Questions regarding the safety of drinking water remain more than 24 hours after a tanker overturned on an Interstate 91 southbound exit ramp in Enfield and caused 2,600 gallons of gasoline to spill.

At least three homes on Kalish Avenue, located directly behind the crash site, remain unable to use their water, according to North Thompsonville Fire District Chief Earl Provencher. They and others in the neighborhood rely on private wells to pump water, and using those wells could cause potentially contaminated groundwater to seep towards the homes and expand the overall area of contamination, according to Jeff Chandler, a supervisor with the Department of Energy and Environmental Protection (DEEP) Emergency Response Unit.

Though Connecticut Water confirmed to NBC Connecticut that the gasoline spill has not affected Enfield’s public water, DEEP is working with the Department of Public Health (DPH) and the North Central District Health Department to locate private wells which could be affected. Crews installed new wells between nearby private wells and the crash site which are equipped with devices to monitor for potentially contaminated groundwater.

Chandler said groundwater generally travels at a relatively slow pace of “feet per day,” but he said the soil consistency at the scene of the accident is sandy and porous, which could allow contaminated groundwater to move more freely.

Exit 49 on I-91 southbound remained closed as crews excavated truckloads of contaminated soil from the crash site. Chandler said the soil is delivered to a local facility where it is incinerated. The process is meant to burn off remaining hydrocarbons and allow for the soil to be re-used elsewhere.

Crews will need to backfill wherever soil has been excavated once that process is complete, and the CT DOT will have to inspect their work before the road can be reopened.

Since 2003, there have been 57 crashes between the exit 49 ramps and where they intersect with Route 5, according to the UCONN Crash Data Repository. Seventeen of those crashes were in the last three years.