VI. HANDLING AND USE OF CHEMICALS: LABORATORY OPERATIONS

deliberately drive on the wrong side of the road, or through red lights and stop signs, nor would

most of us deliberately violate similar common sense rules governing practices which would lead

to ill health. It is impossible to achieve absolute safety, but in the presence of hazards, it is only

reasonable to take those steps which will efficiently and effectively reduce the risks to acceptable

levels. Laboratory workers should follow ALARA principles (using the parlance of radiation

safety) and reduce the risks to a level as low as is reasonably achievable.

Laboratory operations are so varied that it would be totally impractical to attempt to exhaustively cover the topic. There are, however, some basic considerations which should be used

to enhance the safety of laboratory operations. Some of these are common sense and some have

been made mandatory by regulatory requirements, because some safety-related practices are too

important to be left to choice. Prior to addressing specific topics, the following list of simple rules,

if followed religiously, should dramatically reduce the number of laboratory accidents, or would

diminish the consequences of those that do occur.

1. Plan the work carefully. At the beginning of an extended project, formally analyze the

proposed program for possible hazards and consider the consequences of possible

failures or errors. Ask a colleague to review the hazard analysis with you. Being too close

to a subject often leads to overlooking potential problems. Unfortunately, even with the

best plans, eventualities will exist which no one thinks of, and these are just the ones

which may result in accidents.

2. Make sure the right equipment is available and in good condition. All too often, makeshift

equipment or deteriorated equipment is the cause of an accident. Rarely is it worth the

risk to take chances. Most persons with more than a few years of experience can think

of a number of examples where this has proven true, sometimes tragically.

3. Make sure all systems are assembled in a stable and solid manner, making sure that

accommodations for the specific limitations or failure modes of the individual components

are factored into the operation of the total system.

4. If the release of a toxic or hazardous substance may occur, the work should be done in

a fume hood appropriately designed for the operation. Use the fume hood so as to

maximize its effectiveness.

5. U se an explosion shield, other protective enclosures, and/or personal protection equ i p ment such as goggles. and a face mask if there is a possibility of a violent reaction. Do

not overlook the possibility that scaling up a process will change the safe operating

parameters.

6. Chemicals should be handled carefully at all times, using appropriate containers and

carrying devices. Open containers should be closed after use, and unneeded reagents

should be returned to secure storage.

7. Do not hurry unnecessarily or compromise on safety. Take the time to do things properly,

e.g., label temporary containers as they are employed. Many accidents are due to

unnecessary haste or the use of “shortcuts.”

8. Follow good safety practices with electrical circuits and equipment. Avoid use of extension cords, multiple plugs, and devices to defeat the need to use three-wire connectors.

9. Avoid working alone if possible. As a minimum, a second person should be aware of an

individual working alone in a laboratory and definite arrangements should be made for

periodic checks. Excessively long working hours increase the likelihood of mistakes due

to fatigue.

10. Follow good housekeeping practices. Maintain the work area in an orderly fashion.

11. Do not set up equipment so as to block means of egress from the work area. Consider the

activities of others sharing the facility with you in establishing your own work space.

12. Conscientiously use any required protective equipment and wear appropriate clothing.



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13. Make sure that you are familiar with and conscientiously follow all safety and emergency

procedures.

14. The work area in a laboratory is not a restaurant or a place to socialize. Coffee and meal

breaks should be taken at a desk outside the active work area or in a lounge set aside for

the purpose. Especially, do not use laboratory beakers for beverages.

15. Anyone indulging in horseplay or practical jokes within a laboratory should be excluded

from the facility.

16. Never work while under the influence of drugs or alcohol nor allow others to do so.



REFERENCES

1.



Safety in Academic Laboratories, 5th ed., American Chemical Society, Washington, D.C. 1991.



2.



Prudent Practices in the Laboratory, Handling and Disposal of Chemicals, National Academy Press,

Washington, D.C., 1995.



A. Physical Laboratory Conditions

Many of the points to be made in this section were alluded to in Chapter 3, where the factors

that should be considered in laboratory design were discussed. If the layout of the laboratory

is similar to that of the standard laboratory module shown in Figure 3.1, and repeated on the next

page as Figure 4.6, many safety practices which depend upon the phy sical configuration of the

facility will almost automatically follow. However, in many cases, laboratories are often placed

in structures originally designed for other purposes and ill adapted for the intended use. Even

in this latter case, safety can be significantly enhanced by following a few straightforward

guidelines as closely as the available space permits.

1. Organization of the Laboratory

The basic premise in laying out the interior design of a laboratory facility or allocating space

for the various activities within an existing facility is to separate areas of high risk from those of

low risk as much as possible, and to place high-risk operations where there will be the least traffic

and the least probability of blocking escape from the laboratory in case of an accident. Escape

routes should, wherever possible, lead from high-to low-risk areas. A high-risk component may

not always be obvious. For example, storage of chemicals in appropriate cabinets does not

represent a high risk under most circumstances, but if left open, a flammable material storage

cabinet along a path of egress can become a major danger if the liquids stored inside become

involved in a fire. If the configuration of the laboratory permits, the laboratory furniture should

be selected to permit two alternative evacuation paths from any point in the room. One of these,

constituting a secondary escape path, may not necessarily lead directly from a high- to a lowhazard area, but even a poor alternative is better than none at all.

Fume hoods are intended to be used to house activities that should not be done on an open

bench because of the potential hazard which the activities represent, usually the generation of

noxious fumes. The ability of fume hoods to capture and retain fumes generated within them is

especially vulnerable to air movement, either due to traffic or other factors such as the location

of air system ducts, windows, doors, or fans. Clearly, they should be located, as in the standard

laboratory module, in a remote portion of the laboratory selected for low traffic and minimal air

movement. Other fume generating apparatus, such as Kjeldahl units, should also be placed in

out of the way places where errant air motion will not result in dispersion of the fumes generated

into more heavily occupied areas of the room. A point that needs to be considered is the work

habits of laboratory employees. Data on the possible health effects of long-term exposures to

the vapors from most laboratory chemicals is relatively scant, although there are beginning to



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Figure 4.6



Standard Laboratory Module.



be more epidemiological data for various modes of exposures, indicating some general problems.

There are very little data on the synergistic effects of combinations of general laboratory

chemicals. It is known, however, that the sensitivity of individuals to materials varies widely.

Again, in the spirit of ALARA, as applied to chemical usage, when evidence to the contrary is

missing, a conservative approach is recommended to limit exposures. Research personnel

should spend no more time than is essential to the work in progress in areas where

the generation and concentration of chemical vapors is likely to be higher (although certainly

not above the PEL or action levels established by OSHA), as compared to other spaces in the

facility. The practice of allowing or requiring laboratory technicians to have desks in the work

area either for convenience or so that they can keep an eye on the work in progress should be

discontinued for both health and safety reasons. The standard module provides for this oversight

safely by making the barrier between the desk area and the laboratory proper transparent.

The location of the various items of equipment in a laboratory should depend upon a number

of factors, such as frequency of use, distances to be traveled, and the need to transport chemicals

to and from the primary work location and the storage areas. The distances traveled to and from

the most heavily used apparatus should be minimized, as should the frequency and distances

involved in the use of chemical reagents. Specialized work, such as the use of radioactive

materials, should be isolated from the other activities in the laboratory, especially if only some

of the laboratory's employees are involved in the activity while others are not. Any equipment

which generates fumes or vapors, but not of the character or concentration that would mandate

use of a fume hood, should take into account the air distribution patterns within the room so that

the dispersion into heavily occupied areas would be minimized.

Dangerous apparatus should be placed in areas in which protection can be afforded to the

maximum number of laboratory employees. For example, a temporary glass system containing a

highly reactive material under pressure might be located to one side of the laboratory with

explosive barriers placed on either side of the system so that if the system did rupture, the flying

particles of glass would be directed toward a normally unoccupied area of the laboratory. Of

course, if the probability of an explosion is significant, instead of being only a comparatively

remote possibility, the work should take place in a laboratory built with the proper explosion



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venting and explosion-resistant barriers.

Safety showers and deluge showers should be conveniently located within the facility so

that the approach to them is uncomplicated and unlikely to be blocked. They should also be

located close to the primary entrance to the laboratory so that persons rendering assistance to

an injured individual should not have to enter the laboratory any farther than nec e s s a r y , t o

reduce the possibility of having to enter a contaminated area. Note that in the standard laboratory

module, both shower and eyewash station are located at the end of the workbench closest to the

entrance and immediately adjacent to a secondary entrance. Also note that the portable fire

extinguisher is on the wall behind the workbench, near the fume hood and close to the

combination eyewash station and deluge shower, nearest the areas where it might be needed and

useful. A first aid kit should be maintained in the desk area.

2. Eating, Studying, and Other Social Activities

Unless provision is made for acceptable alternatives or extremely tight discipline is maintained

in the laboratory, it should be recognized that the work area of the laboratory will be used for

eating, studying, and social activities. Such activities, however, should not take place, and as

a minimum the laboratory should be clearly marked where these activities will not be allowed

under any circumstances. The NRC, for example, considers failure to prevent eating, drinking,

and smoking in the active work area sufficient cause for a citation. In recognition of the need to

control these activities, the standard laboratory module does provide a convenient and

acceptable location within the laboratory for eating, record and lab book maintenance, studying,

and social activities by placing a desk space immediately inside the laboratory facility, separated

from the rest of the laboratory by a partition. The location of this office class space also provides

direct access to the exit way corridor and to the reminder of the building without having to reenter

the laboratory in the event of an emergency. The upper half of the partition separating the

laboratory and desk spaces in the laboratory module is intended to be transparent, made either

of tempered safety glass or a plastic material such as LexanTM. This makes it possible to keep an

eye on laboratory operations while taking a coffee or lunch break in safety, or to perform any

other desired activity without interfering with laboratory operations or being disturbed by others

still in the laboratory. Since the laboratory, in most instances, should be at a modest negative

pressure with respect to the corridor, the passage of vapors from the laboratory into the desk

area should be inhibited, reducing the routine exposure to the laboratory atmosphere to those

at their desks significantly. The low speed of the air through the door, on the order of 10 to 20

fpm, will still make it possible for traffic through the door to allow a much reduced amount of

laboratory odors into the office compartment. The two doors in sequence also serve an additional

safety function, representing a simplified air lock, separating the corridor from the laboratory, thus

adding some stability to the HVAC demands within the room. If they are closed following an

evacuation, they would provide an additional barrier to any fire or noxious gases spreading from

the laboratory to the remainder of the building.

3. Maintenance

Topics generally overlooked in laboratory safety are safety factors involved in providing

needed maintenance and custodial services. Access to equipment needing service must be provided to service personnel under conditions which make it possible for them to perform their work

safely. Generally, equipment maintenance in the laboratory by support personnel should be

coordinated by an individual who is familiar with current and recent research programs, and can

advise the workers who arrive on the scene of possible risks in handling the various components.

An example is maintenance on fume hood exhaust fans. Instances are known of workers servicing

fume hood exhausts who suffered severe reactions to contaminants on the equipment and the

roof in the vicinity of the exhaust duct, even though the hood was not in use at the time. It is not

enough to warn the maintenance department upon the initial request for services. Direct

information needs to be provided to the service persons on the scene. Some materials can remain



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a problem for extended periods of time. In such cases, the workers need to be protected while

doing the work, using appropriate items of protective clothing such as gloves, respirators,

coveralls, and goggles or full-face respirators, depending upon the level of risk. The levels will

depend upon the contaminants that might exist due to work in the laboratory, and these risks

should be evaluated conservatively to enhance safety of the workers.

Where fume hood exhausts are brought to the roof through individual ducts, the area in which

maintenance is needed may be surrounded by exhaust ducts still in use, since in most cases it

is impractical to shut off operations for an entire building or even a significant portion of one,

because it is too disruptive to the research programs. Therefore, it is probably desirable to have

a standard personnel protective equipment package for the maintenance workers to use,

consisting of half- or full-face respirators providing protection against solvents, particulates, and

inorganic acids, chemically resistant coveralls, and gloves selected to provide a broad spectrum

of protection against chemicals. Requiring personnel to wear these may appear to be excessively

cautious but, as noted earlier, there have been instances where unanticipated severe and longlasting health effects have occurred. Not all employees who work on the roof of a chemistry

building may be employees of the organization. Outside contractors also are used to do a variety

of maintenance duties and, under the hazard communication standard, they must be apprized of

the risks to which they might be exposed. The mix of materials exhausted through ducts is

typically so complex that meeting this requirement is difficult, if not impossible. Recommending

to them to wear equivalent protection should fulfill the spirit of the standard. Unfortunately,

maintenance personnel may scoff at the need to wear protective equipment, or alternatively, be

so fearful of exposure that they may refuse to perform the needed task. It is the responsibility

of the organization to provide sufficient indoctrination and enforcement of their personnel

protection policies that both of these eventualities can be avoided.

Fume hood maintenance is one of the more active areas in which maintenance personnel have

concerns and where both support and laboratory personnel need to assume responsibility for

seeing that the work is properly coordinated. Some simple suggestions that have been found

useful are to ensure that each exhaust duct on the roof is properly labeled with the room location

of the hood itself. Workers have been known to turn off power to motors on hoods in active use.

Where hoods are dedicated to special uses which represent unusual hazards, such as radioactive

materials, perchloric acid, exceptionally toxic gases, or any other especially unusual risk, the duct

should also be labeled with the application involved or a color code employed to identify these

unusual risks. The latter program would alert maintenance personnel to definitely contact the

laboratory from which the duct came before working in the vicinity of the duct. Power to the

motors on the roof should also be provided in such a way as to ensure that the workers on the

roof can completely control the circuits while working to avoid accidental activation of the circuits

from the laboratory. However, should the exhaust motor be turned off by maintenance workers

without prior notification of laboratory personnel, an alarm should sound in the laboratory

warning that the hood is not functional. A tagging and lock-out procedure should also be

employed during the maintenance operation.

Once hoods are removed from service to perform maintenance, they should not be returned

to use until it is verified that they are performing according to required standards. It is easy to

erroneously wire a three-phase motor so that the fan rotates opposite to the desired direction.

Belts may need to be tightened or a pulley size changed to achieve the proper face velocity.

Fume hoods have been used to illustrate some of the problems that can arise from lack of

coordination of maintenance and laboratory personnel, but there are many other possible

problems. Explosions can occur if gas service is turned off without everyone being aware of it

and they leave gas jets open, flooding a facility with gas when service is restored. St ills can

overheat if condenser water supplies are interrupted. Electrical service to an area should be

discontinued and restored only with full prior notification to all persons that might be affected.

Today, with the large amount of computer automation being used, interrupting the power to



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