Appendix A to §1910.1450 -- National Research Council
Recommendations Concerning Chemical Hygiene in Laboratories
(Non-Mandatory)
Table of Contents
Foreword
Corresponding Sections of the Standard and This Appendix
A. General Principles
1. Minimize all Chemical Exposures
2. Avoid
Underestimation of Risk
3. Provide Adequate Ventilation
4. Institute a Chemical Hygiene Program
5. Observe the PELs and TLVs
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. Material 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 standard. This Appendix merely presents pertinent
recommendations from "Prudent Practices'', organized into a
form convenient for quick reference during operation of a
laboratory facility and 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 standard 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 Standard 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 paragraph (e) of the standard. It indicates those
sections of this appendix which are most pertinent to each of the
sections of paragraph (e) and related paragraphs.
TABLE/GRAPH OMITTED
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 PELs, TLVs. The Permissible Exposure Limits of
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 officer(s), 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 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 continuing appraisal and be
modified if inadequate (11, 12).
3. Usage. The work conducted (10) and its scale (12) must be
appropriate to the physicial 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
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 assure 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 assure 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.
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