OEH&S Chemical Safety Manual Chapter 4

GENERAL SAFETY AND INSPECTION PROGRAM

A. PRUDENT PRACTICES FOR HANDLING CHEMICALS

The following recommendations were extracted from "Prudent Practices for Handling Hazardous Chemicals in Laboratories" (referred to below as "Prudent Practices"), which was published in 1995 by the National Research Council and is available from the National Academy Press, 2101 Constitution Avenue NW, Washington D.C., 20418.

"Prudent Practices" is cited because of its wide distribution and acceptance, and because of its preparation by members of the laboratory community through the sponsorship of the National Research Council. However, none of the recommendations given here take precedence over any of the legal requirements of current legislation. This merely presents pertinent recommendations from "Prudent Practices" organized into a form convenient for quick reference during operation of a laboratory facility and during application of the Chemical Safety and Hazard Communication Program. Users should consult "Prudent Practices" for a more extended presentation and justification for each recommendation.

1. GENERAL PRINCIPLES FOR WORKING WITH LABORATORY CHEMICALS

a. Minimize All Chemical Exposures

Because few laboratory chemicals are without hazards, general precautions for handling all laboratory chemicals should be adopted, in addition to specific guidelines for chemicals that present particular hazards. Contacts with the chemical by inhalation, ingestion, or skin contact should be avoided.

b. Avoid Underestimation of Risk

Even for substances of no known significant hazard, exposure should be minimized. For work with substances which present special hazards, special precautions should be taken. One should assume that any mixture will be more toxic than its most toxic component and that all substances of unknown toxicity are potentially toxic.

c. Provide Adequate Ventilation

The best way to prevent exposure to airborne substances is to prevent their escape into the working atmosphere by use of proper hoods and other local ventilation devices. General dilutional ventilation is much less effective, and may contaminate other neighboring laboratories or offices if any recirculation of air occurs. UCSF laboratory areas are designed to avoid recirculation.

d. Adhere to the UCSF Chemical Safety and Hazard Communication Programs

This mandatory program is designed to minimize exposures; it should be a regular, continuing effort, not merely a standby or short-term activity. These recommendations should be carefully followed by students in academic teaching laboratories as well as by full-time laboratory workers.

e. Ascertain that Exposures Are as Low as Technically Feasible

It is now generally recognized that the current permissible exposure limits (PELs) based on the Threshold Limit Values (TLVs) established by the American Conference of Governmental Industrial Hygienists (ACGIH) are not adequate to protect all workers from adverse health effects. The PELs may be used simply as a rough index of relative toxicity, and are the currently, legally enforced limits, but the most prudent policy is to reduce exposures to the lowest level possible.

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2. BASIC RULES AND PROCEDURES FOR WORKING WITH CHEMICALS

The following General Rules are to be used for essentially all laboratory work with chemicals:

a. Accidents and Spills

(See Chapter 8 for Specific Procedures)

1. Eye Contact
   Promptly flush eyes with water for a prolonged period (15 minutes) and seek medical attention.
2. Ingestion
   Call Poison Control at 1-800-876-4766 or immediately go to the nearest emergency room.
3. Skin Contact
   Remove contaminated clothing and promptly flush the affected area with water for at least 15 minutes and remove any contaminated clothing. If symptoms persist after washing, seek medical attention.
4. Clean-Up
   Promptly clean-up spills, using appropriate protective apparel and equipment and dispose all waste materials generated during clean up properly.

b. Avoidance of Routine Exposure

1. Develop and encourage safety habits, avoid unnecessary exposure to chemicals by any route.
2. Do not smell or taste chemicals. Vent any apparatus which may discharge toxic chemicals (e.g., vacuum pumps, distillation columns) into local exhaust devices (e.g., fume hoods). Do not exhaust into building ventilation system.
3. Inspect gloves for tears or pinholes before use. Use appropriate gloves for the chemicals used.
4. Do not allow release of toxic substances in cold rooms and warm rooms, since these have contained re-circulated atmospheres.

c. Choice of Chemicals

Use the least toxic chemicals possible for the intended purpose. Use only those chemicals for which the quality of the available ventilation system is appropriate.

d. Eating, Drinking, Smoking, Applying Cosmetics

Eating, drinking, gum chewing, application of cosmetics, and manipulation of contact lenses is prohibited in areas where laboratory chemicals are present; wash hands before conducting these activities. Storage, handling, or consumption of food or beverages in storage areas, refrigerators, glassware or utensils which are also used for laboratory operations is prohibited.

e. Equipment and Glassware

Handle and store laboratory glassware with care to avoid damage; do not use damaged glassware. Use extra care with Dewar flasks and other evacuated glass apparatus; shield or wrap them to contain chemicals and fragments should implosion occur. Use equipment only for its designated purpose.

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f. Exiting

Practice good hygiene and wash areas of exposed skin well before leaving the laboratory.

g. Horseplay

Avoid practical jokes or other behavior which might confuse, startle, or distract another worker.

h. Mouth Suction

Do not use mouth suction for pipetting or starting a siphon - use mechanical pipetting devices.

i. Personal Apparel

Confine long hair and loose clothing. Wear closed-top shoes at all times in the laboratory. Shorts are not recommended for laboratory workers.

j. Personal Housekeeping

Keep the work area clean and uncluttered, with chemicals and equipment being properly labeled and stored; clean up the work area on completion of an operation or at the end of each day.

k. Personal Protection

1. Assure that appropriate eye protection is worn by all persons, including visitors, where chemicals are stored or handled.
2. Wear appropriate gloves when the potential for contact with toxic materials exists; inspect the gloves before each use, wash them before removal, and replace them periodically. Do not wear gloves outside laboratories.
3. Use any other protective and emergency apparel and equipment as appropriate.
4. Remove laboratory coats immediately upon significant contamination. (See Chapter 5 For Specific Information on appropriate Personal Protective Equipment (PPE)).

l. Planning

Seek information and advice about hazards, plan appropriate protective procedures, and plan positioning of equipment before beginning any new operation. Contact your DSA.

m. Unattended Operations

Leave lights on, place an appropriate sign on the door, and provide for containment of toxic substances in the event of the failure of a utility service (such as cooling water) to an unattended operation. Post your name and a phone number where you can be reached in case of an emergency.

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n. Use of Hood

1. Use the hood for operations which might result in the release of toxic chemical vapors or dust.
2. As a rule of thumb, use a hood or other local ventilation device when working with any appreciably volatile substance with a PEL or TLV of less than 50 PPM (check the MSDS for information).
3. Confirm adequate hood performance before use; keep materials stored in hoods to a minimum and do not allow them to block vents or air flow.
4. Leave the hood "on" when it is not in active use if toxic substances are stored in it or if it is uncertain whether adequate general laboratory ventilation will be maintained when it is "off." (See Chapter 5 for specific Information on Fume Hoods).

o. Vigilance

Be alert to unsafe conditions and see that they are corrected when detected or reported to your safety committee or supervisor

p. Waste Disposal

1. Deposit chemical waste in appropriately labeled receptacles and follow all other waste disposal procedures.
2. Do not discharge any hazardous materials into the sewer.
3. Do not evaporate chemicals in fume hoods as means of disposal.
4. Detailed Procedures for Chemical Waste Disposal are listed in Chapter 9.

q. Working Alone

Avoid working alone in a building; do not work alone in a laboratory if the procedures being conducted are hazardous.

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3. SPECIFIC PROCEDURES WITH SELECTED CLASSES OF HAZARDOUS CHEMICALS

In addition to the general laboratory procedures recommended for all chemicals, the following specific procedures are recommended as supplementary precautions.

a. Allergens

When working with known or suspected allergens (e.g., diazomethane, isocyanates, bichromates), wear suitable gloves to prevent skin contact.

b. Embryotoxins

1. Use substances such as lead compounds or formamide only in hoods, while wearing appropriate protective apparel (especially gloves) to prevent skin contact.
2. Store these substances, properly labeled, in an adequately ventilated area in an unbreakable secondary container.
3. Notify your supervisor of all incidents of exposure or spills immediately.

c. Chemicals of Moderate Chronic or High Acute Toxicity

1. Minimize exposure to these toxic substances (e.g., diisopropylfluorophosphate, hydrofluoric acid, hydrogen cyanide) by any route using all reasonable precautions.
2. Use and store these substances only in areas of restricted access with special warning signs.
3. Always use a hood for procedures which may result in the generation of aerosols or vapors of these substances.
4. Avoid skin contact by use of gloves and long sleeves (and other protective apparel as appropriate). Always wash hands and arms immediately after working with these materials.
5. Maintain records of the amounts of these materials on hand, amounts used, and the names of the workers involved.
6. Be prepared for accidents and spills.
7. Ensure that at least two people are present at all times if a compound in use is highly toxic or of unknown toxicity.
8. Store breakable containers of these substances in chemically resistant trays; also work and mount apparatus above such trays or cover work and storage surfaces with removable, absorbent, plastic-backed paper.
9. If a major spill occurs outside the hood, evacuate the area; assure that clean-up personnel wear suitable protective apparel and equipment.
10. Thoroughly decontaminate contaminated clothing or shoes. If possible, chemically decontaminate by chemical conversion. If you cannot decontaminate, package them for disposal as chemical waste.
11. Store contaminated waste in closed, suitably labeled, impervious containers.

d. Animal Work with Chemicals of High Chronic Toxicity

Contact OEH&S and Laboratory Animal Resource Center (LARC) for proper safety precautions in use of high chronic toxicity chemicals in animals.

B. INSPECTIONS

Environmental Health and Safety will conduct periodic (at least annually) inspections of all laboratories using chemicals. A report of findings and corrective actions, if any, will be sent to Principal Investigators. Principal Investigators are expected to respond promptly in writing to OEH&S describing actions which have been taken to mitigate the hazard. Follow-up inspections may be conducted. If necessary, a summary of all inspection results will be presented to the Chemical Safety Committee.

In addition to OEH&S, the San Francisco Department of Public Health also conducts regular (annual or biannual) inspections of the laboratories and other chemical storage and use areas.

A copy of the inspection checklist and description is included as Appendices D2-D4.

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