I had an interesting (and prolonged)
Twitversation
with
@SellaTheChemist (a well
known British chemist and populizer of all things Chemistry in Britain) yesterday
about laboratory gloves. It all started with my comment about a photo
accompanying a
@ChemistryWorld
post. The folks in the picture were using the old style bulb pipettes. They
were wearing safety glasses and lab coats, but not gloves, and I complained
about the lack of gloves in the stock photo.
Little did I know that in Britain, at least (but I suspect
that might extend further in the EU), there is a ‘controversy’ over
requirements to routinely wear lab gloves in the laboratory. I had never heard
of a controversy about this very common personal protective equipment, so the
conversation was a bit eye opening for me.
It became clear pretty quickly that Andrea Sella and I were
talking past each other because of some basic disagreements on lab safety. And,
to be sure, the 140 character limit of a Twitversation is more than a little
limiting. So I thought I would take to my bully pulpit and issue a manifesto on
lab gloves.
The Legal Standard
Here in the United States the basic legal requirement for
the use of hand protection in the workplace is derived from the basic PPE
Standard found in
29
CFR 1910.132. Paragraph (a) sums up the basic requirement nicely:
“Protective equipment, including
personal protective equipment for eyes, face, head, and extremities, protective
clothing, respiratory devices, and protective shields and barriers, shall be
provided, used, and maintained in a sanitary and reliable condition wherever it
is necessary by reason of hazards of processes or environment, chemical
hazards, radiological hazards, or mechanical irritants encountered in a
manner capable of causing injury or impairment in the function of any part of the
body through absorption, inhalation or physical contact.” [emphasis added]
The specific standard (
§1910.138)
for gloves is actually quite short. It describes the selection process for
gloves in paragraph (b):
“Employers shall base the selection
of the appropriate hand protection on an evaluation of the performance
characteristics of the hand protection relative to the task(s) to be performed,
conditions present, duration of use, and the hazards and potential hazards
identified.”
To get a better understanding of how the glove requirements
are enforced in a lab environment you have to turn to the standard for “Occupational
exposure to hazardous chemicals in laboratories.” (
§1910.1450).
Each lab is required to develop and maintain (annual updates) a Chemical
Hygiene Plan. Part of that plan is the requirement to outline the criteria that
“the employer will use to determine and implement control measures to reduce
employee exposure to hazardous chemicals including engineering controls, the
use of personal protective equipment and hygiene practices” {§1910.1450(e)(3)(ii)}.
That clearly does not require the use of lab gloves. OSHA
inspectors expect to see the routine use of lab gloves because of a couple of
statements seen in Appendix A to §1910.1450.
This appendix is technically ‘non-mandatory’, but deviations from what is
recommended typically draw official comments from inspectors that require
justification of the deviations. The guidelines in the appendix address the
development of the required Chemical Hygiene Plan and are based upon the
National Research Council’s (NRC) 2011 edition of “Prudent Practices in the
Laboratory: Handling and Management of Chemical Hazards.”
The first principal is to minimize all chemical exposures
and risks. A key component of that principal is explained this way:
“Because few laboratory chemicals
are without hazards, general precautions for handling all
laboratory chemicals should be adopted [emphasis added]. In addition to
these general guidelines, specific guidelines for chemicals that are used
frequently or are particularly hazardous should be adopted.”
This is further expanded upon in the discussion of Hierarchy
of Controls to avoid chemical exposures. There is the specific admonition to “not
allow laboratory chemicals [emphasis added] to come in contact with
skin” that precedes the discussion of glove selection. Both of these comments
in Appendix A are used to explain an inspector’s expectation that laboratory
gloves will be worn whenever chemicals are handled in the lab. Failure of a lab
to meet that expectation would need to be justified to an inspector during an
inspection or investigation.
Selection of Gloves
As a lab manager the proper selection of gloves for use in
the lab is a very challenging topic if there are a variety of chemicals in use
since there is no single glove that is appropriate for handing of all
chemicals. Since lab gloves are high-turnover PPE, cost is certainly an issue.
But other factors that must be taken into account include
• Ease of wear or dexterity issues;
• Chemical permeability;
• Chemical reactions; and
• Temperature resistance.
For most labs this is going to mean that there is a general
use lab glove that is used for most operations in the lab and then there will
be gloves that will be used for specific chemicals or lab operations. It is not
unusual to find the typical medical vinyl or latex ‘exam’ gloves to be used for
general lab work; they are readily available from most supply houses and are
relatively inexpensive when bought in case lots.
There are a number of glove compatibility guides available
on-line. I have used both the
Cole-Parmer and the
Ansel
guides, but there are a number of others available. A quick test of chemical
compatibility (but not permeability) is to place 10 mL of the chemical in question
in a finger of the glove and see if the chemical leaks through the glove. The
longer it takes to break through the better, but I would never use a glove with
a chemical if it did not take at least five minutes to break through (more on
that later).
Wearing of Gloves
The first thing that you have to remember about gloves is
that they are, by definition, not permeable. This means that liquids outside of
the glove do not get inside (the purpose of wearing the gloves). But it also
means that liquids inside the glove (think sweat) will stay inside the gloves.
For people whose hands sweat prolifically this can lead to medical problems
with the skin if gloves are not changed frequently. Some people use powdered
(typically baby powder) gloves to mitigate this issue, but I have found that
this can create contamination issues. I prefer to use cotton inspection gloves
inside of my lab gloves.
Gloves have to fit properly so that the wearer can still
accurately operate lab equipment. Nothing will stop people from wearing gloves
faster than not being able to do their job with the gloves on. Unless you are
able to hire a staff with all the same sized hands (good luck) this means that
you are going to have to have multiple sizes of each type of glove on hand. As
a lab manager one of the first things that I do with new personnel is to determine
which size gloves they need and update my stocking as necessary.
Generally speaking, gloves should be worn whenever open
containers of chemicals are being handled. This includes shipping and storage
containers, but also lab containers like beakers, flasks and the like. Once a
container is closed and checked to ensure that there is no chemical on the
outside of the container, then gloves are typically no longer required. For
chemicals that have a low quantity/concentration chemical hazard may require
gloves when handling closed containers that have been previously opened because
of the possibility of small quantity spills/contamination on the outside of the
bottle. This needs to be addressed in the chemical hygiene plan.
Finally there have to be clear limits on where gloves cannot
be worn. Part of a chemical hygiene plan is taking a detailed look at lab
operations to see where gloves must be worn and areas where they may not be
worn. Doors are a common problem; you don’t want people to manipulate door
handles with gloves on and then have someone without gloves manipulate the same
handle. If people routinely carry chemicals into or out of the lab and that
requires wearing gloves (product samples coming into a QA lab are a good case
in point) then an automatic opener or levered door handles should be
considered.
Computer keyboards are another concern. Gloves should never
be worn when using a strictly admin computer. Keyboards (or other controls) for
lab instruments make for more difficult rules. A detailed analysis of how the
equipment is used will determine if the controls are always or never operated
with gloves. Signage and training are keys to making this work.
Chemical Hygiene
The whole purpose of wearing gloves is not to wear gloves
but to stop skin contact with chemicals. They are not to be used in place of
good laboratory techniques that strive to keep chemicals IN their appropriate
containers and not on the outside of the containers. This means that anytime
chemicals get on the gloves they either need to be cleaned or disposed of. This
is an absolute necessity to prevent cross contamination, particularly of closed
containers that most people feel comfortable not wearing glove to carry from
one location to another.
Making the decision between the two is primarily a chemical
hygiene decision, but any lab manager who has had to live within a budget knows
that there are also financial considerations. For any chemical, however, that
comes with a medical hazard at low concentrations (for bio-accumulators for instance)
disposal is probably going to be the first choice.
To make this work, lab personnel are going to have to be
trained to look at their gloves after each time that they handle a chemical
container. That way they will have the best chance of properly identifying the
contaminating chemical and taking the appropriate action to decontaminate.
Remember the five minute break through standard that I
described earlier. This is where that comes into play. You can get away with
using a glove that will break through after five minutes if you have properly
trained your personnel to check their gloves after each time they handle a
chemical. It is important, however, to let your people know what chemicals do
have break through times with specific gloves so that they can be extra careful
with the handling of those gloves.
Staging Gloves
If you are going to require employees to wear and change
gloves you are going to have to ensure that they are readily available. If
people have to walk very far they are probably going to ‘forget’ to wear the
gloves. This is especially true for gloves that are for limited use with
specific high hazard chemicals. Those chemicals and their required gloves need
to be collocated in the lab.
Training
Training is the key to any successful Chemical Hygiene Plan
and that is especially critical for the proper use of gloves. Employees need
initial and periodic refresher training on the Chemical Hygiene plan, but I
have found that additional training on the proper use of gloves is usually
required. Job aids are especially helpful in areas where specific glove types
are to be used. Just as important, however, is a clear marking of areas where
gloves are not to be worn.
Formal, documented training, is important, but day-to-day
training and evaluation needs to be included in the training program. Every
time that the lab manager enters the lab, a short pause should be taken for a
general safety observation of the lab. Specific checks for cleanliness,
orderliness and PPE should be made each time the lab manager enters the lab
with other observation objectives being made on a routine (scheduled) basis.
Short comings need to be quickly addressed as both a matter of training (ensuring
that people know what and why safety requirements are in place) and discipline
(ensuring that people do what they know is required).
One technique that can be used to help people consider PPE
requirements in labs where non-routine chemicals and processes are used is to
require a listing of the PPE as part of the heading in the lab notebook that is
completed before the experiment is run. With this in place, lab notebook
reviews become another technique for reinforcing the PPE requirements, with
attention paid to both the ‘what’ and the ‘why’ of the requirements.
Moving Forward
A Chemical Hygiene Plan is required for all chemical labs in
the United States. A key component of that Plan is delineation of the use of
chemical gloves to protect lab employees from physical exposure to chemicals in
the lab. Consideration of the chemicals handled, the mode of handling and the
quantities handled all must be included in determining the requirements for
selecting and using gloves as personal protection equipment.
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