If You Wear Contact Lenses in the School Laboratory *

Title

Laboratory Safety Manual - Chapter 05: Protective Clothing and Equipment

Introduction

This chapter describes the various types of protective equipment and clothing that can protect you while working in the lab. Details for safe use, care, and acquisition are given for eye/face protection, gloves, lab apparel, foot protection, and respiratory protection.

Table of Contents

1. Eye and Face Protection
   1. Safety Glasses
   2. Goggles
   3. Face Shields
   4. Cost, Care and Reclamation
   5. Contact Lenses
2. Use of Gloves
3. Laboratory Clothing and Protective Apparel
4. Foot Protection
5. Respiratory Protection
6. Appendix 5-A: Information for Employees Using Respirators When Not Required Under the Respiratory Protection Standard
7. Appendix 5-B: Glove Selection

I. Eye and Face Protection

University policy on eye protection requires students, faculty, staff, and visitors in laboratories wear eye protective devices during any experiment or laboratory procedure (regardless of anticipated eye hazards). The type of safety device required depends on the nature of the hazard and the frequency with which the wearer encounters it. There are three basic types of eye and face protection that meet the majority of University laboratory requirements: safety glasses with side shields, goggles, and face shields. Each of these meets basic eye protection standards for frontal exposure to flying particles. Laboratory supervisors must determine the appropriate level of eye protection for particular tasks, and enforce eye protection rules.

Safety Glasses

Ordinary prescription glasses do not provide adequate protection from injury to the eyes. Adequate eye protection requires the use of hardened-glass or plastic safety spectacles with side shields (Figure 5.1). Safety glasses used in the laboratory must comply with the Standard for Occupational and Educational Eye and Face Protection (Z87.1) established by the American National Standards Institute. This standard specifies a minimum lens thickness of 3 mm, impact resistance requirements, passage of a flammability test, and lens-retaining frames.

Three important dimensions for fit and comfort include temple length, nose bridge width, and lens diameter. Safety spectacles with side shields, bendable temples, and universal nose bridges are available in several lens diameters. Prescription safety spectacles are recommended for employees wearing glasses. Contact EHS for information on obtaining prescription safety glasses. Do not wear photogrey (transition) lenses indoors in laboratory environments, because the percentage of light transmitted under normal light conditions is below ANSI standards. Wear chemical splash goggles or full-face shields (Figure 5.2) when significant liquid splash hazards exist. The side shields on safety glasses offer some protection from objects approaching from the side, but do not provide adequate splash protection.

Goggles provide a tighter face seal than safety glasses, and are not for general laboratory use. Wear them when there is a hazard from splashing chemicals or flying particles. For example, wear goggles when using glassware under reduced or elevated pressure, or using glass apparatus in combustion or other high temperature operations. Impact-protection goggles have perforated sides to provide ventilation and reduce fogging of the lens, but do not offer full protection against chemical splashes. Use chemical goggles with splash-proof sides for protection from harmful chemical splash.

There are also specific goggles and masks for glassblowing and intense light sources such as welding or lasers. For questions about laser safety, including eye protection, consult the UNC Laser Safety Manual or the Radiation Safety Manual or contact EHS at 919-962-5507.

Goggles

Goggles or safety glasses alone do not meet ANSI standards for protection to the face and neck. When you need greater protection from flying particles and harmful liquids, wear full-face shields that protect the face and throat (Figure 5.2). For full protection, always wear a pair of safety glasses or goggles when wearing a face shield. A metal-framed "nitrometer" mask offers greater protection for the head and throat from hazards such as flying glass or other light fragments. Consider using a face shield or mask when operating a vacuum system (which may implode), or conducting a reaction with the potential for mild explosions. Always use a UV-blocking face shield when working with transilluminators or other devices that produce ultraviolet radiation.

Cost, Care and Reclamation

The University is committed to a policy of providing eye and face protection devices without cost to students, employees and visitors. Each department is responsible for funding its eye and face protection program. The employee and/or student are responsible for scheduling and payment for eye examinations to obtain safety glasses prescriptions. Eye protective devices issued to employees, students and visitors remain the property of the University. Persons issued eye protective devices return it when the use of the device is no longer necessary. For students, this is normally at the end of each semester, and for employees upon termination of employment or change in duties where eye protection is no longer required. The department shall determine the disposition of prescription glasses. You may replace eye protective devices damaged during normal wear and use without charge at the discretion of the department head or designated administrative officer. Replacement of lost or stolen devices is the responsibility of the employee or student issued the equipment.

Eye protective devices are personal items, issued for the exclusive use of each individual. Clean with soap and water and store in a clean, protected area. Thoroughly clean and disinfect all eye protective devices before issuing to another person.

Contact Lenses

The National Society to Prevent Blindness points out that contact lenses do not provide adequate eye protection for hazardous operations and must be worn in conjunction with approved safety eyewear. The University permits the wearing of contact lenses in laboratories, only if the wearer has other forms of eye protection mentioned above. Earlier guidance recommended against wearing of contact lenses in laboratories, due to concerns about lenses trapping chemicals. However, several years of subsequent studies have shown that contact lenses do not create an additional hazard; in fact, the improved visual acuity from contact lenses might help prevent accidents, compared to no corrective lenses.

Figure 5.1 - Three types of safety glasses, each with a different method for approved side-shield protection

Figure 5.2

II. Use of Gloves

Wear proper protective gloves for potential contact with corrosive or toxic materials, materials of unknown toxicity, sharp edged objects, and very hot or cold materials. Select gloves based on the material handled, the particular hazard involved, and their suitability for the operation conducted.

Chemicals eventually permeate all glove materials. However, gloves are safe for limited periods if one knows the specific use and glove characteristics (such as thickness and permeation rate and time). Common glove materials include neoprene, polyvinyl chloride, nitrile, butyl, and natural rubbers (latex). These materials differ in their resistance to various substances (Appendix 5-B). Consider double gloving (the wearing of two gloves on each hand) when handling highly toxic or carcinogenic materials. Before each use, inspect gloves for discoloration, punctures, and tears. Before removal, wash gloves if the material is impermeable to water. Dispose single-use gloves after they are contaminated, or after you have removed them. Do not reuse single-use disposable gloves. Always store gloves properly (e.g. away from windows, transilluminators, etc.), since some glove materials are susceptible to ultraviolet damage.

Laboratory gloves have a shelf life stamped on the box. Dispose gloves if they are old. You can dispose gloves in the regular trash if they are not contaminated with bloodborne pathogens, radionuclides, highly toxic chemicals, or select carcinogens. For gloves contaminated with these substances, dispose in the proper waste stream. Do not dispose of contaminated gloves in a manner that could expose other personnel.

While it is important to wear gloves while performing laboratory manipulation of potentially hazardous materials, it is equally important to remove gloves before contacting "clean" areas such as food area surfaces, or common equipment such as telephones, computer keyboards, and photocopiers. Do not wear gloves outside the laboratory, as you could possibly contaminate surfaces you touch such as doorknobs, elevator buttons, or restroom fixtures (Figure 5.3). Remove your gloves even if you believe they are non-contaminated, as others do not know if you might have handled hazardous materials with your gloved hand(s). Consider posting a reminder at the exit door to your lab so that you do not wear lab gloves into common areas of your building. Use secondary containment for items that you must transport from your lab but do not want to touch with bare hands (e.g. samples susceptible to RNAse).

Figure 5.3 - Examples of improper use and disposal of gloves.
(Left): Gloves left on while using telephone.
(Center): Gloves left on while touching elevator buttons.
(Right): Glove with unknown contamination left in elevator.

Wear sturdier gloves such as leather for handling broken glassware, inserting glass tubes into rubber stoppers, and similar operations where you do not need protection from chemicals. Use insulated gloves when working at temperature extremes. Various synthetic materials such as Nomex® and Kevlar® can briefly withstand temperatures up to 1000 °F (538 °C). Gloves made with these materials or in combination with other materials, such as leather, are available. Do not use gloves containing asbestos, a regulated carcinogen under OSHA. Contact EHS for disposal of any asbestos containing gloves. The laboratory supervisor must determine the need for specialized hand protection in any operation, and ensure that needed protection is available.

Do not wear woven gloves while working with cryogens as the liquid may work its way through the glove to your hand. Use gloves specifically designed for work with cryogens. Gloves worn for working with elevated temperatures may not be appropriate for working with extremely low temperature liquids.

III. Laboratory Clothing and Protective Apparel

The clothing you wear in the laboratory can affect your safety. Do not wear loose (e.g., saris, dangling neckties, oversized or ragged laboratory coats), skimpy (e.g., shorts, halter-tops), or torn clothing in the laboratory. Loose or torn clothing and unrestrained long hair can easily catch fire, dip into chemicals, or become ensnared in apparatus and moving machinery. Skimpy clothing offers little protection to the skin in the event of chemical splash. If the possibility of chemical contamination exists, cover any personal clothing that you wear home with protective apparel. Finger rings can react with chemicals, and you should avoid wearing them around equipment with moving parts. Appropriate protective apparel is advisable for most laboratory work and may be required for some. Such apparel can include laboratory coats and aprons, jump suits, special boots, shoe covers, and gauntlets, which can be washable or disposable in nature. Commercial garments are available to protect from chemical splashes or spills, heat/cold, moisture, and radiation.

Laboratory coats help prevent contact with dirt and the minor chemical splashes or spills encountered in laboratory-scale work. The cloth laboratory coat is, however, primarily a protection for clothing and may itself present a hazard (e.g., combustibility) to the wearer. Cotton and synthetic materials such as Nomex® or Tyvek® are satisfactory, whereas rayon and polyesters are not. Laboratory coats do not significantly resist penetration by organic liquids. Remove your lab coat immediately upon significant contamination.

Do not take lab coats home and launder them because of the potential for contamination of the home environment. Currently, University Auxiliary Services offers a service through an outside vendor (e.g., Servitex) to clean, fold and press lab coats, or to clean, dry, and fold other items (lab cloths or towels). Contact University Auxiliary Services at 919-962-1261 for costs and to arrange for pick-up and delivery of lab coats. Check with your department's business manager to find out if your department already has an arrangement for laundering lab coats. Plastic or rubber aprons provide better protection from corrosive or irritating liquids but can complicate injuries in the event of fire. Furthermore, plastic aprons accumulate a considerable charge of static electricity, so avoid use in areas with flammable solvents or other materials ignitable by static discharge.

In some cases, disposable outer garments (e.g., Tyvek®) are preferable to reusable ones. One example is handling appreciable quantities of known carcinogenic materials, for which EHS also recommends long sleeves and gloves. Wear disposable full-length jump suits for high-risk exposure situations, which may also require the use of head and shoe covers. Many disposable garments, however, offer only limited protection from vapor penetration and you need to exercise considerable judgment when using them. Impervious suits fully enclosing the body may be necessary in emergencies.

Know the appropriate techniques for removing protective apparel if contaminated. Chemical spills on leather clothing accessories (watchbands, shoes, belts, etc.) are especially hazardous, since many chemicals absorb in the leather, which holds the chemical close to the skin for long periods. Remove such items promptly and decontaminate or discard them to prevent chemical burns.

IV. Foot Protection

Wear shoes at all times in laboratories or other chemical use and storage areas. Do not wear perforated shoes, sandals, or cloth sneakers in laboratories or mechanical work areas (Figure 5.4). Safety shoes protect the feet against injuries from heavy falling objects, crushing by rolling objects, or lacerations from sharp edges. Safety shoes are required for employees whose job duties require the lifting, carrying, moving, etc. of objects weighing more than fifteen pounds which, if dropped, would likely result in a foot or toe injury.

According to the state personal protective equipment policy, employees required to wear safety shoes can receive a subsidy for one pair of shoes per year. Contact your department if you have questions about whether your job duties require safety shoes, and your eligibility for this subsidy. Contact EHS for further questions about foot protection.

Figure 5.4
Open-toe shoes (left) are not appropriate for laboratory environments, as they offer no protection from dropped or spilled chemicals, containers, or apparatus. Wear sturdy closed-toe shoes (example on right) in the laboratory.

V. Respiratory Protection

Respiratory protection might be necessary when working with highly toxic chemicals, biological hazards, or dusts known to cause asthma or pulmonary fibrosis. However, respirators are a "last line" of defense, and should not be used until all engineering controls (e.g. ventilation) and work practice controls (e.g. product substitution) are exhausted. Respirators have specific regulatory requirements for equipment certification, fit testing, medical evaluation, and training. These requirements are from the OSHA Respiratory Protection Standard 29 CFR 1910.134. Requirements differ based on respirator type.

Figure 5.5
(Left) Comfort mask with single strap. (Right) Surgical masks.
Do not wear these for respiratory protection, as they are not respirators per the OSHA Respiratory Protection Standard (29 CFR 1910.134) and are not certified by NIOSH.

The respirator regulations do not cover "comfort masks" or surgical masks (Figure 5.5). These are technically not respirators, as they are not certified by NIOSH (the National Institute for Occupational Safety and Health), and have no protection factor rating. If you are using these masks in the lab, consider whether you might need a true respirator such as those depicted in Figure 5.6.

Figure 5.6 - Several types of NIOSH-certified respirators.
Left to right: N95 disposable respirator (with two straps), powered air-purifying respirator (PAPR), half-face air-purifying respirator (APR), full-face APR, supplied-air respirator, self-contained breathing apparatus (SCBA).

Because of the training, fit testing, and medical evaluation requirements, you cannot "casually" wear true respirators in the lab. If you wish to wear an N95 disposable respirator, you must receive training on its proper use and limitations. This training is available online.

Other types of respirators such as APRs, PAPRs, SARs, and SCBAs have more rigorous training and fit testing requirements. Contact EHS if you are contemplating their use. If you will use any type of respirators voluntarily, including N95 disposable respirators, you must read and understand the information included in Appendix 5-A at the end of this chapter.

Appendix 5-A: Information for Employees Using Respirators When Not Required Under the Respiratory Protection Standard

Respirators are an effective method of protection against designated hazards when properly selected and worn. Respirator use is encouraged, even when exposures are below the exposure limit, to provide an additional level of comfort and protection for workers. However, if a respirator is used improperly or not kept clean, the respirator itself can become a hazard to the worker.

Sometimes, workers may wear respirators to avoid exposures to hazards, even if the amount of hazardous substance does not exceed the limits set by OSHA standards. If your employer provides respirators for your voluntary use, of if you provide your own respirator, you need to take certain precautions to be sure that the respirator itself does not present a hazard.

You should do the following:

1. Read and heed all instructions provided by the manufacturer on use, maintenance, cleaning and care, and warnings regarding the respirators limitations.
2. Choose respirators certified for use to protect against the contaminant of concern. NIOSH, the National Institute for Occupational Safety and Health of the U.S. Department of Health and Human Services, certifies respirators. A label or statement of certification should appear on the respirator or respirator packaging. It will tell you what the respirator is designed for and how much it will protect you.
3. Do not wear your respirator into atmospheres containing contaminants for which your respirator is not designed to protect against. For example, a respirator designed to filter dust particles will not protect you against gases, vapors, or very small solid particles of fumes and smoke.
4. Keep track of your respirator so that you do not mistakenly use someone else's respirator.

Reference: 29 CFR 1910.134, Appendix D

Appendix 5-B: Glove Selection

The Internet resources provided will help you select the best glove and provide the most protection. For chemical mixtures or multiple hazards, pick the glove with the highest resistance to the most toxic substance or consider a double-glove protocol. If you are in doubt, do not hesitate to call the manufacturer's representative for technical assistance or EHS.

Choosing the right protective glove for the job is critical to safe handling of animals as well as hazardous and toxic chemicals and other laboratory tasks. Match the individual glove by manufacturer and style to the required task and exposure particulars. No single glove will protect against all harmful substances. Nor will one glove suit all applications. No matter which glove is used, they all can potentially leak or become punctured or torn. No glove can offer 100% protection either, as permeation and degradation take their toll during use. To ensure the highest level of protection train employees to know the hazards of the substances they handle and the estimated breakthrough times for the gloves selected. Always handle toxic and hazardous chemicals with utmost care.

Resources

• Ansell
• HexAmour
• Kimberly Clark
• Mapa
• Microflex
• Saf-T-Gard
• University of Florida – Glove Use in Laboratories

Adapted from "All Hands on Deck: a primer on protective gloves" by Vince McLeod, CIH; ALN; 2010-06-24

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If You Wear Contact Lenses in the School Laboratory *

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