Have you used the cured-in-place pipe repair method? It’s effective and non-disruptive, but be aware of potential health risks

by Brianna Crandall — August 29, 2017 — The increasingly popular cured-in-place piping (CIPP) pipe repair method is based on an innovative technology that seems to produce noteworthy results in getting the job done on a variety of pipes effectively and quickly, with little disruption. But new research from Purdue University is calling for immediate safeguards and further research into the widely used method to understand the potential health and environmental concerns for workers and the public.

Cured-in-place pipe repair (CIPP)

The procedure, called cured-in-place pipe repair, or CIPP, was invented in England in the 1970s, and became available more recently in the United States. It involves inserting a resin-impregnated fabric tube into a damaged pipe and curing it in place with hot water or pressurized steam, sometimes with ultraviolet light. The result is a new plastic pipe manufactured inside the damaged one.

The method has come in high demand for government work, since CIPP is a flexible way to repair many pipes, sewers, and culverts without disrupting the road and incurring more costs. It has also proven popular for water pipes in such facilities as hotels, hospitals, schools, public buildings, and high-rises because of its crucial ability to keep traffic flowing for the business or institution.

Research discovered hazards

However, the CIPP process can emit chemicals into the air, sometimes in visible plumes, and can expose workers and the public to a mixture of compounds that can pose potential health hazards, according to Andrew Whelton, an assistant professor in Purdue University’s Lyles School of Civil Engineering and the Environmental and Ecological Engineering program.

Researchers near CIPP installation with vapors

Purdue researchers perform testing during a CIPP installation. (Purdue University photo)

Whelton led a team of researchers who conducted a testing study at seven steam-cured CIPP installations in Indiana and California. The researchers captured the emitted materials and measured their concentration, including styrene, acetone, phenol, phthalates and other volatile (VOC) and semi-volatile organic compounds (SVOC). Results from their study are detailed in a paper appearing in Environmental Science & Technology Letters.

The findings show that the chemical plume, commonly thought of as harmless steam, was actually a complex mixture of organic vapor, water vapor, particulates of condensable vapor and partially cured resin, and liquid droplets of water and organic chemicals.

Whelton asserted:

Short- and long-term health impacts caused by chemical mixture exposures should be immediately investigated. Workers are a vulnerable population, and understanding exposures and health impacts to the general public is also needed.

Research results

The researchers briefed the U.S. Centers for Disease Control and Prevention’s (CDC) National Institute for Occupational Health and Safety (NIOSH) about their findings. NIOSH has OSH experts who can investigate workplace hazards.

Chemicals found during the study include hazardous air pollutants, suspected endocrine-disrupting chemicals, and known and suspected carcinogens. Emissions were sometimes highly concentrated and affected by wind direction, speed and the worker’s activities, Whelton noted.

A waxy substance was found in the air, and materials engineers determined it was partially cured plastic, styrene monomer, acetone, and unidentified chemicals. No respiratory protection was used by CIPP workers, and a review of online videos, images and construction contracts indicates respiratory safety equipment use was not typical, he said.

To evaluate chemical plume toxicity, pulmonary toxicologist and assistant professor Jonathan Shannahan and a graduate student exposed captured materials to mouse lung cells. Plume samples from two of four sites tested displayed toxicity effects, and two did not. Shannahan stated:

This suggests that there are operational conditions that may decrease the potential for hazardous health effects. Since exposures can be highly variable in chemical composition, concentration, and exposure duration our findings demonstrate the need for further investigation.

At the same time, existing testing methods are not capable of documenting this multi-phase chemical exposure, Whelton pointed out.

Findings contradict conventional thinking

In 2017, Whelton completed a one-and-a-half-day CIPP construction inspector course for consulting and municipal engineers and contractors as part of a different research project. From this experience, Whelton remarked:

CIPP workers, the public, water utilities, and engineers think steam is emitted. What we found was not steam. Even when the chemical plume was not visible, our instruments detected that we were being chemically exposed.

The team’s Freedom of Information Act requests to cities and utilities revealed 49 public reports of chemical air contamination associated with CIPP activities, along with complaints filed by homeowners and businesses who, anecdotally, described strong and lingering chemical odors and illness symptoms.

Video of workers at CIPP installation

Workers repair a damaged pipe using the CIPP process, which emits a white plume containing a complex mixture vapors and chemical droplets. The workers wore no respiratory protection. (Purdue video)

John A. Howarter, an assistant professor of materials engineering and environmental and ecological engineering at Purdue, urged additional research because the procedure has not been well studied for health and environmental risks. He said:

The CIPP process is actually a brilliant technology. Health and safety concerns, though, need to be addressed. We are not aware of any study that has determined what exposure limit to the chemical mixture is safe. We are not aware of any study that indicates that skin exposure or inhaling the multi-phase mixture is safe. We also are not aware of any study that has examined the persistence of this multi-phase mixture in the environment.

Whelton said, “In the documents we reviewed, contractors, utilities, and engineering companies have told people who complain about illness symptoms that their exposures are not a health risk. It’s unclear what data are used for these declarations.”

Utilities and municipalities sometimes cite worker chemical exposure standards established by the NIOSH as acceptable for the general public. Whelton said this comparison is “wrong and invalid,” particularly in the case of children, and pointed out that “CIPP workers can be exposed to more than one chemical at a time, in addition to droplets, vapor and particulates.”

The team found that the uncured chemicals also might pose hazards: The nitrile gloves Whelton wore on one occasion deteriorated from contact with the uncured resin tube. From the researchers’ observations and online images and videos, they determined that workers sometimes did not wear gloves while handling the chemicals. Whelton advised:

Workers should always wear appropriately thick chemically resistant gloves while handling uncured resin tubes. No one should handle these materials with their bare hands.

Whelton added that state and local health officials must be alerted when people complain about odors near CIPP sites and illness so they can investigate — the health officials that researchers spoke with were “unaware of illness and odor complaints from CIPP activities,” since the public often speaks instead with CIPP contractors and engineers. Whelton concluded:

Engineers should act immediately because it is their professional responsibility to hold paramount the safety, health, and welfare of the public according to their code of ethics. We have seen evidence that companies and utilities do not understand what materials are created and emitted by CIPP processes or the consequences of exposure. Our new study indicates workers, the public, and the environment needs to be better protected from harm.

The researchers are working to develop safeguards, including a new type of handheld analytical device that would quickly indicate whether the air at a worksite is safe. The research was primarily funded by a RAPID response grant from the National Science Foundation, with additional support from public donations and Purdue University.

Results from the Purdue air testing study are detailed in a paper appearing on July 26 in Environmental Science & Technology Letters. The study files can freely be downloaded and are open-access. A YouTube video is also available that summarizes the research findings.

The study follows a discovery three years ago when researchers reported that chemicals released by CIPP activities into waterways have been linked to fish kills, contaminated drinking water supplies, and negative impacts to wastewater treatment plants. The previous research paper, available in the same publication, demonstrated that chemicals released into water by CIPP sites can be toxic — the CIPP waste dissolved freshwater test organisms within 24 hours at room temperature.