Santa Maria (Brazil), Jan 31 (IANS/EFE): The toll from last weekend's fire at a discotheque in this southern Brazilian city rose to 235 and 143 people remain hospitalized, authorities said Wednesday.

Three days after the deadliest blaze in Brazil in the past 50 years the number of fatalities keeps rising because many of the people who initially did not need medical attention are starting to suffer the effects of respiratory poisoning.

On Tuesday alone, 22 people were admitted to hospitals for treatment.

They are people who emerged apparently unhurt from the Kiss nightclub in Santa Maria but who later began to experience symptoms like shortness of breath, difficulty breathing and fatigue, all of which are typical of chemical pneumonia and which can arise up to five days after inhaling toxic substances.

Chemical pneumonia, or aspiration pneumonitis, is the non-infectious inflammation of the lung caused by aspirating or inhaling irritants.

The number of injured people in critical condition remains at 75, health officials said.

Preliminary investigation of the tragedy indicates that the fire began when one of the members of the Gurizada Fandangueiras band ignited fireworks, the sparks from which came in contact with the flammable foam used as acoustic insulation on the disco's ceiling.

In addition to the use of a prohibited item within an enclosed establishment, the panic that spread through the crowd due to the heavy output of smoke - along with the decision by security guards to close the doors to prevent the public from leaving without paying - contributed to the heavy loss of life, firefighters said.

Police Monday arrested four of the people under investigation for possible responsibility in the tragedy, among them the two owners of the disco and two of the musicians who were on stage when the fire started.