Education, training, and procedures

Safe use of hazardous materials in the workplace depends on the cooperation of individuals who have been educated in the science and technology of the materials, who have technical training specific to their application, and who follow administrative and technical procedures established to ensure a safe and orderly workplace.

Security

No matter what source of radiation you work with, one way to enhance safety is to allow access only to those with business in the area. If you see unfamiliar individuals in the area, it is important to question them or call security. Regulatory agencies consider a high degree of security to be an important compliance matter.

Time

The less time we spend around a potentially hazardous material, the less the risk. If you are not needed in a work area, or if your task can be done elsewhere, leave.

Distance

Increasing our distance reduces the risk from any potentially hazardous material. For gamma radiation sources, the dose rate goes down rapidly with distance. Mathematically, I2 / I1 = r12 / r22. This is called the inverse square law. For example, if the dose rate is 100 mrem/hour at 5 cm from a point source, you can calculate the dose rate at 20 cm from the source:

I20cm / I5cm = (5cm)2 / (20cm)2

I20cm = (100 mrem/hr) x (5cm)2 / (20cm)2

I20cm = 6.2 mrem/hr

When working with high energy beta and gamma emitters, remote handling tools can dramatically reduce your hand dose.

Shielding

If the source is a high energy beta or gamma or x‐ray emitter, shielding will reduce the dose rate. For beta emitters, use a low atomic number material such as plastic. For gamma and x‐ray emitters, high atomic number materials such as steel or lead are preferred. However, remember that steel and lead pose their own drop and earthquake hazards. Lead is also a toxic material; use gloves when handling it and wash when you finish. Contact the hazardous waste staff to dispose of lead shielding that is no longer needed.

Clean, orderly laboratories

Most laboratories do not use amounts of radiochemicals that pose an external dose risk. However, area contamination can happen even when materials are carefully handled. Have in the work area only those things needed for the task at hand. Wear gloves and lab coat, and wash your hands after working. Use absorbent countertop paper to hold spills.

General guidance

Some detailed guidance on laboratory safety measures is provided in Table 1.3. Unless, due to special circumstances, your group has received an exception, you must follow the guidance in that table.

Plan ahead

Think about what you are going to do. What can go wrong? What can distract you? Have you reviewed the laboratory protocol? Are all the supplies that you need at hand? Have you checked laboratory and protective equipment to ensure they are working correctly? Have you practiced the entire procedure wearing your protective clothing and using the tools you need? Are you wearing gloves, coat, and impervious shoes? Do you know where the safety shower and eyewash are? Do you know what you are doing, and why?

Before you begin
  • Only individuals who have completed Stanford radiation safety training may use radioactive materials.
  • Review the chemical, radiation, and handling hazards precautions and safety guidance before you prepare for the experiment.
  • Order only approved radiochemicals and quantities. Log receipts. Completely update the storage log at least annually.
  • Store materials to cause minimal dose in work areas. Shield photon‐ and high‐ energy beta‐emitters so that the dose rate at 30 cm is less than 2 mR/hr for low occupancy areas, or 0.2 mR/hr for high occupancy areas. Provide secondary containment.
  • Do not store food or beverages in work areas, or use refrigerators, hot plates, or ovens that are used for radioactive materials work.
  • Eat and drink only at desk or lounge areas. No food or beverages are allowed in VAPAHCS laboratories.
Preparing for the experiment
  • Set up in a well‐ventilated work area. Use a fume hood for volatiles such as I‐125 and S‐35.
  • Keep the work area clean, neat, and uncluttered.
  • Provide secondary containment for spills.
  • Use plastic‐backed absorbent pads or trays to cover work areas.
  • Do not pipette by mouth. Use manipulators.
  • Wear your dosimeter (e.g., film badge) and ring if assigned.
  • Keep a survey meter nearby when using millicurie quantities other than tritium. Use a pancake GM for beta‐emitters and a NaI(Tl) for photon‐emitters.
During the experiment
  • Wear impervious shoes, gloves, lab coat, and safety glasses.
  • Open and dispense reagents behind a splash shield.
  • Use capped tubes in centrifuges and agitators.
  • Use activated charcoal to absorb organic vapors in incubators.
After the experiment
  • Label individual containers before placing them in storage.
  • Change bench covers to avoid cross‐contamination.
  • Survey glassware, apparatus, and central facility appliances. Decontaminate before releasing for house use.
  • Segregate waste. Solidify iodine liquids. Treat pathogens. Log disposals.
Spills or accidents
  • Immediately report injuries or personnel contamination to your supervisor and Health Physics.
  • Promptly report >QLM spills to Health Physics.

TABLE 1.3 STANDARD WORK RULES FOR RADIOCHEMICAL LABORATORIES.