On Tuesday morning at 7 a.m., trucks began hauling away crushed concrete from the AvalonBay construction site on Witherspoon Street, where rental units are being built at the former site of the University Medical Center at Princeton. The town’s engineering director Bob Kiser reported at a meeting of Princeton Council Monday night that he had met with the developer that morning and plans for site remediation were put into place.

Originally, 30 trucks were to be used each day to remove the materials. A revised plan calls for 10 С at least for now. “They will see how it goes and then perhaps increase the number of trucks depending on how it proceeds,” Mr. Kiser said, adding that the process would be monitored by the engineering department and the local police. It could take two to three months to complete the cleanup, he said, and in some instances the hauling of materials to a location near Bethlehem, Pennsylvania, may extend past 2 p.m. and include some Saturdays.

Construction work was stopped at the site after crushed concrete from the old hospital building tested positive for PCBs. Further testing was done by the New Jersey Department of Environmental protection, and materials came up negative for PCBs. But PAHs (polycyclic aromatic hydrocarbons) were detected to exceed residential standards. AvalonBay is required to cap the site in order to remediate it, using clean soil, crushed stone, concrete slabs, and other materials.

Asked if the plan took into consideration the children walking near the site on their way to and from Community Park School, Mr. Kiser said he had met with the school principal and the school is comfortable with the plan. “We’ll make sure all operations are done in a swift manner,” he said.

Some residents who live near the site continue to express concerns about environmental safety (see Mailbox, page 11). Paul Driscoll, who lives on Harris Road, is among those questioning why groundwater is not being tested.

“They did find in their test results that came back from the DEP that mercury was detected above the impact of groundwater standards,” he said. “But apparently there won’t be any testing of the groundwater because there wasn’t any to test during the drought. But now that we have had rain, would it be possible to test it?”

Mr. Driscoll added that EcolSciences, the company retained by AvalonBay to do environmental testing, found PAHs in 2011. “I think a lot of us feel, why not take that extra step and check the groundwater to see if anything can be done? All along, AvalonBay at different points has refused to do testing. Why aren’t we testing the groundwater for mercury? Mercury is very serious. The other concern is the demolition itself, which could have contributed to further contamination. How has this impacted the surrounding neighborhood?”

Mr. Kiser said that testing of groundwater was attempted during the period of drought this summer, and there was no groundwater to test. “It was felt that this type of contamination isn’t the type that would migrate down into the groundwater, unless it was a very high level, and groundwater was not previously found,” he said when asked why further testing of the water has not been done. “It was checked before, when they removed the underground storage tanks. They couldn’t find any groundwater when they dug down, or evidence of high groundwater, in the area. So they have determined that it’s not a risk. We have discussed it with our consultant, Ira Whitman, and he does not have any objection.”