Handling of Chemicals

Handling of Chemicals

General

Know the physical and health hazards associated with the chemicals you are using. Carefully read the chemical's label and safety data sheet (SDS) before using a chemical for the first time. Also review the appropriate Standard Operating Procedure. These documents will provide any special handling information that you may need. After the potential hazards associated with the chemicals and the experimental processes are evaluated you can modify work procedures so that laboratory hazards are minimized or eliminated.
When handling chemicals:

• Do not work alone in the laboratory. If you do need to work alone notify someone.
• Wear required personal protective equipment including lab coat, safety glasses (or goggles and face shield when appropriate) and gloves.
• Label all containers with chemical content.
• Wear disposable nitrile gloves to prevent skin exposure
• Keep your hands and face clean. Wash thoroughly with soap and water after handling any chemical and whenever you leave the lab.
• Avoid direct contact with any chemical. Always wear a laboratory coat.
• Keep chemicals off your hands, face and clothing, including shoes.
• Never smell, inhale or taste a chemical.
• Smoking, drinking, eating and the application of cosmetics is forbidden in areas where hazardous chemicals are used or stored.
• Always use chemicals with adequate ventilation or in a chemical fume hood. Refer to the sds and the standard operating procedure to determine what type of ventilation is needed.
• Use hazardous chemicals only as directed and for their intended purpose.
• Inspect equipment or apparatus for damage before adding a hazardous chemical. Do not use damaged equipment.
• Never use mouth suction to fill a pipette. Use a pipette bulb or other pipette filling device. (See the Biosafety Manual for more on pipetting.)
• Electrically ground and bond containers using approved methods before transferring or dispensing a flammable liquid from a large container.

For specific information regarding chemical handling, contact your supervisor, instructor or EHRS.

Laboratory Fume Hoods

Local exhaust ventilation is the one of the best engineering methods available to reduce the health hazard risk associated with the use of hazardous chemicals in the laboratory. Laboratory fume hoods* are the most common local exhaust ventilation devices found in the laboratory. Fume hoods are used to prevent hazardous, offensive, or flammable gases and vapors from mixing with the general room air. A hood, especially with the sash down, acts as a physical barrier between the laboratory workers and chemical reactions. The hood can also contain accidental spills of chemicals.
* Note that laboratory fume hoods and biosafety cabinets, although similar in appearance, are extremely different devices. Biosafety cabinets are used for protection against exposure to biological materials and should not be used with chemicals unless properly vented. If you are uncertain about the type of hood in your laboratory check with the principal investigator.
Check the sds, appropriate Standard Operating Procedure, or chemical label for special ventilation requirements, such as:

• Use with adequate ventilation
• Use in a fume hood
• Avoid inhalation of vapors
• Provide local ventilation

Ventilation recommendations must be adapted to the work site and the specific process.

Reporting Fume Hood Problems

Check your hood before each use. Contact your building administrator if the alarms sounds or if you detect a problem. The building administrator will place an orange Hood Out of Order sign on the sash of the hood. A hood must never be used when this orange sign is present.
A mechanic will evaluate the hood and make the necessary repairs. Once the hood is repaired it will be flow tested by Environmental Health and Radiation Safety. If the hood's face velocity is adequate the orange sign will be removed. Persistent problems with fume hoods or repair delays longer than 5 working days should be reported to EHRS.
To be effective, laboratory fume hoods must be installed and used correctly. The National Research Council in Prudent Practices for Handling Hazardous Chemicals in Laboratories; (1981) recommends that the following factors be remembered in the daily use of hoods:

1. Hoods should be considered as backup safety devices that can contain and exhaust toxic, offensive, or flammable materials, when the design of an experiment fails. Hoods should not be used as a means for disposing of chemicals. Thus, apparatus used in hoods should be fitted with condensers, traps, or scrubbers to contain and collect waste solvents or toxic vapors or dusts.
2. Hoods should be evaluated before use to ensure adequate face velocities (typically 60-100 fpm) and the absence of excessive turbulence. Further, some continuous monitoring device for adequate hood performance should be present and should be checked before each hood is used. If inadequate hood performance is suspected, it should be established that the hood is performing adequately before it is used. Call your building administrator to report inoperable hoods.
3. Except when adjustments of apparatus within the hood are being made, the hood should be kept closed: vertical sashes down and horizontal sashes closed. Sliding sashes should not be removed from horizontal sliding-sash hoods. Keeping the face opening of the hood small improves the overall performance of the hood.
4. The airflow pattern, and thus the performance of a hood, depends on such factors as placement of equipment in the hood, room drafts from open doors or windows, persons walking by, or even the presence of the user in front of the hood. For example, the placement of equipment in the hood can have a dramatic effect on its performance. Moving an apparatus 5-10 cm back from the front edge into the hood can reduce the vapor concentration at the user's face by 90%.
5. Hoods are not intended primarily for storage of chemicals. Materials stored in them should be kept to a minimum. Stored chemicals should not block vents or alter airflow patterns. Whenever practical, chemicals should be moved from hoods into cabinets for storage.
6. Solid objects and materials (such as paper) should not be permitted to enter the exhaust ducts of hoods as they can lodge in the ducts or fans and adversely affect their operation.
7. An emergency plan should always be prepared for the event of ventilation failure (power failure, for example) or other unexpected occurrence such as fire or explosion in the hood.

Personal Protective Equipment

Lab workers must, at a minimum, wear lab coats and safety glasses in the laboratory. Additional protective equipment is required when working with chemicals. Shorts and sandals may not be worn into the lab even under a lab coat
Personal protective devices are to be used only where engineering and administrative controls cannot be used or made adequate, or while controls are being instituted.
Engineering and administrative controls to reduce or eliminate exposures to hazardous chemicals include:

• substitution of a less hazardous substance
• substitution of less hazardous equipment or process (e.g., safety cans for glass bottles)
• isolation of the operator or the process
• local and general ventilation (use of fume hoods)
• hazard education
• job rotation

The sds and University Standard Operating Procedure will list the personal protective equipment recommended for use with the chemical. The sds addresses "worst case" conditions. Therefore, not all of the equipment shown may be needed for a specific job.
The employer must provide appropriate personal protective equipment to employees.

Eye Protection

Eye and face protection must be worn whenever its use will reduce or eliminate injury. Eye protection must be worn in the laboratory whenever chemicals are in use.
The need for adequate eye protection is fundamental to the use of chemicals, including housekeeping materials such as wax strippers, detergent and toilet bowl cleaners, and operations such as grinding, drilling, sawing with power tools. Eye protection, and at times face protection, is required wherever the potential for eye injury exists. Areas where eye protection must be worn are laboratories, glass cleaning and glassblowing shops, and machine shops or any area where active or automated work with chemicals is conducted. Eye protection is required for all personnel and visitors in these areas. No personnel may enter laboratories where chemicals are being handled or automated processes are in operation without eye protection and a lab coat.
Ordinary (street) prescription glasses do not provide adequate protection. (Contrary to popular opinion these glasses cannot pass the rigorous test for industrial safety glasses.) Adequate safety glasses must meet the requirements of the standard Practice for Occupational and Educational Eye and Face Protection (ANSI Z.87.1 1989) and must be equipped with side shields.
Safety glasses with side shields do not provide adequate protection from splashes, therefore, when the potential for a splash hazard exists other eye protection and/or face protection must be worn.
Splash goggles (acid goggles) with splash proof sides or a face shield must be used when protection from a chemical splash is needed.
Face shields afford protection to the face and neck. Face shields must be worn if there is an explosion or implosion (pressure or vacuum) hazard and when transferring cryogenic liquids.
Special eye protection is available for protection against laser, ultraviolet (UV), welding and brazing, or intense light sources.
Managers, supervisors, and principal investigators should refer to the appropriate University Standard Operating Procedure to determine the type(s) of eye and/or face protection necessary.
Eye protection must be made available to employees, students and visitors, at no cost to them, when the potential for eye injury exists.
If you have any questions regarding the selection of appropriate face protection, call Environmental Health and Radiation Safety at 215-898-4453.

Lab Coats

Lab workers must wear lab coats while in a lab where chemicals are being handled. Lab coats should not be worn outside of the lab. The employer (principal investigator) must provide lab coats and lab coat laundering services at no cost to all employees who work in the lab. Shorts and sandals should not be worn under a lab coat.  Lab coats should be 100% cotton.  Researchers who work with liquid pyrophorics and perform manual transfers should wear fire resistant lab coats.

Glove Selection

Disposable nitrile gloves provide adequate protection against accidental hand contact with small quantities of most laboratory chemicals. These gloves provide a non chemical resistant barrier between the worker's hand the reagent. Lab workers who contaminate their gloves should immediately removed them, wash their hands and don new gloves. Gloves should not be worn outside of the lab. Latex gloves are not recommended for laboratory use.
Lab workers should contact EHRS for advice on chemical resistant glove selection when direct or prolonged contact with hazardous chemicals is anticipated. The selection of the proper glove requires knowledge of the health and physical hazards of the chemical that is used; familiarity with the glove manufacturer's test data (permeation rate and breakthrough time) and the length of the hand exposure. Lab workers should not select chemical resistant gloves based on data from generic selection charts.

Use of Respirators

If your work requires the use of a respirator, you must receive special training from EHRS. Do not use respiratory protective equipment until you have received proper training.
Respirators are designed to protect only against specific types of substances and in certain concentration ranges, depending on the type of equipment used. Never use a respirator unless you have been assigned one and have been trained and fit tested by the Office of Environmental Health and Radiation Safety.
Respirator selection is based on the hazard and the protection factor required.
Types of respiratory protective equipment include:

• particle-removing air purifying respirators (N95, N100)
• gas and vapor-removing air purifying respirators
• air supplied respirators

You should familiarize yourself with the limitations of each type of respiratory protective equipment used and the signals for respirator failure (odor breakthrough, filter clogging, etc.).
Respirators are not to be used except in conjunction with a written respiratory protection program.

Protection of the Body (other than the hands)

Skin and body contact should not occur during routine lab operations that involve small quantities of laboratory chemicals. Any lab activity that is anticipated to result in body contact must be evaluated by EHRS.
Lab staff must wear lab coats when handling hazardous chemicals to prevent against body contact that may result from accidental spills and splashes.
Chemical protective clothing in the form of disposable work suits should be provided for the rare instances where body contact is anticipated or when extremely toxic chemicals are handled. Special attention must be given to sealing all openings in the clothing. Tape can be used for this purpose. Caps should be worn to protect hair from contamination. Selection of the protective clothing shall be made by EHRS.

Designated Areas

All locations within the laboratory where acutely toxic, carcinogenic, or reproductive hazards are handled should be demarcated with designated area caution tape. Preprinted tape is available from EHRS (see Appendix G), the Cell Center or the Chemistry stockroom. Alternately the lab worker may write designated area on yellow tape and use that. Areas that should be designated include all fume hoods, sinks and bench tops where the acutely toxic, carcinogenic, or reproductive hazards are handled. The tape should be used in the same manner as radiation caution tape; the lab worker may designate an area only during the time the chemical is used and then remove it or may permanently designate an area and leave the tape in place.