The city is refusing to make public a contract for study of the controversial technology known as cured-in-place plastic. The study is part of the process for deciding whether to use CIPP to repair major water mains in Cambridge.

“The scope of work should be made as public as the work generated” by the study, said Ali Hendren, a Fresh Pond resident and administrator at the Harvard School of Public Health. “I would want to make sure the scope is wide enough and robust enough.”

The Law Department has denied a request under the state public records law for a copy of the contract with consultant CDM Smith. Maureen Vilanova, public records access officer, wrote Sept. 19 that the contract was exempt from disclosure because it “relates to policy development and an ongoing deliberative process.” Cambridge Day has appealed the decision.

The public development exemption “is limited to recommendations on legal and policy matters found within an ongoing deliberative process,” according to a guide on the public records law published by Secretary of State William Galvin’s office. The guide lists several types of documents that might fall under the exemption – none of them contracts.

Earlier, city government spokesman Lee Gianetti had said the ”scope of work” under the contract had been “finalized” based on “input from the Water Board and the general public” at the June meeting of the board. Gianetti did not provide details.

Less disruptive, but concerning

CIPP involves inserting a flexible plastic tube into a pipe while it’s underground, then hardening the lining with heat. Developed in the 1970s, it is attractive because workers don’t have to dig up the street to repair pipes. It has been used for years to repair sewer and drain pipes, and, more recently, drinking water pipes.

The city is considering using CIPP in a large transmission pipe that connects a storage tank in Belmont’s Payson Park with the Cambridge Water Treatment Plant at Fresh Pond; the pipe may need to be replaced in five years.

Some scientists and others have questioned the health impacts of using CIPP in water systems, saying they are concerned about chemicals leaching from the plastic lining into drinking water. In May 2017 the Water Board held a public presentation at which two academics outlined safety concerns. Five city councillors introduced an order a year later – this May – calling for the city to collect “all relevant scientific information” before deciding whether to use the process.

That move was placed on file, rather than adopted, after City Manager Louis A. DePasquale reiterated assurances that it would be done. The study by CDM Smith is part of that process.

Arouses skepticism

Now, the city’s refusal to make the contract for the study public is arousing anxiety among those who were already worried about whether the city will turn to the process.

“If they’re not being public about something that’s going to affect the whole city – we can’t even see this [contract] – this should make us nervous that the city is making decisions without public knowledge,” said Alice Heller, a board member of the Fresh Pond Residents Alliance. “Hearing this makes me skeptical that the city has our best interests” in mind.

At its May meeting, according to minutes, the Water Board presented a detailed list of specifications outlining what it wanted the consultant to look at. Some of those reflected questions presented at the May 2017 event about whether there is adequate knowledge about leaching and health effects of CIPP, particularly long-term. It isn’t clear how many, if any, of those items were included in the contract.

At that meeting, CDM Smith engineers also presented an outline of what the company planned to examine, some similar to items listed by the board. Both the board and the consultant focused on possible environmental and health impacts from the lining process; the board specified it wanted to see any information on effects as far out as 50 years and impacts on air as well as water. A board member also asked the consultant to identify gaps in research findings.

Health Department promise

Also at the meeting, city environmental health director Sam Lipson of the city’s Public Health Department said he would look at the relative risks of using CIPP, along with possible ways of mitigating health impacts, once the consultant had completed research into materials and methods to be used.

Among other things, Lipson proposed testing for “major breakdown products of CIPP materials exposure to treated water in the one location where this material has been used in the past,” according to minutes of the meeting.

He was referring to a 900-foot section of water main along Main Street between Wadsworth and Ames streets, where the city made repairs with the lining process in 2014. City officials disclosed this for the first time in this past May; they said it was necessary because the area’s proximity to the MBTA line made conventional repair very difficult and time-consuming.

When asked in August about testing, city spokesman Gianetti said the city has not tested the water in the section of pipe repaired with CIPP because it wasn’t analogous to using the process in the Belmont supply pipe. Gianetti gave no indication that any tests were planned.

“Ideally” public

According to minutes of the May water board meeting, CDM Smith planned to present a “draft technical review” of the lining process at the September or October meeting; “ideally” the meeting would be public. There was no presentation at the Sept. 11 meeting, according to board president Ann Roosevelt.

When Lipson and the consultant have completed their work, “we would hold another public meeting in November or December to share information gathered and to consider additional steps that may need to be taken,” the May minutes said.

The timetable could be pushed back if the engineering examination of the condition of the Belmont transmission main concludes that it doesn’t need repair in the near future. A report presented at the September meeting found the pipe was in good condition, but leak tests haven’t been completed, Roosevelt said.

Use elsewhere

A spokeswoman for the Massachusetts Water Resources Authority said it has not used CIPP.

Boston has used it, or plastic pipe, to repair or replace a tiny fraction of its 1,000-mile system: 4,889 feet out of a total of 5.3 billion feet, spokeswoman Dolores Randolph said in an email. She did not give a specific figure for the lining process, but said it was used at Cleveland Circle and the Custom House area, where water pipes ran under tracks and other “massive utilities” that made conventional repairs impossible.

Randolph reiterated what Cambridge officials have said: that the lining process and its materials are approved by the state Department of Environmental Protection and the private National Standards Foundation, an industry group that sets standards and certifies materials.

Critics, though, have questioned whether those certifications require enough testing.