Radiation is a natural part of our environment. Our bodies are constantly exposed to different levels of radiation from natural and man-made sources, like the sun or our microwave ovens. Radiation safety levels are set to ensure that we are protected from harmful radiation. So, what are the safe levels of radiation for occupational exposure?
Radiation safety levels
Radiation can be measured in different units such as rad, rem, or sieverts. The dose limits set by international organizations such as OSHA or the NCR are designed to keep exposures below levels that might cause health effects. These standards are based on scientific studies of what levels of exposure can be tolerated by humans without causing harm to health.
Ionizing radiation is a type of radiation that removes electrons from molecules and atoms. Excessive exposure can cause mutations and damage to a person’s DNA. Some sources of ionizing radiation are fuel cycle facilities, nuclear power plants, industrial devices used for scientific research and measurement, and even x-ray machines and CT scanners.
Non-ionizing radiation is a low-energy type of radiation. It is less likely to cause harm than ionizing radiation because it does not have enough energy to ionize cells. Some sources of non-ionizing radiation are heat and light from the sun or lightning.
For workers covered under the ionizing radiation standard, OSHA recommends that exposure should not exceed 1.25 rem per calendar quarter for the whole body. For hands and feet, the limit dose can go up to 18.75 rem for every quarter. As for skin exposure, the number is 7.5 rem per quarter year.
Although the standard does not state a maximum exposure limit, the NRC (Nuclear Regulatory Commission) recommends that whole-body and skin exposure should not exceed the dose of 5 rem per year, averaging over five consecutive years. Also, eye lens exposure should not exceed the dose of 15 rem per year.
Protection against radiation
Employers much ensure that radiation doses are kept ALARA or as low as reasonably achievable. Spending less time near a source, working farther away from a source, and shielding from a source can all help decrease the levels of exposure.
Having a radiation emergency preparedness and response plan is also critical to protecting your workers from excessive radiation. The first step in building the plan is to identify the risks involved.
Radiation incidents can occur from:
- Handling or transporting radioactive materials
- Spills, leaks, or releases of radioactive materials
- Misuse of radiographic materials
Radiation workers who operate in high-radiation areas are generally required to wear dosimeters so their individual doses can be monitored.
Finally, employers must provide the required training for workers to safely operate near sources of radiation.
As we mentioned before, ionizing radiation ionizes the cells inside the human body and can modify DNA. Exposure to over 200 rem can cause hair loss, while 1000 to 5000 rem could impact heart and brain function. Excessive exposure can also lead to headaches, fatigue, tumors, cancer, Alzheimer’s disease, or Parkinson’s disease.
It is important to note that OSHA also has exposure limits set for catastrophic radiation emergencies. In an incident where all controls and appropriate actions are implemented, lifesaving emergency responders can be exposed to over 25 rem.
To learn more about different OSHA standards, make sure to head to our resources page.