Tuesday, November 10, 2015

The Chemical Gloves Controversy – A Manifesto

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 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.

1 comment:

Rajesh Kumar said...

Very important points regarding safety procedures. While dealing in chemicals, acids, etc. it is very important to wear goggles, gloves and other protective as it can be life saving. Safety signs can be used to inform the workers about the safety measures. Wonderful blog with good points. Thanks a lot.

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