One challenge is that the resin safety data sheets do not disclose all of the chemicals, and some entirely new ones are created during heating.

Chemical plumes rising from nearby manholes and contractor exhaust pipes are also not just “steam.” These plumes contain highly concentrated chemical mixtures, uncooked resin, particulates and nanoplastics that can harm human health. When we examined the heating process in the lab, we found that as much as 9% of the resin was emitted into the air.

CIPP production is known to discharge about 40 chemicals. Some cause nausea, headaches and eye and nasal irritation. They can also lead to vomiting, breathing difficulties and other effects.

Styrene, the most frequently documented chemical, is acutely toxic, and “reasonably anticipated” to cause cancer, according to the National Research Council. Chemicals other than styrene can be responsible for plume toxicity.

So far, chemical exposures have been reported in at least 32 states and seven countries. In addition to schools, this process has contaminated homes, restaurants, medical facilities and other businesses. Companies have been cited for exposing their workers to unsafe levels of styrene.

The earliest U.S. incident we know about was in 1993 at an animal shelter in Austin, Texas. Seven people were overcome by fumes and transported to a hospital. In 2001, fumes entered a hospital inn Tampa, Florida, causing employee breathing problems. Since then, hundreds more people are known to have been exposed, and the numbers are likely much higher.

In our experience, exposures are rarely made public. Municipalities have encouraged people affected by the fumes to only contact the CIPP contractor and pipe owner. In some cases, people were told the exposures were always harmless.

Chemicals can enter buildings through sinks, toilets, foundation cracks, doors, windows and HVAC systems. The chemicals can even enter buildings that have water-filled plumbing traps. Anticipating this risk, bystanders have been told to cover their toilets and close all windows and doors.

Wind can help dilute outdoor chemical levels. However, concentrated plumes can rush through buried pipes into nearby buildings. Bathroom vent fans may sometimes increase the indoor chemical levels. Levels that should prompt firefighters to wear respirators have been found in the buried pipes.

The highest levels have been found during and after the heating process.

...continued