HOUSTON _ one of the largest mobile cranes in the United States crashed to an oil refinery in Houston Friday, four people were killed and seven others injured, in the last several deadly accidents that have concerns about the safety of construction cranes.

The 30 stories high crane, which is able to be 450000 kg, decreased during Lyondell Basell in a refinery south of Houston about 2 hours, said Jim Roecker, the company vice-president for refining.

The massive, deep crane are on a smaller, yellow crane on the reasons for the refinery. The ambulances and fire brigade were on the outside.

The victims were in the field of crane, but officials are still not sure if they were on the crane or because of Roecker.

Three of the injured have been treated and released at the scene, said Houston Fire Department in the Deputy Head Omero Longoria. Two workers were seriously injured by helicopter Memorial Hermann-Texas Medical Center, the hospital and the two other workers were injured in a hospital transported by ambulance.

The crane from Deep South Crane & Rigging. Roecker has described as one of the nation’s largest mobile cranes, 90 meters with a height of 120 meters boom. Construction of the largest cranes term, but they are not mobile.

The crane was not planned to work until next week, but said that his Roecker engine idling after the ground gestoßen.

“It is a traumatic experience for all of us. We must concentrate on the health and safety of our employees,” said Roecker.

Deep South spokesman Margaret Landry has published a statement, the headquarters of the company in Baton Rouge, La., that he enquêtait “for determining the causes, to correct and to ensure that this type of tragedy does not not be repeated.”

Aerial photos of the site not immediately available, the airspace around Houston were limited, as President Bush was in town to the money the Congress candidate.

Near the scene of the collapse, Mattie Graham was with her husband, Horace workers Deep South Graham.

“I have to think about their families. He could be here today,” she said, gestures from her husband.

The refinery has Lyondell Basell about 3000 workers and 1500 workers under contract, Roecker. He said the entire staff at the plant were taken into account, and the plant is working normally.

Crane was certainly an additional test in recent months by an alarming number of deaths by crane in places like New York, Miami and Las Vegas.

In the city of New York, two crane accidents from March have killed nine people _ more than the total number of deaths of cranes over the past decade.

An analysis of the Associated Press in June found that cities and the Member States have very different rules for the construction of cranes, and some have no rules, chooses instead to the guidelines of the Federal from nearly 40 years that some experts will not to technological progress.

Texas has the country with 26 cranes from the deaths in the years 2005 and 2006, according to statistics from the federal government. Cranes, Texas, without a state or local control, although this task to the federal rule.

The crane at the refinery was delivered in parts and assembled on site last month. It came to remove the roof of the coking unit is so important, battery could from the inside, Roecker. Coker convert crude oil petroleum products.

This is Texas Crane Academy President Joe Bob Williams, of which the company confirmed grutiers for Lyondell, said it is unusual for these cranes to failure because of the number of people in their conversation.

“It is really strange for these cranes to all the questions, because there are so in the eyes,” said Williams.

Camera mounted to the work and Roecker said that the company hopes that the video with this camera to help determine what happened.

“With regard to what today we can succeed. At the moment we are concentrating on families and the victims,” said Roecker.

The refinery in Houston is one of the biggest for the treatment of high sulphur crude oil. The installation itself comprises some 700 hectares along the Houston Ship Channel in the city of Houston and Pasadena.

Texas is one of the 35 states that do not crane to secure a license. The earlier this year in Dallas, the city has found that eight of the 23 cranes are used to walk through the city market participants confirmed the orders.

OSHA standards require cranes to suffer annual inspections, but it is a self-mandate for the owners of cranes. The federal law requires that the review of documents kept, but not.

Roecker said the OSHA and other regulatory authorities, was from Friday to the accident.

Lyondell Chemical, a U.S. company, and the Dutch company Basell were rivals until they announced a $ 12 billion / 1 last July against one of the largest producers of chemicals.

On the chemistry, Lyondell product of ethylene, a precursor of crucial importance for a number of other chemicals and propylene oxide, which is also in the production of a wide variety of chemicals. Focuses on Basell Polyolefins, the types of plastic.