Worker killed, dozens injured and more missing after boiler explodes in a Mexico candy factory The explosion occured on the second floor of the factory in Ciudad Juarez The Dulces Blueberry factory produces gummy bears and jelly beans Forty were injured and several are still missing, authorities said One worker said the explosion was caused by a newly-installed boiler An explosion inside a candy factory in Mexico has killed one worker, injured at least 40 and several are still missing, authorities said. The blast, thought to be caused by a newly-installed boiler, took place on the second floor of the Dulces Blueberry factory in the border city of Ciudad Juarez on Thursday and caused the floor to collapse, injuring people working downstairs, according to one factory worker. Several workers are missing and could still be trapped inside said Ciudad Juarez Civil Protection Director Fernando Mota. Factory blast: Rescue workers help an injured worker after an explosion at the Dulces Blueberry factory in border city Ciudad Juarez, Mexico where one worker has died, another 40 were injured and several are still missing He said: "We're still searching the area to see if there are more dead." Authorities said the cause of the blast had not been determined but factory worker Ismael Bouchet said a steam boiler had been installed recently in the area. Bouchet, who works at the factory which produces gummy bears, jelly beans, peach rings and other sweets, said: "I was able to help five people who walked out of the building but as soon as they were out they went into shock and fainted." New boiler: One worker said that people could smell acid but thought it was normal as it was in a new area of the factory Devastating: Rescue workers help an injured worker after the explosion which is thought to have occurred on the second floor To the rescue: Paramedics assist an injured person as firefighters and authorities search for the missing in the rubble Mota said firefighters found a body inside and that six of the at least 40 injured are in a serious condition. Firefighters and rescue crews continued to search the building for more victims last night. Bouchet said people could smell acid in the area where the explosion occurred. He said: "Since the morning, several co-workers said there was a bad smell, that it smelled of acid and because it was a new area we thought it was normal." Wait for news: Distressed and anxious relatives and friends wait at the scene for any news of the missing workers Helping the wounded: Police stand next to an injured man after the explosion on Thursday Searching for the missing: Authorities and locals gather at the factory after the explosion, thought to have been caused by a newly-installed boiler Photographs of workers being helped by paramedics showed people with injuries that resembled chemical burns. The factory had no history of industrial issues. Mota told Milenio Television that the factories 'are usually very careful about sending out a message of taking care of their employees.' Dulces Blueberry employs 300 people and the candy is sent to a distributor based in El Paso, Texas, which lies across the border from Ciudad Juarez. Ciudad Juarez is a manufacturing hub and the assembly plants there employ many of its residents. Ripped apart: The damage to the factory in the border city of Ciudad Juarez, one of many in a free trade zone between the US and Mexico Emergency services work to contain the damage to the candy factory as paramedics and firefighters gather at the site Devastating damage: Debris lies outside the candy factory which produces gummy bears, jelly beans and peach rings The city is located on the border of American state Texas in the state of Chihuahua. The factory, along with others known as "maquiladoras," are in a free trade zone between the US and Mexico and employ over an estimated one million Mexicans. Ciudad Juarez has been named Mexico's most violent city and seen an increase in violence, as bloody battles between drugs cartels increase. Drug violence has transformed the region from a string of quiet farming communities into a lawless no man's land. At least 39 US citizens were killed in the city, with a population of 1.3million people, last year which had a murder rate above 3,000. All hands on deck: Authorities secure the area where workers were found with chemical burns at the factory which employs 300