Overview of IAQ Problems in Laboratories  

Biohazards
Learning about the chemicals in the lab
Proper ventilation
Proper personal protective equipment
Work practices to maintain good IAQ

Laboratories can be a possible source of hazardous chemicals and biological agents used in laboratory experiments. Biohazards, which include bacteria, fungi and viruses, are carried through the air, by person-to-person contact, or through exposure to infected substances, such as blood. The chemicals can include things like solvents, corrosives, reactives, compressed gases, and heavy metals that can evaporate and get into the air. For example in a high school chemistry class in Connecticut in 1986, 22 students and a teacher were exposed to mercury vapors while conducting an experiment. Over a third of those exposed had mercury levels in their urine above the acceptable level. A month later six of these people still had elevated mercury levels in their urine though they all returned to normal levels a month after the incident.¹ In addition to the chemicals used for experiments, there is also the risk of things like mercury exposure from broken thermometers, especially if they are not properly cleaned up using approved mercury cleanup kits.

Biohazards

Whether a laboratory is located in a school, healthcare facility or research institute, the precautions that are taken with biological hazards should be universal. When in doubt, all biological fluids and substances should be considered potentially infectious. One of the easiest ways to prevent biological contamination is to use personal protective equipment when needed, wash your hands, keep the laboratory clean and adhere to all laboratory rules and regulations. Other things to consider are the correct labeling of specimens and biological containers, and the proper management of needles and other sharp materials.

For more information regarding occupational exposure to blood or other potentially infectious materials, the Occupational Safety and Health Administration (OSHA) regulations for bloodborne pathogens can be found at: www.osha-slc.gov/OshStd_data/1910_1030.html and changes to these regulations can be found at: www.osha-slc.gov/needlesticks/index.html.

Learning About Chemicals in the Laboratory

Because of the health and safety hazards of chemicals used in labs, it is important to find out about the chemicals beforehand. You can request Material Safety Data Sheets (MSDS) from suppliers and manufacturers for products you have bought. In addition, you can also find links for additional information and MSDSs from the following internet site: www.ilpi.com/msds/index.html. For pure chemicals, Hazardous Substance Fact Sheets are available from the State of New Jersey Department of Health. These are written for lay audiences and are found at www.state.nj.us/health/eoh/rtkweb/rtkhsfs.htm. The National Institute of Occupational Safety and Health's (NIOSH) Pocket Guide to Chemical Hazards is found at www.cdc.gov/niosh/npg/pgdstart.html. These documents give information about the health and safety hazards of the chemical as well as safe handling and storage information. It is very important to know how the chemicals must be stored since some chemicals are incompatible with others and could cause an explosion if they were to accidentally leak. Chemicals should be stored by chemical class not by chemical name! In addition, fireproof storage cabinets may be needed for some flammable chemicals like certain solvents.

Follow all safety instructions on the label and MSDS. Be sure that you have proper cleanup equipment on hand should there be an accidental spill. Do not wait until you have a spill to find out if you are prepared!

Use Proper Ventilation

The best kind of ventilation to use is local exhaust ventilation such as that found in fume hoods. These should be vented to the outside with their exhaust far away from the air-intake vents for the building's ventilation system. For any vapors that escape into the room itself, there should also be good general ventilation to dilute the vapors so they will not be as dangerous.

It is important for buildings with fume hoods to have adequately designed ventilation systems. Since fume hoods, when operating, pull a high flow of air, sufficient makeup air needs to be provided to the room. Otherwise, the room could become negatively pressurized. This could result in pollutants and odors being pulled into the room from other locations. It could also make it hard to open the room door from the inside, thus creating a safety hazard. Conversely, fume hoods need to have sufficient airflow so that all vapors are exhausted to the outside. Proper ventilation balancing in a building with laboratories and fume hoods is critical, but often overlooked.

Wear Proper Personal Protective Equipment

Personal protective equipment (PPE) should also be worn when working around chemical and biological hazards. PPE should be worn when it is anticipated that the employee/student may have contact with blood, other potentially infectious materials, mucous membranes, and non-intact skin; and when handling or touching contaminated items or surfaces. The MSDSs will give recommendations on proper protective equipment (like goggles, chemical-protective gloves, aprons) to be worn when working with those chemicals. Remember that not all personal protective equipment is equal; there is no such thing as a glove that is impervious to all chemicals. Chemical resistant gloves are usually made out of different kinds of rubber (natural, butyl, neoprene, nitrile, and Viton) or different kinds of plastic (polyvinyl chloride (PVC), polyvinyl alcohol, and polyethylene). Use MSDSs as well as the glove manufacturers' chart to know what kind of gloves to use for what chemical. A recommendation on what type of gloves should be used for a particular chemical can be found at the NIOSH's Recommendation for Chemical Protective Clothing at www.cdc.gov/niosh/ncpc1.html. Though this may be a good place to start, you should still consult with the manufacturer's chemical protection guide before making your decision. An example of such a guide on-line may be found at www.ansell-edmont.com/us/html/frameset.htm. There are also film types of gloves such as 4H [www.safety4.com/guide/set_guide.htm] or Silver Shield [www.northsafety.com/chemglv.htm].

For workers, the OSHA regulations for hand protection should be followed. These can be found at www.osha-slc.gov/OshStd_data/1910_0138.html.

In addition to gloves, the following PPE should be worn when working around chemicals or biohazards:

• Eye protection: Face shields and goggles should be worn whenever procedures with a high potential for creating aerosols are conducted. For workers, OSHA regulations for eye and face protection can be found at www.osha-slc.gov/OshStd_data/1910_0133.html.

• Chemical apron or lab coat to protect street clothing from chemical or biological hazards

• Foot protection: Sandals and other types of open-toed shoes should not be worn in labs.

It is important that all PPE be kept clean and properly maintained. Cleaning is particularly important for eye and face protection where dirty or fogged lenses could keep one from seeing well. PPE should be inspected, cleaned, and maintained at regular intervals so that it can give the level of protection it was designed to give. For general information about general OSHA regulations regarding PPE, go to www.osha-slc.gov/OshStd_data/1910_0132.html.

Work Practices to Maintain Good Quality Air

• Make sure that chemical and biological storage areas are separate from classroom or office areas.

• Chemical storage areas should have a dedicated exhaust to the outside so that chemical vapors and odors do not get into the main ventilation system.

• Diluted substances, rather than concentrates, should be used whenever possible.

• Use techniques that require the least amount of hazardous materials.

• Properly use fume hoods to capture particles, gases, and vapors to prevent them from being released into the general lab area where they can be breathed in.

• Immediately report any spills and take appropriate action according to your lab's spill response plan.

• Alert the lab supervisor to any rules and/or regulations that are being broken.

Reference

1. Crump C, Bearer CF, Paschal DC, Rodenbaugh D, Etzel RA. Mercury exposure in high school chemistry teachers. Archives of Environmental Contamination and Toxicology. 1996;31:206-209.