Washington, Oct 25 (IANS): The death toll from a massive car wreck has increased to eight with 63 others injured due to a "superfog" of smoke from marsh fires in the US state of Louisiana and dense morning fog, authorities said.

The authorities revealed the death toll on Tuesday night, reports Xinhua news agency.

The National Weather Service said there were multiple wetland fires in the region on Monday and smoke from the fires mixed with fog to create a "superfog," resulting in extremely poor visibility.

As many as 168 vehicles were involved in the series of crashes leading to a mile-long fiery pileup, the Louisiana State Police said on tuesday evening.

Witnesses on Monday morning initially reported two deaths from a box truck that slid underneath an 18-wheeler, according to local media.

One tanker truck carrying a hazardous liquid was also reportedly off-loaded due to a compromised tank.

The pileup caused a cluster of fires leaving a dozen vehicles burnt.

The superfog which led to extremely poor visibility was formed by smoke from local wetlands fires combined with dense fog.

It is expected to be around for days.