Cured-in-place pipe (CIPP) repair has been a staple of infrastructure maintenance for decades. The process involves feeding a limp “pipeliner” fiber tube into a broken pipe and curing it in place with hot water, steam, or ultraviolet light, providing a new barrier to keep water or wastewater from leaking. But new research raises questions about the safety of the practice for those workers asked to perform it and those living in the area.
The CIPP process often produces plumes of vapor, which can look like steam, rising into the air. While these clouds are typically thought to be harmless, Dr. Andrew Whelton, an assistant engineering professor and researcher with Purdue University, believes they indicate a serious health risk to those who may breathe them in.
“Over the years, I have been contacted by people asking about chemical exposures they reported to have experienced when nearby sewer pipes were being repaired with CIPP,” Whelton said. “The people who have contacted me reported odors and [associated] illness symptoms... In these cases, utilities and contractors declared the exposures were safe but often did not do any testing to confirm this.”
Whelton said that a couple contacted him after they thought CIPP-produced chemicals entered their infant’s bedroom. The couple had done some research of their own and found that barely any tests had been conducted to determine what chemicals were released during CIPP installation. That’s when Whelton decided to take matters into his own hands.
“I began looking into what was known about chemicals used during CIPP manufacture and created during the pipe repair process, how emitted chemicals were prevented from leaving the uncured resin tube, and examined available air monitoring data to determine whether or not independent testing data existed that backed up the claims told to those people who were being exposed,” he said. “I grew very concerned that not only may the chemicals emitted from CIPP into the air be more numerous than what had been reported, but their magnitude might pose a health risk to workers and the nearby public.”
Along with other Purdue researchers, Whelton found that there were very few air monitoring studies for CIPP and those that did exist “lacked scientific rigor.” The team compiled an air contamination incident list and reviewed worker safety literature and information about CIPP materials. It found enough evidence of danger to produce a list of 49 different chemical air contamination incidents in the U.S. associated with CIPP installations.
Obtaining a grant from the National Science Foundation based on its research, the team initiated an air monitoring study of its own at seven CIPP sites. Capturing the plumes of vapor emitted at these sites, the research found styrene, acetone, phenol, phthalates, and other volatile and semi-volatile organic compounds
“The complexity and magnitude of different materials emitted from CIPP pipes was surprising,” Whelton said. “When we characterized the materials we collected from the air, we became very concerned about the safety of workers and the public.”
However, the research did not clearly determine any human health impacts the emitted materials could have and many proponents of CIPP replacement would still argue that the practice is safe.
“I have 35 years of working with this product,” said Rick Fast, the owner of CIPP Services, when asked why operations should not be concerned about these potential risks. “I have monitored my wet-out facility as well as the emissions from the curing process. I have spent $250,000 on monitoring all of these things over the years.”
For Whelton’s part, the presence of materials within CIPP plumes has at least warranted further research, if not immediate health concerns.
“The toxicity tests conducted do not indicate human health impacts can or will occur, but indicate the material requires additional scrutiny because health impacts cannot be ruled out,” he said. “We believe additional work needs to be conducted to further understand the exposures as well as short- and long-term health impacts of these multi-phase mixture exposures.”
The Purdue researchers have contacted the National Institute for Occupational Safety and Health (NIOSH) to make it aware of the issues identified and the two groups are working together to determine workplace risks and advise workers about CIPP safety practices.
“Installers, managers, and unions can submit a formal request to NIOSH to get assistance,” said Whelton. “At the request of employees, managers, and union representatives … NIOSH can conduct free workplace health hazard evaluations of CIPP worksites.”
In the meantime, Fast recommended the use of respirators, fresh air blowers, and gas detectors to ensure that CIPP crews are safe during installation.
Image credit: "20110719-RD-LSC-0130," U.S. Department of Agriculture, 2011, used under an Attribution 2.0 Generic license: https://creativecommons.org/licenses/by/2.0/