A reveller is helped after an accident with a float from Unidos da Tijuca samba school, February 28. REUTERS/Ricardo Moraes

RIO DE JANEIRO (Reuters) - The top of a towering float collapsed during the final night of the parade by Rio’s elite samba troupes early on Tuesday, injuring 12 people in the second accident to mar Brazil’s glittering Carnival show.

Firemen rushed to rescue costumed dancers caught in the tangled top section of the Unidos da Tijuca samba school, which lost precious time and points in the 75-minute competition down the half-mile parade ground known as the Sambadrome.

Health officials said five of the 12 people hurt were taken to hospital and only one had serious injuries.

They said three people were still in hospital, including a woman with broken legs who was in serious condition and on a respirator. She was injured the previous night when a 3-ton float veered out of control and crushed people against a barrier.

The accidents did not stop the all night parades by the city’s top samba schools that spend millions each year to compete for the most lavish and exotic floats and best dancers driven by powerful drum sections.

Despite a two-year recession and record unemployment in Brazil, the samba schools from poorer neighborhoods of Rio reportedly spent an average $1.5 million on their performances and each took to the Sambadrome with 3,000 to 4,000 dancers, percussionists and star guests wearing extravagant costumes.

The competition’s winner will be announced on Ash Wednesday, the day after the four-day annual pre lenten bacchanalia dubbed the world’s biggest party.

For Unidos da Tijuca, a year of preparations ended in tears just 10 minutes into the parade when the float top caved in, knocking off some of their dancers.

The accident held up the samba school for more than half an hour and its performance overran the 75-minutes allowed per parade, virtually knocking Unidos out of the running for samba champion of the year.