Environmental, Health and Safety Services

Exposure Control

Routes of Exposure

It is important to understand how infectious microorganisms get into the body in order to choose the proper engineering controls, administrative controls, or PPE when there is the potential for exposure to disease. The routes of disease transmission, with definitions, are listed below.

  • Injection : Introduction of material directly into the bloodstream. Injection exposure may be from needle stick, or cut/puncture from any sharp object
  • Inhalation : Introduction of material into the respiratory tract via aerosolization or spray of the material near the breathing zone.
  • Ingestion : Introduction of material into the gastrointestinal tract via aerosolization or spray of material near the face, or any activity that brings dirty or gloved hands near the face. Such activity can include eating, smoking, applying makeup or lip balm, scratching the face, chewing on pens or pencils.
  • Absorption : Introduction of material through intact skin or through mucous membranes. This route of exposure is more common with a chemical exposure since infectious microorganisms are typically too large to pass through intact skin. These organisms CAN pass through the mucous membranes lining the nose, mouth, eye lids.

Methods of Exposure Control

Certain procedures and tools must be used to keep employees safe from exposure to infectious diseases found in biological material (such as human/animal tissues or fluids) or laboratory stocks of infectious microorganisms. These procedures and tools include universal precautions, engineering controls, work practice controls, use of personal protective equipment, housekeeping, laundering, and use of signs and labels as described in the following sections.

Universal Precautions/Standard Precautions

“Universal precautions," as defined by the Centers for Disease Control (CDC), are a set of precautions designed to prevent transmission of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and other bloodborne pathogens when providing first aid or health care. Under universal precautions, blood and certain body fluids of all patients are considered potentially infectious for HIV, HBV and other bloodborne pathogens. Universal precautions should also be followed when working with any biological material that has the potential to infect an employee with a disease whether it is a cultured microorganism, or blood/tissues/other body fluids from human or animal sources.

The terms ‘universal precautions’ and ‘standard precautions’ are interchangeable. Universal Precautions include:

  • Assume that ALL human blood is positive for HIV, HBV, and HCV or other human pathogen
  • Assume that ALL other human fluids/tissues are also positive for infectious disease
  • Use Personal Protective Equipment to avoid skin contact with potentially infectious materials
  • Use Personal Protective Equipment to avoid eye, nose, & mouth contact with potentially infectious materials
  • Avoid punctures/sticks with contaminated sharp objects.

Engineering Controls

Engineering controls are devices and tools that prevent exposure to health hazards. These sorts of safety controls must be used, in conjunction with Work Practice Controls, to eliminate or minimize employee exposure.

These devices/equipment must be inspected and maintained on a regular basis by the Departmental Coordinator, supervisor, or his or her designee. Worn parts and equipment shall be replaced as soon as indicated through the inspection process.

Some common engineering controls used to protect employees from infectious agents include:

Handwashing Facilities: Each department shall provide readily accessible handwashing facilities. This means that there must be a facility to supply adequate running water, soap, and single-use towels or hot-air drying machines.

Alternate Handwashing Devices : When running water handwashing facilities are not feasible, the department shall provide either an appropriate antiseptic hand cleanser with clean cloth/paper towels OR antiseptic towelettes.

Needle Safety Devices : Departments using medical sharps must make all reasonable attempts to implement the use of these safety devices instead of traditional sharps. There are many products on the market that are designed to prevent needle-stick-injuries. Some examples include:

  • Needleless connectors for IV delivery systems (e.g., blunt cannula for use with pre-pierced ports and valved connectors that accept tapered or luer ends of IV tubing)
  • Protected needle IV connectors (e.g., the IV connector needle is permanently recessed in a rigid plastic housing that fits over IV ports)
  • Needles that retract into a syringe or vacuum tube holder
  • Hinged or sliding shields attached to phlebotomy needles, winged-steel needles, and blood gas needles
  • Protective encasements to receive an IV stylet as it is withdrawn from the catheter
  • Sliding needle shields attached to disposable syringes and vacuum tube holders
  • Self-blunting phlebotomy and winged-steel needles (a blunt cannula seated inside the phlebotomy needle is advanced beyond the needle tip before the needle is withdrawn from the vein)
  • Retractable finger/heel-stick lancets

Desirable features in Needle Safety Devices:

  • The device is needleless
  • The safety feature is an integral part of the device
  • The device preferably works passively (requires no activation by user)
  • The user can easily tell whether the safety feature is activated
  • The safety feature cannot be deactivated and remains protective through disposal.
  • The device is easy to use and practical.


Sharps Containers: Proper containers for storage of contaminated sharps shall be provided by the departments. They shall meet the following description:

  • Puncture resistant,
  • Closeable,
  • Leakproof, and
  • Labeled (Biohazard) or color-coded (orange/red).

Splash Guards: Labortory equipment that can potentially vaporize or splash infectious material should be equipped with a splashguard (Picture 2) or similar protective device.


Biosafety Cabinets: Are in use in biological laboratories across campus whenever the possibility of exposure to air-borne pathogens is present.

Work Practice Controls

Work practice controls are procedures that employees need to follow in order to keep themselves safe. These required procedures are to be followed by all “at risk” employees and shall be enforced by all departments.

Hand/Skin Washing: It is extremely important that all at-risk employees follow strict hand/skin washing procedures at the following times:

  • After removing gloves or other Personal Protective Equipment
  • Following contact with potentially infectious material

If an exposure occurs, hands and other skin areas must be washed with soap and water OR alcohol based antiseptic cleanser (in the absence of water). Mucous membranes shall be flushed with copious amounts of water for at least 15 minutes. DO NOT use soap or alcohol based antiseptic cleansers for infectious agent exposures to eyes or nose/mouth.

When an antiseptic cleanser or towlette is used, washing with water and soap should follow as soon as possible.

Sharps Handling: Whenever a needle or other sharp device is exposed, injuries can occur. In addition to risks related to device characteristics, needlestick injuries have been related to certain work practices such as:

  • Recapping,
  • Transferring a potentially infectious fluid between containers, and
  • Failing to properly dispose of used needles in puncture-resistant sharps containers.

If recapping cannot be avoided, it must be accomplished through the use of a mechanical device, such as forceps. Also, the one-hand scoop method is allowed, if done safely.

Minimize Splashing: All procedures involving potentially infectious materials shall be performed in such a manner as to minimize splashing, spraying, spattering, and generation of droplets.

Avoid Ingestion : Eating, drinking, smoking, applying cosmetics or lip balm, and handling contact lenses are strictly prohibited in work areas where there is a reasonable likelihood of occupational exposure to infectious material.

  • Food and drink shall not be kept where potentially infectious materials are present.
  • Mouth pipetting/suctioning of potentially infectious materials is prohibited.

 Dealing with Contaminated Equipment: The following procedures shall be followed when having potentially contaminated equipment serviced:

  • Look for evidence of contamination.
  • Decontaminate if necessary and feasible.
  • If NOT feasible, label equipment with BIOHAZARD label.
  • Include on the label which parts are contaminated.
  • Convey information to affected employees and servicing representative prior to shipping, so that precautions can be taken.

Personal Protective Equipment

Where occupational exposure remains after the implementation of Engineering and Work Practice Controls, Personal Protective Equipment shall also be used. Departments shall provide, at no cost to the employee, appropriate PPE including, but not limited to:

  • Gloves
  • Gowns
  • Lab coats
  • Face shields
  • Masks
  • Respirators
  • Eye protection
  • Mouthpieces
  • Resuscitation bags
  • Pocket masks
  • Mechanical respiratory devices

PPE is considered appropriate if it is needed for, and is capable of preventing, blood or other fluids from passing through to the employee's clothing, skin or mucous membranes. PPE selection shall be made after completing a PPE Hazard Assessment as outlined in Virginia Tech’s Personal Protective Equipment Program.

Departments shall ensure proper use, accessibility, cleaning, disposal, repair and replacement of PPE.

Employees must remove PPE before leaving the work area or whenever the PPE has become saturated with blood or other potentially infectious materials. Disposable PPE must NOT be reused. Used PPE must be placed in an appropriately designated area or container for storage, washing, decontamination, or disposal.

Employees are not permitted to take their protective equipment home and launder it. It is the responsibility of the department to provide, launder, repair, replace, and dispose of personal protective equipment as needed.

Gloves: Gloves shall be worn when it can be reasonably anticipated that the employee may have hand contact with potentially infectious biological material, when performing vascular access procedures on humans, or when handling contaminated equipment or surfaces.

Guidelines for Glove Use

Glove Type:



When To Discard:




Torn, punctured, contaminated, when removed for any reason




Cracked, peeling, torn, punctured, deteriorating

Face and Eye Protection: Masks, respirators, goggles, glasses, and/or face shields are to be worn whenever splashes, spray, spatter, or droplets of potentially infectious materials may be generated, when eye, nose or mouth contamination can be reasonably anticipated, or when the pathogenic organism’s mode of transmission is via aerosol. Masks and other respiratory protection devices may only be purchased after consultation with EHSS personnel.

Body Protection: Gowns, aprons, lab coats, clinic jackets, and other protective body clothing are to be worn in occupational exposure situations when appropriate. The type and characteristics of the PPE will depend upon the task and degree of exposure anticipated.


All worksites are to be maintained in clean and sanitary conditions at all times. Each work area must establish a written cleaning schedule. All such schedules should be included in this manual, following this section.

Decontamination/Cleaning of surfaces and equipment shall be performed at the following times:

  • At the frequency determined in the written schedule
  • Following a contamination incident
  • Following routine procedures that may cause contamination
  • At the end of work shifts, if contamination may have occurred since last cleaning

The following are surfaces that are likely to need decontamination:

  • Lab equipment
  • Bench/Counter tops
  • Re-useable receptacles that may store biological material
  • Environmental surfaces such as patient examination tables
  • Large areas such as an ambulance interior, animal holding room, entire lab room, etc.

Protective coverings should be removed and replaced as soon as feasible when they become obviously contaminated or at the end of the workshift if they may have become contaminated during that shift. Coverings include:

  • Plastic wrap
  • Aluminum Foil
  • Imperviously-backed absorbent paper

Broken glass shall not be picked up directly with the hands. It shall be cleaned up mechanically. Use a brush and dust pan, tongs, or forceps.

Employees must never reach into containers of contaminated sharps.

Chemical Decontamination

Acceptable methods of chemical decontamination


Acceptable for…


Special Precautions


Sodium Hypochlorite

General use; not recommended for skin disinfection. Will corrode metals.

Common household bleach diluted to a 1/10 to 1/100 with water

1. Strong oxidizer

2. Corrosive

Note: May discolor certain materials.

At high concentrations and extended contact time, considered cold sterilants


General use

70-90% ethyl or isopropyl alcohol for 10-30 minutes contact time

1. They evaporate fast and have limited exposure time

2. Can cause contact dermatitis

1. Less active against non-lipid viruses

2. Ineffective against bacterial spores

3. Concentrations above 90% are less effective


Most often used as antiseptics and in surgical soaps

0.47% concentration for 10-30 minutes

Can cause skin irritations



Used for the same applications as glutaraldehyde; can be sporacidal

4-8% concentration for 10-30 minutes

Formaldehyde is a human carcinogen and creates respiratory problems



Glassware and instruments; items that can be submerged and soaked in a covered container; considered a sporacidal

2% concentration for 10-600 minutes; rinse with sterile water to remove residuals

Sensitivity problems developed in workers using it at high levels


Phenolic Compounds

General use on walls, floors, bench tops; bacteria; fungi; and lipid-containing viruses

0.2-3% concentration for 10-30 minutes

Can cause depigmentation; occupational leukoderma; idiopathic neonatal hyperbilirubinema

Not active against spores or non-lipid viruses

Quaternary Ammonium Compounds (Quats)

General use; active against gram-positive bacteria and lipid-containing viruses

0.1-2% concentration for 10-30 minutes

Can cause minor skin dermatitis

1. Least effective against gram-negative bacteria and not active against non-lipid-containing viruses

2. Easily inactivated by organic materials, are corrosive, and not sporicidal

Laundry—Proper Practices

Contaminated laundry—laundry that has been soiled with blood or other potentially infectious materials—must be handled, stored and transported in accordance with very specific requirements as follows:

  • Contaminated laundry must be handled as little as possible.
  • Employees that have contact with contaminated laundry must wear protective gloves and other appropriate personal protective equipment.
  • Contaminated laundry must be bagged or containerized at the location where it was used and may not be sorted or rinsed in the location of use.
  • Contaminated laundry containers must be labeled with the Biohazard symbol, or color-coded fluorescent orange or orange-red.
  • If laundry is wet and presents reasonable likelihood of leakage to the exterior of the container, the container must be capable of preventing soak-through.
  • Contaminated laundry must be handled following Universal Precautions. Contaminated laundry should not be taken home to be laundered by staff. EHSS strongly recommends that Departments arrange to have contaminated items laundered on site (in an area separate from where the contaminated laundry is generated) or via an appropriate vendor.

Labels and Signs


The OSHA Bloodborne Pathogens Standard requires labels to be placed on items that may be contaminated by bloodborne pathogens. This may include:

  • Equipment (e.g., refrigerators, freezers, and incubators);
  • Shipping containers;
  • Primary and secondary agent containers;
  • Regulated medical waste containers; and
  • Sharps containers.


All access doors to labs or animal rooms where biologicals are present must be posted with biohazard information in addition to the emergency contact information required by Virginia Tech's Chemical Management Program:. For additional information on required signage, go to biological_safety.php. This biohazard information must include:

  • The universal biohazard symbol which is red/orange in color with black lettering (see right);
  • Name of the agent(s) present in the lab;
  • Required biosafety level for working with these agents;
  • Required immunizations for entering room;
  • Personal protective equipment that must be worn in room;
  • Special procedures for exiting the lab; and
  • Name and telephone number of the Principal Investigator, other responsible person(s), and EHSS emergency personnel.