NORWICH, Conn. (WTNH) — A family evacuated their home after a 25-50-gallon oil spill was found in the basement Friday night, fire officials said.

According to the Norwich Fire Department, residents reported strong smells of gas inside a two-family home on Boswell Ave at 8:52 p.m. Friday.

Upon arrival, officials said they noticed a strong smell of fuel oil but all meter readings were negative.

During the investigation, companies found about 12 inches of water with about one inch of oil covering the entire 20 x 24-foot basement floor.

Fire officials said that they determined that the oil was either coming from an abandoned tank that was partially submerged inside the basement or from an abandoned tank outside the home.

Companies also found two operating sump pumps which were pumping the water and oil outside and onto the ground. These pumps were disconnected and the property was secured, fire officials said.

The Connecticut Department of Energy and Environmental Protection (DEEP) and the Norwich Building Official also investigated the scene.

According to the fire department, 25-50 gallons of #2 home heating oil were found along with another possible 100+ gallons still on site.

CT DEEP said they could not reach the property owner so they contacted an emergency clean-up contractor to immediately remove the oil. They plan to reach out to the property owner again to talk about possible contamination from the outside.

Officials said that the first floor of this two-family home was condemned as a result of the spill.

The residents are staying with family until the clean-up process is finished and the power is restored.

Norwich Public Utilities and the Norwich Building Official plan to re-evaluate the home on Monday, officials said.