by Safety Management Group
Most people who grew up during the Cold War developed a strong fear of radiation. From fallout shelters to air raid drills, they faced constant reminders of nuclear war and its dangers (although some of what they learned was pretty silly -- such as protecting one’s self from an atomic firestorm by hiding under wooden classroom desks).
While people feared the powerful blasts associated with nuclear weapons, the prospect of radiation was even more terrifying. Invisible and insidious, radiation could have devastating effects on humans. Those who were spared painful deaths would face highly increased chances of cancers and other problems.
So when a tsunami crippled Japan’s Fukushima nuclear power plant this spring, leading to the largest accidental release of radiation since the 1986 Chernobyl disaster, it came as no surprise that many people began to panic. For example, some Pacific coast residents began buying iodine pills to protect themselves from the effects of any radiation that would blow across the ocean.
What they didn’t realize is that, on an average day, most of us are exposed to far more radiation than they could ever expect to receive from an accident halfway across the world. In addition, many of us are exposed to additional radiation through the nature of our jobs.
What exactly is radiation?
Simply put, radiation is energy that travels through the air. While there are many types of radiation, they all fall into one of two classes: ionizing or non-ionizing. The primary difference between the two is that ionizing radiation is able to change the atoms to which it is exposed by removing electrons. That’s an important distinction, because human cells are made up of atoms, so they can be affected by ionizing radiation.
Although non-ionizing radiation can cause atoms to move or vibrate, it cannot remove electrons. Non-ionizing radiation is all around us -- in forms as diverse as radio waves and visible light -- and we use many of those forms in our daily life. When you put a sandwich in a microwave oven, non-ionizing radiation causes the atoms in the sandwich to vibrate and warm up. While the temperature and texture of the sandwich changes, its atoms remain the same, so it’s safe to eat. Similarly, when you place a call with a cell phone, non-ionizing radio waves travel from the phone to the nearest tower to connect you with other towers and, eventually, the person you’re calling.
When people talk about the hazards of radiation, they’re generally referring to ionizing radiation. It’s called that because when it removes electrons from atoms, it creates charged particles that are known as ions. If ions are used in a controlled manner, they can serve very useful purposes, whether that’s generating electricity or wiping out cancer cells in the body. But when the body is exposed in other ways, those useful ions can become quite damaging.
There are three basic types of ionizing radiation: alpha particles, beta particles, and a group that includes gamma rays and x-rays. Each operates at different frequencies and has different effects. For example, when used with special film, x-rays can be sent through an object such as person’s arm or a welded pipe. Areas in the object that are denser will absorb the x-rays, so fewer of them will reach the film, which creates a lighter image. The resulting dark areas can pinpoint problems such as fractures, whether that’s in a pipe or a human bone.
How does radiation affect people?
While all forms of ionizing radiation can have significant health effects, the potential impact depends upon the type of radiation and the amount to which a person is exposed. The different types of radiation affect different kinds of tissue in the body, primarily because of the amount of energy involved and the nature of each type of radiation. As an example, if a person is exposed to equal amounts of alpha and gamma radiation, the alpha particles will concentrate their energy in a much smaller area, and the gamma rays will spread out.
Ionizing radiation can affect any type of living tissue in humans. The severity of the damage from radiation depends upon both the amount of radiation being received and the amount of time involved.
What are known as stochastic health effects are those that result from long-term exposure to low levels of ionizing radiation. The most common of these is the various forms of cancer. A healthy body is able to regulate the growth of new cells and repair those that have been damaged. But when radiation causes damage that affects those regulation and repair processes, cells can grow at an uncontrolled rate. That uncontrolled growth is what we call cancer.
Another type of stochastic effect involves changes to DNA, which is the set of instructions that tells our cells how to form and behave. Changing DNA creates what are known as mutations. Some mutations affect only the individual who has been exposed to radiation, while others can be passed on through the womb to children.
Non-stochastic health effects are usually the result of exposure to significantly higher levels of radiation, often for a very short time. The effects include burns and what’s known as radiation “poisoning,” which can be fatal. High doses of radiation can destroy bone marrow, shut down the nervous and/or digestive system, and lead to the loss of limbs.
Radiation in the workplace
You’re already aware that ionizing radiation in the form of x-ray machines is used in healthcare facilities and manufacturing settings. In healthcare, radiation is also used in a wide variety of diagnostic devices, such as CT scanners, and concentrated for the treatment of tumors and cancers.
In industrial settings, radiation can be used in testing devices, for sterilization of products, for determining the level of moisture in soils, in weapons production, and yes, in nuclear power plants. None of those uses is inherently dangerous, as long as all of the required safety devices and processes are in place and used properly. Those who work with radiation need to understand the safety procedures, the consequences of failing to follow them, and actions to take in the event of an incident.
Fortunately, the radiation levels encountered in the workplace tend to be very small. In fact, the levels that are high enough to cause non-stochastic health effects don’t occur in workplaces. Even workers in towns close to the Fukushima plant received daily doses that were smaller than what most people receive with a dental x-ray. That’s why radiation safety focuses on protecting workers from long-term exposure to lower doses.
Being safe around radiation
As with so many other facets of workplace safety, training plays a critical role in working around radiation. Effective safety training focuses on the three ways workers can limit their exposure to radiation: maintaining a safe distance from the source, limiting the time around the source, and using shielding to limit the exposure. Workers should also know what to do when something goes wrong.
Depending upon the work conditions and the type of radioactive material, other safety measures may also be needed. One example is the use of dosimeters that measure radiation on a cumulative basis and sound an alarm when specific thresholds are reached. If workers are around radioactive dust, respirators may be used to keep the dust from being inhaled. Gloves or other kinds of personal protective equipment may also be needed.
Like fire, radiation can be both a valuable tool and a serious danger. As with fire, there’s no need to be afraid of radiation, but it’s good to develop a healthy respect for its power and to follow practices that minimize the potential danger.