TURNERS FALLS — The future of a planned housing development on First Street is uncertain after environmental tests showed six contaminants in the parcel’s soil.

A Phase II Environmental Site Assessment was conducted at the town-owned, 0.65-acre lot by the U.S. Department of Transportation’s Volpe Center to “evaluate the presence or absence of petroleum products or hazardous substances ... stemming from potentially buried construction and demolition waste and historic fill material,” according to the project’s executive summary. Pioneer Valley Habitat for Humanity has been planning to develop five to six affordable housing units on the site.

Samples gathered in August revealed quantities of arsenic, barium, lead, zinc, benzo(a)pyrene and acenaphthylene that exceeded concentrations allowable by the Massachusetts Contingency Plan, the report summarizes. These findings must be reported to the state Department of Environmental Protection (DEP) within 120 days, according to Montague Town Administrator Walter Ramsey. He noted the quantities of hazardous materials were not that much higher than acceptable levels, but still constituted “reportable condition to the DEP.”

The Volpe Center projects it is “likely that these soil exceedances are attributable to the fill material” used for the implementation of the site’s current parking lot. There was no groundwater contamination observed.

The Volpe Center’s report advises that “site workers performing future site investigation or housing redevelopment work at the subject property should use caution when disturbing or coming into contact with soil.” Ramsey added that the soil would need to be removed, tested and replaced with clean soil prior to development. This, he said, would require additional time and money to execute.

“Hopefully it is not a dealbreaker to the project,” he said.

Pioneer Valley Habitat for Humanity, which is facilitating the housing development, requested — and was granted — a six-month purchase and sale extension for the property by the Montague Selectboard on Monday night that extends the deadline to close from the end of the year to June 30, 2024. Megan McDonough, executive director at Pioneer Valley Habitat for Humanity, cited her organization’s desire to explore its options during this time, given the soil contamination as a variable.

“We need time to figure out the next steps,” she said.

Selectboard Chair Rich Kuklewicz added that ensuring the First Street property has a “clean bill of health” before its sale would be the right thing for the town to do.

“We want to see it through,” McDonough said, “but … we want to be sure that it can be cleaned up before we close on land and move it forward.”

Reach Julian Mendoza at 413-930-4231 or jmendoza@recorder.com.