California Code of Regulations › Title 8 - Industrial Relations › Division 1 - Department of Industrial Relations › Chapter 4 - Division of Industrial Safety › Subchapter 7 - General Industry Safety Orders › Group 16 - Control of Hazardous Substances › Article 109 - Hazardous Substances and Processes › Appendix A - National Research Council Recommendations Concerning Chemical Hygiene in Laboratories (Non-Mandatory)

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
Table of Contents
Foreword
Corresponding Sections of the Regulation and This
						  Appendix
A. General Principles
1. Minimize all Chemical Exposures
2. Avoid Underestimation of Risk
3. Provide Adequate Ventilation
4. Institute Chemical Hygiene Program
5. Observe the exposure limits and TLV's
B. Responsibilities
1. Chief Executive Officer
2. Supervisor of Administrative Unit
3. Chemical Hygiene Officer
4. Laboratory Supervisor
5. Project Director
6. Laboratory Worker
C. The Laboratory Facility
1. Design
2. Maintenance
3. Usage
4. Ventilation
D. Components of the Chemical Hygiene Plan
1. Basic Rules and Procedures
2. Chemical Procurement, Distribution, and
						  Storage
3. Environmental Monitoring
4. Housekeeping, Maintenance and Inspections
5. Medical Program
6. Personal Protective Apparel and Equipment
7. Records
8. Signs and Labels
9. Spills and Accidents
10. Training and Information
11. Waste Disposal
E. General Procedures for Working With Chemicals
1. General Rules for all Laboratory Work with
						  Chemicals
2. Allergens and Embryotoxins
3. Chemicals of Moderate Chronic or High Acute
						  Toxicity
4. Chemicals of High Chronic Toxicity
5. Animal Work with Chemicals of High Chronic
						  Toxicity
F. Safety Recommendations
G. Safety Data Sheets
Foreword
As guidance for each employer's development of an
						  appropriate laboratory Chemical Hygiene Plan, the following non-mandatory
						  recommendations are provided. They were extracted from "Prudent Practices for
						  Handling Hazardous Chemicals in Laboratories" (referred to below as "Prudent
						  Practices"), which was published in 1981 by the National Research Council and
						  is available from the National Academy Press, 2101 Constitution Ave., NW.,
						  Washington DC 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 will modify any requirements of
						  the laboratory regulation. This Appendix merely presents pertinent
						  recommendations from "Prudent Practices," organized into a form convenient for
						  quick reference during development and application of a Chemical Hygiene Plan.
						  Users of this appendix should consult "Prudent Practices" for a more extended
						  presentation and justification for each recommendation.
"Prudent Practices" deals with both safety and chemical
						  hazards while the laboratory regulation is concerned primarily with chemical
						  hazards. Therefore, only those recommendations directed primarily toward
						  control of toxic exposures are cited in this appendix, with the term "chemical
						  hygiene" being substituted for the word "safety." However, since conditions
						  producing or threatening physical injury often pose toxic risks as well, page
						  references concerning major categories of safety hazards in the laboratory are
						  given in section F.
The recommendations from "Prudent Practices" have been
						  paraphrased, combined, or otherwise reorganized, and headings have been added.
						  However, their sense has not been changed.
Corresponding Sections of the Regulation and this
						  Appendix
The following table is given for the convenience of
						  those who are developing a Chemical Hygiene Plan which will satisfy the
						  requirements of subsection
						  5191(e). It
						  indicates those sections of this appendix which are most pertinent to each of
						  the sections of subsection
						  5191(e) and
						  related paragraphs.
Paragraph and topic in
									 laboratory standard
Relevant appendix
									 section
(e) (3) (A) Standard operating procedures for
								  handling toxic chemicals.
C, D, E
(e) (3) (B) Criteria to be used for
								  implementation of measures to reduce exposures.
D
(e) (3) (C) Fume hood
								  performance
C4b
(e) (3) (D) Employee information and training
								  (including emergency procedures).
D10, D9
(e) (3) (E) Requirements for prior approval of
								  laboratory activities.
E2b, E4b
(e) (3) (F) Medical consultation and medical
								  examinations.
D5, E4f
(e) (3) (G) Chemical hygiene
								  responsibilities.
B
(e) (3) (H) Special precautions for work with
								  particularly hazardous substances.
E2, E3, E4
In this appendix, those recommendations directed
						  primarily at administrators and supervisors are given in sections A - D. Those
						  recommendations of primary concern to employees who are actually handling
						  laboratory chemicals are given in section E. (Reference to page numbers in
						  "Prudent Practices" are given in parentheses.)
A. General Principles for Work with Laboratory
						  Chemicals
In addition to the more detailed recommendations listed
						  below in sections B-E, "Prudent Practices" expresses certain general
						  principles, including the following:
1. It is prudent to minimize all chemical exposures.
						  Because few laboratory chemicals are without hazards, general precautions for
						  handling all laboratory chemicals should be adopted, rather than specific
						  guidelines for particular chemicals (2,10). Skin contact with chemicals should
						  be avoided as a cardinal rule (198).
2. 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
						  (10, 37, 38). One should assume that any mixture will be more toxic than its
						  most toxic component (30, 103) and that all substances of unknown toxicity are
						  toxic (3, 34).
3. Provide adequate ventilation. The best way to
						  prevent exposure to airborne substances is to prevent their escape into the
						  working atmosphere by use of hoods and other ventilation devices (32,
						  198).
4. Institute a chemical hygiene program. A mandatory
						  chemical hygiene program designed to minimize exposures is needed; it should be
						  a regular, continuing effort, not merely a standby or short-term activity
						  (6,11). Its recommendations should be followed in academic teaching
						  laboratories as well as by full-time laboratory workers (13).
5. Observe the exposure limits and TLVs. The Exposure
						  limits of Cal/OSHA and the Threshold Limit Values of the American Conference of
						  Governmental Industrial Hygienists should not be exceeded (13).
B. Chemical Hygiene Responsibilities
Responsibility for chemical hygiene rests at all levels
						  (6, 11, 21) including the:
1. Chief executive officer, who has ultimate
						  responsibility for chemical hygiene within the institution and must, with other
						  administrators, provide continuing support for institutional chemical hygiene
						  (7, 11).
2. Supervisor of the department or other administrative
						  unit, who is responsible for chemical hygiene in that unit (7).
3. Chemical hygiene officers, whose appointment is
						  essential (7) and who must:
(a) Work with administrators and other employees to
						  develop and implement appropriate chemical hygiene policies and practices
						  (7);
(b) Monitor procurement, use, and disposal of chemicals
						  used in the lab (8).;
(c) See that appropriate audits are maintained
						  (8);
(d) Help project directors develop precautions and
						  adequate facilities (10);
(e) Know the current legal requirements concerning
						  regulated substances (50); and
(f) Seek ways to improve the chemical hygiene program
						  (8, 11).
4. Laboratory supervisor, who has overall
						  responsibility for chemical hygiene in the laboratory (21) including
						  responsibility to:
(a) Ensure that workers know and follow the chemical
						  hygiene rules, that protective equipment is available and in working order, and
						  that appropriate training has been provided (21, 22);
(b) Provide regular, formal chemical hygiene and
						  housekeeping inspections including routine inspections of emergency equipment
						  (21, 171);
(c) Know the current legal requirements concerning
						  regulated substances (50, 231);
(d) Determine the required levels of protective apparel
						  and equipment (156, 160, 162); and
(e) Ensure that facilities and training for use of any
						  material being ordered are adequate (215).
5. Project director or director of other specific
						  operation, who has primary responsibility for chemical hygiene procedures for
						  that operation (7).
6. Laboratory worker, who is responsible for:
(a) Planning and conducting each operation in
						  accordance with the institutional and chemical hygiene procedures (7, 21, 22,
						  230); and
(b) Developing good personal chemical hygiene habits
						  (22).
C. The Laboratory Facility
1. Design. The laboratory facility should have:
(a) An appropriate general ventilation system (see C4
						  below) with air intakes and exhausts located so as to avoid intake of
						  contaminated air (194);
(b) Adequate, well-ventilated stockrooms/storerooms
						  (218, 219).
(c) Laboratory hoods and sinks (12, 162):
(d) Other safety equipment including eyewash fountains
						  and drench showers (162, 169): and
(e) Arrangements for waste disposal (12, 240).
2. Maintenance. Chemical-hygiene-related equipment
						  (hoods, incinerator, etc.) should undergo continual appraisal and be modified
						  if inadequate (11, 12).
3. Usage. The work conducted (10) and its scale (12)
						  must be appropriate to the physical facilities available and, especially, to
						  the quality of ventilation (13).
4. Ventilation
(a) General laboratory ventilation.
This system should; Provide a source of air for
						  breathing and for input to local ventilation devices (199); it should not be
						  relied on for protection from toxic substances released into the laboratory
						  (198); ensure that laboratory air is continually replaced, preventing increase
						  of air concentrations of toxic substances during the working day (194); direct
						  air flow into the laboratory from non-laboratory areas and out to the exterior
						  of the building (194).
(b) Hoods. A laboratory hood with 2.5 linear feet of
						  hood space per person should be provided for every 2 workers if they spend most
						  of their time working with chemicals (199); each hood should have a continuous
						  monitoring device to allow convenient confirmation of adequate hood performance
						  before use (200, 209). If this is not possible, work with substances of unknown
						  toxicity should be avoided (13) or other types of local ventilation devices
						  should be provided (199). See pp. 201-206 for a discussion of hood design,
						  construction, and evaluation.
(c) Other local ventilation devices. Ventilated storage
						  cabinets, canopy hoods, snorkels, etc. should be provided as needed (199). Each
						  canopy hood and snorkel should have a separate exhaust duct (207).
(d) Special ventilation areas. Exhaust air from glove
						  boxes and isolation rooms should be passed through scrubbers or other treatment
						  before release into the regular exhaust system (208). Cold rooms and warm rooms
						  should have provisions for rapid escape and for escape in the event of
						  electrical failure (209);
(e) Modifications. Any alteration of the ventilation
						  system should be made only if thorough testing indicates that worker protection
						  from airborne toxic substances will continue to be adequate (12, 193,
						  204).
(f) Performance. Rate: 4-12 room air changes/hour is
						  normally adequate general ventilation if local exhaust systems such as hoods
						  are used as the primary method of control (194).
(g) Quality. General air flow should not be turbulent
						  and should be relatively uniform throughout the laboratory, with no high
						  velocity or static areas (194, 195); airflow into and within the hood should
						  not be excessively turbulent (200); hood face velocity should be adequate
						  (typically 60-100 lfm) (200, 204).
(h) Evaluation. Quality and quantity of ventilation
						  should be evaluated on installation (202), regularly monitored (at least every
						  3 months) (6, 12, 14, 195), and reevaluated whenever a change in local
						  ventilation devices is made (12, 195, 207). See pp 195-198 for methods of
						  evaluation and for calculation of estimated airborne contaminant
						  concentrations.
D. Components of the Chemical Hygiene Plan
1. Basic Rules and Procedures (Recommendations for
						  these are given in section E, below)
2. Chemical Procurement, Distribution, and
						  Storage
(a) Procurement. Before a substance is received,
						  information on proper handling, storage, and disposal should be known to those
						  who will be involved (215, 216). No container should be accepted without an
						  adequate identifying label (216). Preferably, all substances should be received
						  in a central location (216).
(b) Stockrooms/storerooms. Toxic substances should be
						  segregated in a well-identified area with local exhaust ventilation (221).
						  Chemicals which are highly toxic (227) or other chemicals whose containers have
						  been opened should be in unbreakable secondary containers (219). Stored
						  chemicals should be examined periodically (at least annually) for replacement,
						  deterioration, and container integrity (218-19).
Stockrooms/storerooms should not be used as preparation
						  or repackaging areas, should be open during normal working hours, and should be
						  controlled by one person (219).
(c) Distribution. When chemicals are hand carried, the
						  container should be placed in an outside container or bucket. Freight-only
						  elevators should be used if possible (223).
(d) Laboratory storage. Amounts permitted should be as
						  small as practical. Storage on bench tops and in hoods is inadvisable. Exposure
						  to heat or direct sunlight should be avoided. Periodic inventories should be
						  conducted, with unneeded items being discarded or returned to the
						  storeroom/stockroom (225-6, 229).
3. Environmental Monitoring.
Regular instrumental monitoring of airborne
						  concentrations is not usually justified or practical in laboratories but may be
						  appropriate when testing or redesigning hoods or other ventilation devices (12)
						  or when a highly toxic substance is stored or used regularly (e.g., 3
						  times/week) (13).
4. Housekeeping, Maintenance, and Inspections
(a) Cleaning. Floors should be cleaned regularly
						  (24).
(b) Inspections. Formal housekeeping and chemical
						  hygiene inspections should be held at least quarterly (6, 21) for units which
						  have frequent personnel changes and semiannually for others; informal
						  inspections should be continual (21).
(c) Maintenance. Eye wash fountains should be inspected
						  at intervals of not less than 3 months (6). Respirators for routine use should
						  be inspected periodically by the laboratory supervisor (169). Safety showers
						  should be tested routinely (169). Other safety equipment should be inspected
						  regularly, (e.g., every 3-6 months) (6, 24, 171). Procedures to prevent
						  restarting of out-of-service equipment should be established (25).
(d) Passageways. Stairways and hallways should not be
						  used as storage areas (24). Access to exits, emergency equipment, and utility
						  controls should never be blocked (24).
5. Medical Program
(a) Compliance with regulations. Regular medical
						  surveillance should be established to the extent required by regulations
						  (12).
(b) Routine surveillance. Anyone whose work involves
						  regular and frequent handling of toxicologically significant quantities of a
						  chemical should consult a qualified physician to determine on an individual
						  basis whether a regular schedule of medical surveillance is desirable (11,
						  50).
(c) First aid. Personnel trained in first aid should be
						  available during working hours and an emergency room with medical personnel
						  should be nearby (173). See pp. 176-178 for description of some emergency first
						  aid procedures.
6. Protective Apparel and Equipment. These should
						  include for each laboratory:
(a) Protective apparel compatible with the required
						  degree of protection for substances being handled (158-161);
(b) An easily accessible drench-type safety shower
						  (162, 169);
(c) An eyewash fountain (162);
(d) A fire extinguisher (162-164);
(e) Respiratory protection (164-9), fire alarm and
						  telephone for emergency use (162) should be available nearby; and
(f) Other items designated by the laboratory supervisor
						  (156, 160).
7. Records
(a) Accident records should be written and retained
						  (174).
(b) Chemical Hygiene Plan records should document that
						  the facilities and precautions were compatible with current knowledge and
						  regulations (7).
(c) Inventory and usage records for high-risk
						  substances should be kept as specified in sections E3e below.
(d) Medical records should be retained by the
						  institution in accordance with the requirements of state and federal
						  regulations (12).
8. Signs and Labels
Prominent signs and labels of the following types
						  should be posted:
(a) Emergency telephone numbers of emergency
						  personnel/facilities, supervisors, and laboratory workers (28);
(b) Identity labels, showing contents of containers
						  (including waste receptacles) and associated hazards (27, 48);
(c) Location signs for safety showers, eyewash
						  stations, other safety and first aid equipment, exits (27) and areas where food
						  and beverage consumption and storage are permitted (24); and
(d) Warnings at areas or equipment where special or
						  unusual hazards exist (27).
9. Spills and Accidents
(a) A written emergency plan should be established and
						  communicated to all personnel; it should include procedures for ventilation
						  failure (200), evacuation, medical care, reporting, and drills (172).
(b) There should be an alarm system to alert people in
						  all parts of the facility including isolation areas such as cold rooms
						  (172).
(c) A spill control policy should be developed and
						  should include consideration of prevention, containment, cleanup, and reporting
						  (175).
(d) All accidents or near accidents should be carefully
						  analyzed with the results distributed to all who might benefit (8, 28).
10. Information and Training Program
(a) Aim: To ensure that all individuals at risk are
						  adequately informed about the work in the laboratory, its risks, and what to do
						  if an accident occurs (5, 15).
(b) Emergency and Personal Protection Training: Every
						  laboratory worker should know the location and proper use of available
						  protective apparel and equipment (154, 169). Some of the full-time personnel of
						  the laboratory should be trained in the proper use of emergency equipment and
						  procedures (6). Such training as well as first aid instruction should be
						  available to (154) and encouraged for (176) everyone who might need it.
(c) Receiving and stockroom/storeroom personnel should
						  know about hazards, handling equipment, protective apparel, and relevant
						  regulations (217).
(d) Frequency of Training: The training and education
						  program should be a regular, continuing activity - not simply an annual
						  presentation (15).
(e) Literature/Consultation: Literature and consulting
						  advice concerning chemical hygiene should be readily available to laboratory
						  personnel, who should be encouraged to use these information resources
						  (14).
11. Waste Disposal Program.
(a) Aim: to ensure that minimal harm to people, other
						  organisms, and the environment will result from the disposal of waste
						  laboratory chemicals (5).
(b) Content (14, 232, 233, 240): The waste disposal
						  program should specify how waste is to be collected, segregated, stored, and
						  transported and include consideration of what materials can be incinerated.
						  Transport from the institution must be in accordance with DOT regulations
						  (244).
(c) Discarding Chemical Stocks: Unlabeled containers of
						  chemicals and solutions should undergo prompt disposal; if partially used, they
						  should not be opened (24, 27). Before a worker's employment in the laboratory
						  ends, chemicals for which that person was responsible should be discarded or
						  returned to storage (226).
(d) Frequency of Disposal: Waste should be removed from
						  laboratories to a central waste storage area at least once per week and from
						  the central waste storage area at regular intervals (14).
(e) Method of Disposal: Incineration in an
						  environmentally acceptable manner is the most practical disposal method for
						  combustible laboratory waste (14, 238, 241).
Indiscriminate disposal by pouring waste chemicals down
						  the drain (14, 231, 242) or adding them to mixed refuse for landfill burial is
						  unacceptable (14).
Hoods should not be used as a means of disposal for
						  volatile chemicals (40, 200).
Disposal by recycling (233, 243) or chemical
						  decontamination (40, 230) should be used when possible.
E. Basic Rules and Procedures for Working with
						  Chemicals.
The Chemical Hygiene Plan should require that
						  laboratory workers know and follow its rules and procedures. In addition to the
						  procedures of the sub programs mentioned above, these should include the rules
						  listed below.
1. General Rules
The following should be used for essentially all
						  laboratory work with chemicals:
(a) Accidents and spills - Eye Contact: Promptly flush
						  eyes with water for a prolonged period (15 minutes) and seek medical attention
						  (33, 172).
Ingestion: This is one route of entry for which
						  treatment depends on the type and amount of chemical involved. Seek medical
						  attention immediately.
Skin Contact: Promptly flush the affected area with
						  water (33, 172, 178). and remove any contaminated clothing (172, 178). If
						  symptoms persist after washing, seek medical attention (33).
Clean-up: Promptly clean up spills, using appropriate
						  protective apparel and equipment and proper disposal (24, 33). See pp., 233-237
						  for specific clean-up recommendations.
(b) Avoidance of "routine" exposure: Develop and
						  encourage safe habits (23); avoid unnecessary exposure to chemicals by any
						  route (23);
Do not smell or taste chemicals (32). Vent apparatus
						  which may discharge toxic chemicals (vacuum pumps, distillation columns, etc.)
						  into local exhaust devices (199).
Inspect gloves (157) and test glove boxes (208) before
						  use.
Do not allow release of toxic substances in cold rooms
						  and warm rooms, since these have contained recirculated atmospheres
						  (209).
(c) Choice of chemicals: Use only those chemicals for
						  which the quality of the available ventilation system is appropriate
						  (13).
(d) Eating, smoking, etc.: Avoid eating, drinking,
						  smoking, gum chewing, or application of cosmetics in areas where laboratory
						  chemicals are present (22, 24, 32, 40); wash hands before conducting these
						  activities (23, 24). Avoid storage, handling, or consumption of food or
						  beverages in storage areas, refrigerators, glassware or utensils which are also
						  used for laboratory operations (23, 24, 226).
(e) Equipment and glassware: Handle and store
						  laboratory glassware with care to avoid damage; do not use damaged glassware
						  (25). Use extra care with Dewar flasks and other evacuated glass apparatus;
						  shield or wrap them to contain chemicals and fragments should implosion occur
						  (25). Use equipment only for its designed purpose (23, 26).
(f) Exiting: Wash areas of exposed skin well before
						  leaving the laboratory (23).
(g) Horseplay: Avoid practical jokes or other behavior
						  which might confuse, startle or distract another worker (23).
(h) Mouth suction: Do not use mouth suction for
						  pipeting or starting a siphon (23, 32).
(i) Personal apparel: Confine long hair and loose
						  clothing (23, 158). Wear shoes at all times in the laboratory but do not wear
						  sandals, perforated shoes, or sneakers (158).
(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
						  (24).
(k) Personal protection: Assure that appropriate eye
						  protection (154-156) is worn by all persons, including visitors, where
						  chemicals are stored or handled (22, 23, 33, 154).
Wear appropriate gloves when the potential for contact
						  with toxic materials exists (157); inspect the gloves before each use, wash
						  them before removal, and replace them periodically (157). (A table of
						  resistance to chemicals of common glove materials is given p. 159).
Use appropriate (164-168) respiratory equipment when
						  air contaminant concentrations are not sufficiently restricted by engineering
						  controls (164-5), inspecting the respirator before use (169).
Use any other protective and emergency apparel and
						  equipment as appropriate (22, 157-162).
Avoid use of contact lenses in the laboratory unless
						  necessary; if they are used, inform supervisor so special precautions can be
						  taken (155).
Remove laboratory coats immediately on significant
						  contamination (161).
(
l
) Planning: Seek information and
						  advice about hazards (7), plan appropriate protective procedures, and plan
						  positioning of equipment before beginning any new operation (22, 23).
(m) Unattended operations: Leave lights on, place an
						  appropriate sign on the door, and provide for containment of toxic substances
						  in the event of failure of a utility service (such as cooling water) to an
						  unattended operation (27, 128).
(n) Use of hood: Use the hood for operations which
						  might result in release of toxic chemical vapors or dust (198-9).
As a rule of thumb, use a hood or other local
						  ventilation device when working with any appreciably volatile substance with a
						  TLV of less than 50 ppm (13).
Confirm adequate hood performance before use; keep hood
						  closed at all times except when adjustments within the hood are being made
						  (200); keep materials stored in hoods to a minimum and do not allow them to
						  block vents or air flow (200).
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"
						  (200).
(o) Vigilance: Be alert to unsafe conditions and see
						  that they are corrected when detected (22).
(p) Waste disposal: Assure that the plan for each
						  laboratory operation includes plans and training for waste disposal
						  (230).
Deposit chemical waste in appropriately labeled
						  receptacles and follow all other waste disposal procedures of the Chemical
						  Hygiene Plan (22, 24).
Do not discharge to the sewer concentrated acids or
						  bases (231); highly toxic, malodorous, or lachrymatory substances (231); or any
						  substances which might interfere with the biological activity of waste water
						  treatment plants, create fire or explosion hazards, cause structural damage or
						  obstruct flow (242).
(q) Working alone: Avoid working alone in a building;
						  do not work alone in a laboratory if the procedures being conducted are
						  hazardous (28).
2. Working with Allergens and Embryotoxins
(a) Allergens (examples: diazomethane, isocyanates,
						  bichromates): Wear suitable gloves to prevent hand contact with allergens or
						  substances of unknown allergenic activity (35).
(b) Embryotoxins (34-5) (examples: organomercurials,
						  lead compounds, formamide): If you are a woman of childbearing age, handle
						  these substances only in a hood whose satisfactory performance has been
						  confirmed, using appropriate protective apparel (especially gloves) to prevent
						  skin contact.
Review each use of these materials with the research
						  supervisor and review continuing uses annually or whenever a procedural change
						  is made.
Store these substances, properly labeled, in an
						  adequately ventilated area in an unbreakable secondary container.
Notify supervisors of all incidents of exposure or
						  spills; consult a qualified physician when appropriate.
3. Work with Chemicals of Moderate Chronic or High
						  Acute Toxicity
Examples: diisopropylfluorophosphate (41), hydrofluoric
						  acid (43), hydrogen cyanide (45).
Supplemental rules to be followed in addition to those
						  mentioned above (Procedure B of "Prudent Practices," pp. 39-41):
(a) Aim: To minimize exposure to these toxic substances
						  by any route using all reasonable precautions (39).
(b) Applicability: These precautions are appropriate
						  for substances with moderate chronic or high acute toxicity used in significant
						  quantities (39).
(c) Location: Use and store these substances only in
						  areas of restricted access with special warning signs (40, 229).
Always use a hood (previously evaluated to confirm
						  adequate performance with a face velocity of at least 60 linear feet per
						  minute) (40) or other containment device for procedures which may result in the
						  generation of aerosols or vapors containing the substance (39); trap released
						  vapors to prevent their discharge with the hood exhaust (40).
(d) Personal protection: Always avoid skin contact by
						  uses of gloves and long sleeves (and other protective apparel as appropriate)
						  (39). Always wash hands and arms immediately after working with these materials
						  (40).
(e) Records: Maintain records of the amounts of these
						  materials on hand, amounts used, and the manes of the workers involved (40,
						  229).
(f) Prevention of spills and accidents: Be prepared for
						  accidents and spills (41).
Ensure that at least 2 people are present at all times
						  if a compound in use is highly toxic or of unknown toxicity (39).
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
						  (40).
If a major spill occurs outside the hood, evacuate the
						  area; assure that cleanup personnel wear suitable protective apparel and
						  equipment (41).
(g) Waste: Thoroughly decontaminate or incinerate
						  contaminated clothing or shoes (41). If possible, chemically decontaminate by
						  chemical conversion (40).
Store contaminated waste in closed, suitably labeled,
						  impervious containers (for liquids, in glass or plastic bottles half-filled
						  with vermiculite) (40).
4. Work with Chemicals of High Chronic Toxicity
						  (Examples: dimethylmercury and nickel carbonyl (48), benzo-a-pyrene (51),
						  N-nitrosodiethylamine (54), other human carcinogens or substances with high
						  carcinogenic potency in animals (38).)
Further supplemental rules to be followed, in addition
						  to all these mentioned above, for work with substances of known high chronic
						  toxicity (in quantities above a few milligrams to a few grams, depending on the
						  substance) (47). (Procedure A of "Prudent Practices" pp, 47-50).
(a) Access: Conduct all transfers and work with these
						  substances in a "controlled area": a restricted access hood, glove box, or
						  portion of a lab, designated for use of highly toxic substances, for which all
						  people with access are aware of the substances being used and necessary
						  precautions (48).
(b) Approvals: Prepare a plan for use and disposal of
						  these materials and obtain the approval of the laboratory supervisor
						  (48).
(c) Non-contamination/Decontamination: Protect vacuum
						  pumps against contamination by scrubbers or HEPA filters and vent them into the
						  hood (49). Decontaminate vacuum pumps or other contaminated equipment,
						  including glassware, in the hood before removing them from the controlled area
						  (49, 50). Decontaminate the controlled area before normal work is resumed there
						  (50).
(d) Exiting: On leaving a controlled area, remove any
						  protective apparel (placing it in an appropriate, labeled container) and
						  thoroughly wash hands, forearms, face, and neck (49).
(e) Housekeeping: Use a wet mop or a vacuum cleaner
						  equipped with a HEPA filter instead of dry sweeping if the toxic substance was
						  a dry powder (50).
(f) Medical surveillance: If using toxicologically
						  significant quantities of such a substance on a regular basis (e.g., 3 times
						  per week), consult a qualified physician concerning desirability of regular
						  medical surveillance (50).
(g) Records: Keep accurate records of the amounts of
						  these substances stored (229) and used, the dates of use, and names of users
						  (48).
(h) Signs and labels: Assure that the controlled area
						  is conspicuously marked with warning and restricted access signs (49) and that
						  all containers of these substances are appropriately labeled with identity and
						  warning labels (48).
(i) Spills: Assure that contingency plans, equipment,
						  and materials to minimize exposures of people and property in case of accident
						  are available (233-4).
(j) Storage: Store containers of these chemicals only
						  in a ventilated, limited access (48, 227, 229) area in appropriately labeled,
						  unbreakable, chemically resistant, secondary containers (48, 229).
(k) Glove boxes: For a negative pressure glove box,
						  ventilation rate must be at least 2 volume changes/hour and pressure at least
						  0.5 inches of water (48). For a positive pressure glove box, thoroughly check
						  for leaks before each use (49). In either case, trap the exit gases or filter
						  them through a HEPA filter and then release them into the hood (49).
(
l
) Waste: Use chemical
						  decontamination whenever possible; ensure that containers of contaminated waste
						  (including washings from contaminated flasks) are transferred from the
						  controlled area in a secondary container under the supervision of authorized
						  personnel (49, 50, 233).
5. Animal Work with Chemicals of High Chronic
						  Toxicity
(a) Access: For large scale studies, special facilities
						  with restricted access are preferable (56).
(b) Administration of the toxic substance: When
						  possible, administer the substance by injection or gavage instead of in the
						  diet. If administration is in the diet, use a caging system under negative
						  pressure or under laminar air flow directed toward HEPA filters (56).
(c) Aerosol suppression: Devise procedures which
						  minimize formation and dispersal of contaminated aerosols, including those from
						  food, urine, and feces (e.g., use HEPA filtered vacuum equipment for cleaning,
						  moisten contaminated bedding before removal from the cage, mix diets in closed
						  containers in a hood) (55, 56).
(d) Personal protection: When working in the animal
						  room, wear plastic or rubber gloves, fully buttoned laboratory coat or jumpsuit
						  and, if needed because of incomplete suppression of aerosols, other apparel and
						  equipment (shoe and head coverings, respirator) (56).
(e) Waste disposal: Dispose of contaminated animal
						  tissues and excreta by incineration if the available incinerator can convert
						  the contaminant to non-toxic products (238); otherwise, package the waste
						  appropriately for burial in an EPA-approved site (239).
F. Safety Recommendations
The above recommendations from "Prudent Practices" do
						  not include those which are directed primarily toward prevention of physical
						  injury rather than toxic exposure. However, failure of precautions against
						  injury will often have the secondary effect of causing toxic exposures.
						  Therefore, we list below page references for recommendations concerning some of
						  the major categories of safety hazards which also have implications for
						  chemical hygiene:
1. Corrosive agents: (35-6)
2. Electrically powered laboratory apparatus:
						  (179-92)
3. Fires, explosions: (26, 57-74, 162-64, 174-5,
						  219-20, 226-7)
4. Low temperature procedures: (26, 88)
5. Pressurized and vacuum operations (including use of
						  compressed gas cylinders): (27, 75-101)
G. Safety Data Sheets
Safety data sheets are presented in "Prudent Practices"
						  for the chemicals listed below. (Asterisks denote that comprehensive safety
						  data sheets are provided).
*Acetyl peroxide (105)
*Acrolein (106)
*Acrylonitrile (107)
Ammonia (anhydrous) (91)
*Aniline (109)
*Benzene (110)
*Benzo[a]pyrene (112)
*Bis(chloromethyl) ether (113)
Boron trichloride (91)
Boron trifluoride (92)
Bromine (114)
*Tert-butyl hydroperoxide (148)
*Carbon disulfide (116)
Carbon monoxide (92)
*Carbon tetrachloride (118)
*Chlorine (119)
Chlorine trifluoride (94)
*Chloroform (121)
Chloromethane (93)
*Diethyl ether (122)
Diisopropyl fluorophosphate (41)
*Dimethylformamide (123)
*Dimethyl sulfate (125)
*Dioxane (126)
*Ethylene dibromide (128)
*Fluorine (95)
*Formaldehyde (130)
*Hydrazine and salts (132)
Hydrofluoric acid (43)
Hydrogen bromide (98)
Hydrogen chloride (98)
*Hydrogen cyanide (133)
*Hydrogen sulfide (135)
Mercury and compounds (52)
*Methanol (137)
*Morpholine (138)
*Nickel carbonyl (99)
*Nitrobenzene (139)
Nitrogen dioxide (100)
N-nitrosodiethylamine (54)
*Peracetic acid (141)
*Phenol (142)
*Phosgene (143)
*Pyridine (144)
*Sodium azide (145)
*Sodium cyanide (147)
Sulfur dioxide (101)
*Trichloroethylene (149)
*Vinyl choride (150)