Specially-trained firefighters were called to a "large fuel spill" on a busy road near Llanidloes.
Fire and rescue crews from Newtown and Llanidloes attended the incident on the A470 roundabout at around 9am on Thursday morning.
An Environmental Protection Unit was also sent to try and contain the spilt diesel fuel.
A Mid and West Wales Fire and Rescue Service spokesman said: "On Thursday, crews from Llanidloes and Newtown attended a diesel spillage on the A470 roundabout near Llanidloes.
"An Environmental Protection Unit was mobilised to the incident and firefighters used two hose reel jets, a fogging unit and granules to clear the diesel spillage.
"The Highways Agency was also in attendance. The Fire Service left the incident at 10.47am."
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here