New research calls for the implementation of new safeguards for cured in place pipe repair (CIPP), and a study of the potential health and environmental concerns for workers and members of the public who come into contact with emissions from the pipe repair method.
CIPP was first invented in the 1970s, and is widely used to repair sewer, stormwater and drinking water pipes. The method involves inserting a resin impregnated fabric tube into a damaged pipe and curing it in place with hot water or pressurised steam, occasionally with ultraviolet light. Put simply, CIPP results in the manufacture of a new plastic pipe inside the old, damaged one.
In a statement, Andrew Whelton from Purdue University's Lyles School of Civil Engineering and the Environmental and Ecological Engineering program, says the process can emit chemicals into the air, sometimes in visible plumes, potentially exposing workers and the public to a mixture of compounds that can pose health hazards.
Whelton led a team of researchers to conduct a test at seven steam-cured CIPP installations in Indiana and California. The researchers captured the emitted materials, including styrene, acetone, phenol, phthalates and other volatile and semi volatile organic compounds (VOCs and SVOCs), and measured their concentration. The results have been detailed in a paper published in Environmental Science & Technology Letters.
The study revealed that the chemical plume, often thought of as harmless steam, was in fact a mixture of organic vapour, water vapour, particulates of condensable vapour and partially cured resin, and liquid droplets of water and organic chemicals.
“CIPP is the most popular water-pipe rehabilitation technology in the United States,” Whelton said. “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.”
"CIPP workers, the public, water utilities, and engineers think steam is emitted," he said. "What we found was not steam. Even when the chemical plume was not visible, our instruments detected that we were being chemically exposed."
Calls for action
The researchers are now calling for a response. They have briefed the National Institute for Occupational Health and Safety about the findings, which has occupational safety and health experts who can investigate workplace hazards.
Analysis of the samples, captured in the chemical plume materials from two sanitary sewer pipe installations and five stormwater pipe installations, found hazardous air pollutants, suspected endocrine disrupting chemicals, and known and suspected carcinogens.
Pulmonary toxicologist Jonathan Shannahan exposed mouse lung cells to the captured materials. Plume samples from two of four test sites displayed toxicity effects while two did not.
"This suggests that there are operational conditions that may decrease the potential for hazardous health effects," Shannahan stated. "Since exposures can be highly variable in chemical composition, concentration, and exposure duration our findings demonstrate the need for further investigation."
Investigation by the researchers found that CIPP workers rarely used respiratory protection.
"The CIPP process is actually a brilliant technology,” said Jonathan Howarter, an assistant professor in materials science and environmental and ecological engineering who co-authored the study. "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 multiphase mixture is safe. We also are not aware of any study that has examined the persistence of this multiphase mixture in the environment."
A number of changes have been called for by the researchers, including workers being instructed to always wear chemically resistant gloves when handling resin tubes. They also say that health officials should always be notified when people complain of odours near CIPP sites.
“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,” Whelton said. “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.”