When a compact fluorescent lamp (CFL) or a longer fluorescent light fixture breaks, it releases a small amount of elemental mercury (\(\text{Hg}^0\)) into the surrounding air. These bulbs contain mercury, typically 4 milligrams or less in a CFL, which is necessary for their operation. The immediate concern is not the liquid metal itself, but the mercury vapor that is released when the glass shatters and the internal components are exposed to room temperature. This vapor is odorless and invisible, making proper response procedures important for minimizing potential exposure.
The Specific Health Risk of Mercury Vapor
The danger posed by a broken bulb comes primarily from inhaling the elemental mercury vapor, which is readily absorbed by the body. Approximately 80% of inhaled mercury vapor passes through the lungs and quickly enters the bloodstream. This form of mercury is highly lipid-soluble, a property that allows it to easily cross biological barriers.
Elemental mercury is able to pass through the blood-brain barrier before it is oxidized within the body. Once across this barrier, the mercury can accumulate in the central nervous system (CNS), where it can interfere with neurological function. The two primary target organs for absorbed elemental mercury are the brain and the kidneys.
Exposure from a single broken light bulb is generally considered an acute, low-level event. However, if cleanup is not performed correctly, the mercury may vaporize slowly over time, leading to chronic, low-level exposure. This long-term exposure can lead to a gradual build-up in the body, targeting the CNS and potentially resulting in persistent neurological effects.
Immediate Steps Following Bulb Breakage
The first action following a bulb breakage is to ensure the safety of all occupants and pets. Everyone must immediately vacate the room where the incident occurred to minimize the time spent inhaling the newly released mercury vapor. This limits the initial exposure to the highest concentration of the substance.
After evacuating the area, the next step is to ventilate the space by opening any windows and exterior doors. Ventilation should be maintained for a minimum of 10 to 15 minutes to allow the vaporized mercury to dissipate outside. Crucially, the central heating, ventilation, and air conditioning (HVAC) system must be turned off to prevent the circulation of contaminated air throughout the rest of the building.
If the room has a door, it should be closed to seal off the immediate area during ventilation. A fan should only be used if it can be placed to blow air out of the room and directly to the outside. This prevents drawing mercury vapor into other parts of the home.
Symptoms of Mercury Vapor Exposure
Acute inhalation of mercury vapor can sometimes lead to symptoms that affect the respiratory system. These may include the onset of a cough or shortness of breath.
Other signs of acute exposure can involve the digestive and nervous systems. Some individuals may experience nausea, a metallic taste in the mouth, or a sudden headache. In cases of higher or prolonged exposure, more distinct neurological effects, such as muscle tremors, nervousness, or increased salivation, may be observed.
Symptoms following a low-level exposure from a broken bulb are often very mild or delayed. If any of these signs develop following the breakage, consult a medical professional. Even if symptoms are absent, the proper cleanup protocol must be strictly followed to eliminate the source of the vapor.
Safe Cleanup and Disposal Procedures
Ensure the room has been thoroughly ventilated and remains clear of people and pets before starting cleanup. Wear disposable, non-porous gloves, such as nitrile or latex, to prevent direct skin contact with the glass fragments and phosphor powder. A vacuum cleaner must never be used, as the suction and heat will aerosolize the mercury, spreading the toxic vapor and contaminating the vacuum itself.
Use two pieces of stiff paper or thin cardboard to carefully scoop and push the large pieces of glass and debris together. Avoid using a broom, as its bristles can break the material into smaller particles and spread contamination. After removing the larger fragments, use sticky tape, such as duct tape or packaging tape, to pick up all tiny glass shards and the fine, white phosphor powder coating.
All collected debris, including the contaminated tape, gloves, and scooping material, must be immediately placed into a sealable container. A glass jar with a tight-fitting lid or a heavy-duty, sealable plastic bag is suitable. Once sealed, the container should be placed outside the home to wait for proper disposal.
Mercury-containing waste is classified as hazardous and cannot be disposed of in regular household trash. Contact the local waste management authority or environmental agency for guidance on hazardous waste collection sites or drop-off locations. After the container is removed, the room should be aired out for several additional hours, and any clothing or shoes that contacted the area should be wiped clean or discarded if heavily soiled.