What is styrene?
Styrene is a colorless liquid that evaporates easily and smells sweet. It is used to make a polymer called polystyrene. Many commercial products are made of polystyrene, such as Styrofoam, disposable utensils, plastic dishware, and appliance casings.
Styrene can also be found in cigarette smoke, car exhaust, and photocopier or printer toner. There may be small amounts of styrene in food that is stored in polystyrene containers.
What is cured-in-place pipe (CIPP)?
When sewer pipes are damaged they can either be dug up out of the ground and physically replaced, or a procedure called cured-in-place pipe (CIPP) can be used to reline the sewer. In this procedure, a tube embedded with styrene resin is fed through the pipe. Once the old pipe has been lined with this material the polymerization step is started in a procedure called curing. When this is complete the sewer pipe has a new polystyrene lining.
A drawback of CIPP is styrene vapors that are emitted before the tube is cured. These styrene vapors can rise out of sewer pipes and into residences. After the tube is cured the styrene should go away, so any exposure to styrene should be short-term.
How can styrene affect my health?
Breathing high amounts of styrene can irritate the eyes, nose, and lungs. Workers who are exposed to high amounts of styrene for a long time can have injury to their nervous systems. The National Institute for Occupational Safety and Health (NIOSH) recommends workers be exposed to no more than 50 ppm styrene on average over a 10-hour workday. The Occupational Safety and Health Administration (OSHA) has a permissible exposure limit of 100 ppm average over an 8-hour workday for styrene. These values are based upon studies of health effects in workers exposed to styrene, including reports of irritation at concentrations above 200 ppm and reports of weakness, dizziness, and changes in color vision in people exposed at high concentrations over a long period of time.
For short-term exposure (two weeks or less) the Agency for Toxic Substances and Disease Registry has set a minimal risk level (MRL) of 5 parts per million (ppm). This level is thought to be safe for the general population to be exposed to, including infants and children. Styrene has a strong odor and can be smelled at very low levels that are much too low to cause any harm (about 0.5 ppm or less).
How can I prevent styrene from getting into my house after CIPP is installed?
Styrene vapors can get into houses through drains to the sewers. The best way to prevent this is to pour water down drains to make sure the drain traps are full of water. This creates a barrier to vapors rising from the sewer. If there are drains that do not have a trap, such as some basement drains that are straight vertical pipes, these can be temporarily covered with a damp towel to help keep vapors from entering the house. Closing off rooms where vapor is getting in can help keep the smell out of other rooms. Use fans or windows to air out rooms.