CIPP Industry Defends Styrene Use

Organizations in the cured-in-place-pipe (CIPP) industry are seriously concerned about a recommendation before the U.S. Department of Health and Human Services (HHS) to designate styrene as a “reasonably anticipated carcinogen,” implying that it could be a cause of cancer in humans.

Styrene is a primary ingredient used to manufacture the thermoset resins used in cured-in-place-pipe sewer rehabilitation.

“Designating styrene a reasonably anticipated carcinogen would have severe impact on the CIPP industry,” said Gerry Muenchmeyer, P.E., technical director of NASSCO (National Association of Sewer Service Companies). “It would affect thousands of employees of companies in that industry and the nation’s much-needed sewer rehabilitation program.”

Cured-in-place pipe technology was introduced 40 years ago and has developed into a billion dollar industry that provides municipalities and private companies an environmentally sound means to rehabilitate failing underground pipeline infrastructure, often at a fraction of the cost of traditional replacement techniques.

Muenchmeyer said there appears to be no evidence that styrene, as it is currently used in the CIPP process, poses any health hazards to the workers installing the CIPP or to the general public.

NASSCO and other organizations representing companies that use styrene in various products have requested that action on the recommendation be delayed until further, comprehensive scientific studies can be conducted.

NASSCO and its members have launched a grassroots campaign to educate legislators and the public on this issue. Letters have been written to HSS Secretary Kathleen Sebelius and several members of Congress. The response from HHS — basically that ramifications of the designation are beyond the scope of the recommendation — is not encouraging.

The recommendation is awaiting the signature of Secretary Sebelius. There has been no indication when the secretary will make a decision whether to sign the recommendation or delay action for further scientific study and review.

“Prematurely labeling a chemical that is critical to many products and processes across North America would have detrimental effects on the environment, the economy and ultimately, the general population,” Muenchmeyer said.

Last January, NASSCO Executive Director Ted DeBoda sent the first of two letters to Secretary Sebelius saying that NASSCO joins the American Composites Manufacturing Association and Styrene Information and Research Center requesting that before making a final decision, the department should make a reasonable “double check” of the science of the study recommending that styrene be designated a reasonably anticipated carcinogen.

DeBoda explained the use of unsaturated polyester styrene based resin in the CIPP process and noted the U.S. Environmental Protection Agency considers CIPP a major tool in the repair and reconstruction of the nation’s failing pipeline infrastructure.

“Our research,” DeBoda wrote, “has shown that the levels of styrene exposure to workers and the public during field installation of CIPP are significantly lower than standards set by NIOSH [National Institute for Occupational Safety and Health] and the EPA in a typical manufacturing or plant facility. Also, once the installed product is cured, it becomes essentially inert with no long-term associated styrene issues.

“To our knowledge, there have not been any verified cases of health related issues associated with the use of styrene,” he pointed out.

The letter to Secretary Sebelius was answered by Linda Birnbaum, director of the National Institute of Environmental Health Sciences and National Toxicology Program, who said that she would make sure the Secretary was aware of the points raised by NASSCO. She included a copy of an informational document describing the process used to reach the decision to recommend classifying styrene as a reasonably anticipated human carcinogen (see sidebar).

In late February, DeBoda sent a second letter to Birnbaum, again stating NASSCO’s position on the issue, posing questions NASSCO believes should be addressed before making a decision about whether styrene is a reasonably anticipated human carcinogen, and again cited studies that have found no concern for styrene causing cancer.

Wrote DeBoda: “NTP’s classification of styrene as ‘reasonably anticipated to be a human carcinogen’ or the mere perception of the term ‘a carcinogenic hazard,’ may result in thousands of job losses with little or no documented public health risk. Since many independent studies in North America and Europe have concluded that the styrene exposure health hazard does not exist, we recommend that further research and education be performed first to find out the true effects of styrene on humans.”

Birnbaum’s March 17th reply contains the heart of the issue:

“The issues you raise address parts of the risk assessment process beyond hazard identification and are outside the scope of the RoC [report on carcinogens] . . . The RoC is an informational scientific and public health document that identifies and discusses agents, substances, mixtures, or exposure circumstances that may pose a hazard to human health by virtue of their carcinogenicity . . .(sic). The RoC does not present quantitative assessments of the risks of cancer associated with these substances. Thus listing of substances in the RoC only indicates a potential hazard and does not establish the exposure conditions that would pose cancer risks to individuals in their daily lives. Such formal risk assessments are the responsibility of appropriate federal, state, and local health regulatory and research agencies.”

Obvious questions are: How scientific was the methodology used by the National Toxicology Program to base its recommendation to designate styrene as an anticipated carcinogen? How responsible is it to disregard short- and long-term repercussions of the designation?

NASSCO believes that labeling styrene a reasonably anticipated carcinogen will affect the entire sewer rehabilitation industry. Within this industry, CIPP accounts for about one billion dollars of sewer rehabilitation annually in North America, said Muenchmeyer.

Without styrene or with restrictions on styrene, far fewer miles of sewers would be fixed resulting in more sewer overflows and detrimental effects on the environment.

Municipalities and sewer districts working under EPA consent decrees, Muenchmeyer believes, would find it difficult and more costly to meet the requirements of those consent decrees, if they could at all.

“If styrene is labeled a reasonably anticipated carcinogen,” concludes Muenchmeyer, “it will not, of course, simply disappear. However, it will become highly regulated, including warning labels. Many governmental bodies will choose not to use styrene in sewer rehabilitation products or will possibly use other, less effective, products than CIPP for sewer rehabilitation. All of this adds up to a less effective way to repair the nation’s sewer infrastructure, with the resulting negative impact on the environment.”

NASSCO Position Statement

The use of styrenated resins in cured-in-place pipe (CIPP) is a major factor in the rehabilitation of sewer and water pipelines nationwide. For 40 years, this technology has been providing a significantly lower cost, no-dig, permanent rehabilitation alternative to open-cut pipe replacement.

When compared to traditional construction methods, the use of CIPP is a significantly faster and more environmentally friendly, green technology. Installation requires significantly less diesel and gasoline exhaust emitting equipment on the job site, and less pollution from vehicles emitting exhaust while waiting in traffic through construction detours. Fewer disturbances mean lower economic impacts when fewer if any businesses are shut down or residential areas are disturbed for extended periods of time. Since there is little or no excavation, there are fewer, if any, solids discharged into rivers and streams and less pollutants into the air.

The CIPP industry and its many related materials and equipment suppliers employ tens of thousands of people and save cities and towns significant money on pipeline rehabilitation. This considerably lower-cost technology has equipped cities and towns with the financial ability to reconstruct their pipeline infrastructure at a fairly aggressive rate, keeping up with their continuing deterioration while creating large employment opportunities throughout the country.

The proposed listing of styrene as “reasonably anticipated to be a human carcinogen” can be so declared with little or no evidence as to any real effect on humans. However, such a declaration will have grave impacts on rehabilitation of the failing pipeline infrastructure throughout the country. Alternative resins could cost three times the amount of styrenated resins, which will result in a substantial increase to the cost of replacing the failing infrastructure.

There exist many exhaustive, but inconclusive studies concerning the possible carcinogenic properties of styrene, mostly associated on its effects on laboratory animals. NASSCO urges additional study and research on this topic, rather than risk serious financial, employment and environmental ramifications on inconclusive data.

NASSCO is a national organization comprised of several hundred members representing the pipeline rehabilitation industry manufacturers and suppliers, municipalities and utility districts, engineers and contracting firms.

Styrene and CIPP

Styrene is a colorless, oily, volatile and flammable water-insoluble liquid made from ethylene and benzene. It is an unsaturated compound which readily undergoes polymerization and is used in making polystyrene, polyesters, synthetic rubber and other products.

Styrene is naturally occurring in the environment, dissipates quickly in the atmosphere and is highly biodegradable in the presence of water. In fact, styrene can be found in common foods such as strawberries and cinnamon. One reason that styrene may be such a target is its pungent odor (if it smells bad, it must be bad), and its low detection level. Most people can smell styrene in the air at the low concentration of less than one part per million.

It is estimated that about 10 percent of the styrene used in North America is for manufacturing composites, which includes cured-in-place-pipe (CIPP). The other 90 percent is used in the manufacturing of many other products such as polystyrene plastic (Styrofoam) and thermoplastics.

Styrene is a principal ingredient of the thermoset resins used in cured-in-place-pipe which is composed of a composite material. Without styrene, this type of cost-effective sewer rehabilitation would not be possible, leaving CIPP contractors, and ultimately sewer system operators, looking for other CIPP resins to use for pipeline rehabilitation. Although styrene substitutes exist, none can match styrene in performance, cost and availability of supply.

CIPP consumes about 5 percent of the styrene used for composite manufacturing, or about 0.5 percent of the total styrene used in North America. Although CIPP consumes millions of pounds of styrene per year, it is a relatively small consumer compared to the entire styrene industry. This means that if all styrene consumers begin searching for styrene substitutes, the CIPP industry may have difficulty finding a reliable supply because larger consumers would have priority purchasing power. (This brief summary of styrene’s uses is based on information provided by NASSCO.)


Andrew Fitzsimons, project manager for the Washington Suburban Sanitary Commission (WSSC), offers this comment about styrene and cured-in-place-pipe (CIPP) rehabilitation.

“CIPP lining provides system owners with a valuable, low-cost alternative to traditional open-cut construction. Listing styrene as a ‘reasonably anticipated carcinogen’ will likely result in a drastic increase in the cost of CIPP rehabilitation. As CIPP costs approach that of open-cut, system owners like WSSC will increasingly choose open-cut pipe over CIPP. Losing this lower-cost alternative will increase the capital costs associated with failing pipeline infrastructure replacement, particularly those mandated by EPA consent decrees. These costs will be passed on to the rate payers.”

Informational Process Report from DHHS

Editor’s Note: The following “informational document” was provided by Linda Birnbaum, director of the National Institute of Environmental Health Sciences and National Toxicology Program on behalf of HHS Secretary Kathleen Sebelius. The document the process used to reach the decision to recommend classifying styrene as a reasonably anticipated human carcinogen.

Evaluation of Styrene for the Report on Carcinogens (RoC) by the National Toxicology Program (NTP)
The RoC is a scientific and public health document that provides information about the relationship between the environment and cancer. It is a congressionally mandated report that identifies agents, substances, mixtures, or exposures (collectively called “substances”) that may pose a carcinogenic hazard for human health for people in the United States. Responsibility for preparation of the RoC has been delegated to the NTP.

The NTP has followed an established, multi-step process with multiple opportunities for public input to review styrene for the 12th RoC ( This process includes both public and inherently governmental steps. The NTP has set up a website for the 12th RoC that provides access to public information for the review of styrene (choose “S” at In addition, the NTP has used existing listing criteria to evaluate the scientific evidence on styrene and reach a proposed listing recommendation for styrene as reasonably anticipated to be a human carcinogen. These criteria used by the NTP to fulfill the statutory obligation to publish the RoC have been in place for more than 13 years (61 Fed. Reg. 50499, September 26, 1996). They were the product of a thorough and public review and, since their publication, have remained unchanged despite being revisited periodically.

To carry out the review of styrene, the NTP compiled a background document on styrene. In accordance with NTP guidelines, the human cancer, experimental animal, and mechanistic scientific information included in the background document and considered in the evaluation of styrene came from publicly available, peer-reviewed sources. The NTP also convened three, independent, scientific groups (external expert panel and two internal, Government review groups) to assess the body of scientific evidence on styrene, apply the listing criteria, and advise the NTP on whether styrene should be listed in the 12th RoC and, if so, in what classification, either known or reasonably anticipated to be a human carcinogen. The expert panel was convened at a public meeting with opportunity for comment to peer review the draft background document on styrene and provide a listing recommendation. Meetings of the two governmental, scientific review groups followed the public comment period on the expert panel’s recommendation and were closed to the public.

Following the review of styrene by the three groups, the NTP considered the independent recommendations of each group, the public comments, information available in the background document, and any new, relevant scientific information on styrene, and formulated its proposed listing recommendation for styrene as reasonably anticipated to be a human carcinogen. The draft substance profile for styrene with the NTP’s proposed listing recommendation was released for public comment (73 Fed. Reg. 78364, December 22, 2008) and then peer-reviewed by the NTP Board of Scientific Counselors (BSC) and additional ad hoc reviewers at a public meeting with opportunity for public comment. The BSC and ad hoc reviewers provided input to the NTP on whether the scientific information cited in the draft substance profile supported the NTP’s preliminary policy decision to list styrene as reasonably anticipated to be a human carcinogen. Consistent with NTP policy, the scientific evidence cited in support of the NTP’s recommendation came from publicly available, peer-reviewed sources.

The NTP has completed the review process for candidate substances under consideration for listing in the 12th RoC. The NTP considered the input from the BSC peer review, public comments, and any new, relevant scientific information on styrene in finalizing its recommendation on the listing status of styrene, and prepared the draft RoC. The NTP Director shared the draft RoC with the NTP Executive .Committee. The draft RoC is submitted to the Secretary, Health and Human Services, for review and approval. Once approved, the Secretary will transmit the 12th RoC to Congress and it will be released to the public.

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