PORTLAND, Ore. (AP) – Zenith Energy threatened Thursday to sue the city of Portland unless it reverses a recent decision to block the firm from adding underground pipes at its oil terminal along the Willamette River.

The Oregonian/OregonLive reports Zenith gave the city a week to change its stance or face legal action.

Portland’s city attorney and mayor’s offices declined comment, citing the possible legal action. Mayor Ted Wheeler said previously he supported disallowing the pipes at the Zenith property, where the firm has stored and transferred tar sands crude oil.

A lawyer for the company, Eric L. Martin, sent a letter Thursday to Portland interim Community Technology Director Elizabeth Perez, saying the city’s Oct. 18 refusal to allow it to add the three pipes violates the business’ agreement with the city.

Zenith says the city’s refusal to allow it to add pipes to transport biofuel directly counters a city policy promoting green energy in Portland. The company said it plans to run only biofuels and other non-fossil-fuel liquids through the pipes although Zenith has acknowledged that the new pipes would be physically capable of transporting fossil fuels.

Information from: The Oregonian/OregonLive, http://www.oregonlive.com