Travolta, Phoenix immersed in fiery research

John Travolta and Joaquin Phoenix are immersed in research for their latest movie Ladder 49 - so much so that producers are worrying they will come to harm in their enthusiasm for fire-fighting, according to imdb.com.

The pair, along with co-star Balthazar Getty, spent a month with real fire-fighters in Baltimore, Maryland to get hands-on training for their roles but their enjoyment sparked grave concerns in the people paying their salaries.