A 22-year-old American has lost both her legs in a Bahamas tour boat explosion that killed one American woman and injured several others.

Stefanie Schaffer, of Rutland, Vermont, is in a medically-induced coma after the tour boat burst into flames off the island of Exuma shortly after 9am on Saturday.

She was one of 12 people on board, which included 10 Americans and two Bahamians.

Stefanie was on a summer vacation with her teenage sister Brooke, mother Stacey, and stepfather Paul Bender.

A family member told DailyMail.com that Stefanie and Stacey remain hospitalized in Nassau.

The company that ran the trip, 4C's Adventures, declined to comment on the explosion to DailyMail.com because they are under investigation.

Stefanie Schaffer, 22, (left), her teenage sister Brooke (middle), and their mother Stacey (right) were among the injured when a tour boat exploded in the Bahamas. Stefanie lost both legs

An American woman was also killed and several others were injured when the tour boat exploded

Stefanie is currently too unstable to be flown back to the United States.

'She's in really critical care right now and in really serious shape,' the relative said. 'I know she has really bad internal injuries.'

She said Stacey shattered one of her legs in the explosion and suffered multiple broken bones and internal injuries.

Brooke and Bender managed to both escape with only scratches and bruises.

Among the others injured in the blast was teen Haiden Jones, his brother Kyle Ackerman, his mother Sheila Jones, and her boyfriend John Inman, Haiden's father said on Facebook.

'Prayers needed my son Haiden was on vacation in the Bahamas with friends and family when their charter boat exploded and caught fire! My son Haiden his brother Kyle his Mother Sheila, boyfriend John, girlfriend Brooke and Paul are all ok just cuts and bruises.

'Many prayers needed for Stacey Bender (Schaffer) Stephanie Schaffer last update Stacey and her daughter Stephanie still in the ICU,' CJ Jones said.

A family member told DailyMail.com that Stefanie and Stacey (pictured together) remain hospitalized in Nassau. Stefanie is currently too unstable to be flown back to the US

The family member said Stefanie also suffered 'really bad internal injuries' and is 'in really serious shape'

The relative said Stefanie is a 'very outgoing' dancer who recently graduated college.

'The scary thing is Stefanie doesn't know that she's lost her legs, and that's what really upsets me,' she said.

'She's going to wake up from this coma and realize "I don't have any legs". It's breaking my heart.'

A GoFundMe campaign has since been launched by the family to raise money for Stefanie and Stacey's medical expenses.

Stacey (pictured with Stefanie) shattered one of her legs in the explosion and suffered multiple broken bones and internal injuries

Stefanie was described by the relative as a 'very outgoing' dancer who recently graduated from college

Stefanie is pictured here in a past photo with Brooke, who is currently flying back to the US

The relative said she is hoping Stefanie will soon be stable enough to be flown back to Florida for further medical treatment.

Stefanie's father and brother are both en route to the Bahamas to be with her.

'Hang in there Stef I'm on my way,' George John Schaffer, Stefanie's brother, wrote on his Facebook Sunday night.

Four of the injured Americans on the boat were immediately airlifted to a hospital in St Petersburg, Florida with the help of the US Coastguard after the explosion.

Video captured the horrific moment the small boat went up in flames on Saturday morning

A crowd of people could be seen watching the horrible site before some jumped in to help

A group of people were later seen carrying on of the victims to the shore after the explosion

It is not clear if the American woman was killed in the blast or if she died later from her injuries. Her name has not been released.

The explosion sent flames and plumes of black smoke soaring into the air, as seen in a photograph taken by Instagram user Chris Topperwien.

Several people on a nearby boat jumped into the water to help and dragged at least one person to safety.

Exumas and Ragged Island MP Chester Cooper confirmed that a woman had died and that two people, both Americans, were in an 'extremely critical condition' in the Nassau hospital.

A tour boat carrying 10 Americans and two Bahamians exploded off the island of Exuma on Saturday. Four of the injured Americans were airlifted to Florida by the US Coastguard

It now appears that those two Americans are Stefanie and her mother.

'This is a sad day for Exuma and a sad day for our American friends,' Cooper said in a statement.

'We are saddened and our hearts our hurting, but we will get through this together. Your prayers, as always, are needed and appreciated.'

The cause of the explosion is under investigation by the Exuma branch of the Royal Bahamas Police Force.