chemicals which are on the acutely hazardous substances list, and will advise employees accordingly.

  4. Use of epoxy resin impregnated fiberglass cloth

    Epoxy-impregnated fiberglass cloth contains pre-mixed resin which is stored at freezing temperatures until ready for use. The cloth is wrapped around various components and is usually allowed to harden at room temperature. The curing may be done under vacuum by sealing a vacuum bag around the piece and pumping it down. After curing, the hardened resin surface may be smoothed by sanding.

    The use of resin-impregnated fiberglass cloth presents a minimum potential respiratory hazard during lay-up. These products may cause mild skin irritation and are capable of causing skin sensitization.

    1. Sensitive individuals should be aware that these products may result in skin sensitization. If protective gloves cannot be worn during lay-up operations, protective creams which protect the skin and facilitate cleaning may be used. Such creams include Hand cream Solvent Protective, available from Lab Supply (Part No. 156600, ext. 3-1881) and Stockhausen Travabon cream (U.S. distributor: Stockhausen, Inc., P.O. Box 16025, 2408 Doyle Street, Greensboro, N.C. 27406, 919-378-9393).

    2. Wash hands thoroughly with soap and water after working with the product.

    3. Some air contaminants are released during the curing stage. Workpieces should be left to cure in open or well-ventilated areas, and vacuum pumps should be exhausted to the outside of the building.

    4. Sanding and shaping operations may result in the release of airborne concentrations of fiberglass-containing dust. All machine-sanding operations shall be performed only with the use of local exhaust ventilation. Contact the IHO (ext. 3-2596) for assistance with the selection and installation of local exhaust ventilation equipment. Respirators may be used to protect against fiberglass-containing dust; these may only be obtained through IHO.

Training

The supervisor or responsible person shall supply this procedure to affected employees and verify that they understand it. Employees should understand the health hazards of epoxy resin systems. Employees should understand that contact with epoxy resin systems which are not completely cured may cause dermatitis. The fact that the reaction may be delayed - that dermatitis may not develop for several weeks or even months after exposure has begun - should be emphasized.

If employees wish to use respirators when mixing, transferring, or laying-up epoxy resins due to the chemical vapors, such respirators shall ONLY be obtained from the Industrial Hygiene Office (ext. 3-2596). The supervisor or responsible person shall ensure that only employees who have received respirator training and have received appropriate medical exams as determined by EMS are allowed to wear respirators. Similarly, respirators for protection against airborne dust during sanding and shaping operations may only be obtained from IHO. The supervisor or responsible person shall ensure that only COMPLETELY CURED pieces are ground, sawed, drilled, polished, etc. unless appropriate respiratory protection is worn.

Spill Procedures

  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 the Industrial Hygiene Office at 3-2596. If there is personal injury or a strong threat of personal injury, dial 100. 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 required supplies).

  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 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. Contact the Safety Office (ext. 3-4736) as to how to proceed with removal of the materials for disposal. Resin or curing agent may be added to the clean-up materials, allowed to harden, and discarded in the trash only at the discretion of the supervisor.

  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. Contact the Safety Office (ext. 3-4736) as to how to proceed with removal of the materials for disposal.

First Aid Procedures

  1. Minor skin contact requires washing with soap and water. Soaking or flushing contaminated areas of the skin with water for periods up to 15 minutes is required if a large area comes into contact with the chemical, or if prolonged contact occurs. Contaminated clothing may hold the chemicals in contact with the skin without being immediately noticed. Many chemicals are absorbed through the skin, and dermatitis may later appear on skin which appears to be clean. Individuals affected with dermatitis who work with epoxies shall be examined at the MIT Medical Department and referred to the Environmental Medical Service for a follow-up.

  2. In the event of eye contact, the eye should be immediately be flushed with water. If the chemical is very irritating, it is likely that the affected individual will require assistance to hold the eye open during the flushing. Virtually all of the resins are eye irritants, and all of the curing agents are severe to extreme eye irritants. Curing agents may cause blindness if not completely removed from the eye after contact. In the event of eye contact with any part of an uncured epoxy resin system, the affected individual shall be seen at the MIT Ophthalmology Service immediately. Dial 100 for emergencies.

  3. In the unlikely event that an individual ingests any part of an epoxy resin system, dial 100. If an individual is overcome with vapors, dial 100.

References

This page maintained by Catherine L. Fiore FIORE@PSFC.MIT.EDU