I am a welder by trade and have worked on UST's and AST's over the last several years. In my experience it's almost always rushing and skipping procedures that lead to accidents. Three parts to cause explosion fuel,oxygen and ignition take at least one out of the mix and no explosion:-)
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On Dec 12, 2008, at 5:47 AM, "Don Johnston"  wrote:


Welding - Various Incidents Cause for Concern


CSB to Conduct Full Investigation of Causes of Catastrophic Fertilizer Tank Collapse at Allied Terminals in Chesapeake, Virginia - Issues Urgent Safety Recommendations Citing Hazard to Public from Welding Defects on Several Remaining Tanks

Chesapeake, Virginia, December 8, 2008 - The U.S. Chemical Safety Board (CSB) today issued urgent safety recommendations following last month’s collapse of a two-million-gallon liquid fertilizer storage tank at the Allied Terminals distribution facility in Chesapeake, VA, urging the company to take immediate steps to safeguard three other nearby fertilizer storage tanks from possible failure.

According to the text of the urgent recommendations which were unanimously approved by the Board and released at a news conference here today, "The potential for collapse of a tank poses an unacceptably high risk of causing substantial property damage or a number of injuries or possibly deaths among the general public."

The November 12 tank collapse seriously injured two contract workers, who were hospitalized. Two members of the public who tried to aid the injured men required treatment likely related to exposure to ammonia vapor from the released fertilizer. The fertilizer overtopped a containment dike and flooded sections of a nearby residential neighborhood, requiring ongoing remediation of the soil. At least 200,000 gallons of spilled fertilizer could not be accounted for, and some reached the nearby Elizabeth River, which flows into the Chesapeake Bay.

"The urgent recommendations we released today are designed to protect the safety of workers, the public and the environment," said CSB Chairman John S. Bresland. "We are calling on Allied Terminals to immediately reduce the hazard from the remaining tanks by lowering the maximum safe fill height and to retain a qualified tank engineering firm to assess the tanks’ safety. The independent engineering analysis should be conducted promptly, within 30 days, and its results provided to the city." The recommendations further call on Allied Terminals to develop and implement a corrective action plan for any identified deficiencies in the tanks.

CSB investigators concluded that the November 12 collapse of Tank 201, which contained an aqueous solution of urea and ammonium nitrate fertilizer, likely resulted from defective welds on the tank wall. The welding was performed in 2006 as part of a project to strengthen four fertilizer tanks that were constructed around 1929 by replacing vertical riveted seams.

"We found a number of welding defects where the modifications were made, including incomplete penetration of the welding metal into the joints," said CSB Lead Investigator Robert J. Hall, P.E. "These welding defects likely weakened Tank 201 and led to its failure when the liquid was raised to a level slightly below the tank's recommended safe fill height."

In the course of investigating the collapse of Tank 201 last week, CSB investigators determined that three other large fertilizer tanks, which were welded during the same time period, likely have welding defects similar to Tank 201—including insufficient reinforcement, porosity, and weld undercut—that could cause the tanks to fail. The closest of the three large tanks is located 250 feet from homes.

Investigators said that the level of risk could not be quantified based on their external visual examination of the welds and that a thorough, independent engineering analysis should be conducted, including testing to check for the internal defects in the welds.

Following the welding of the four fertilizer tanks, and before the collapse of Tank 201, Allied Terminals had hired HMT Inspection, a Texas-based tank engineering firm with offices worldwide, to examine each tank in accordance with existing industry safety guidelines for petroleum tanks. HMT’s report did not identify the welding defects that led to this failure; it recommended a "safe fill height" for each tank. However, the November 12 collapse of Tank 201 occurred while the tank was being filled to a level about three inches below the 27-foot safe fill height recommended by HMT.

Chairman Bresland said the remainder of the CSB investigation would focus on understanding why the welding defects occurred, why the tank deficiencies were not detected and corrected, and whether improvements are needed in the oversight of aboveground storage tank safety.

"At this stage in the investigation, it appears that no federal, state, or local agency has clear regulatory and enforcement responsibility for the safety of non-petroleum aboveground storage tanks," Mr. Bresland said. "Because of the hazard such tanks can pose, the CSB will examine whether additional safeguards are necessary at the national and state levels."

The CSB has identified similar oversight issues in other aboveground storage tank accidents. For example, the CSB previously investigated a sulfuric acid tank collapse in 2001 at the then-Motiva oil refinery in Delaware City, Delaware. Following that accident, which killed a contractor, injured eight others, and polluted the Delaware River, the Delaware state legislature enacted an extensive regulatory system for aboveground storage tanks, under the Jeffrey Davis Aboveground Storage Tank Act.

Mr. Bresland noted the outstanding coordination among the various local, state, and federal agencies responding to the spill, including the Chesapeake Fire Department, the Virginia Department of Labor and Industry, and the Region III office of the U.S. Environmental Protection Agency. Allied Terminals has been cooperating with the CSB investigation.

The CSB is an independent federal agency charged with investigating industrial chemical accidents. The agency's board members are appointed by the president and confirmed by the Senate. CSB investigations look into all aspects of chemical accidents, including physical causes such as equipment failure as well as inadequacies in regulations, industry standards, and safety management systems.

<image001.png> Watch Security Video of Release - http://hamptonroads.com/2008/11/about-200000-gallons-fertilizer-spill-still-not-recovered

Welders arrested in deadly warehouse fire


ICHEON, South Korea, Dec. 7 (UPI) -- South Korean police have arrested two welders suspected of causing a warehouse fire that left seven dead and five injured south of Seoul, officials said. After arrest warrants were requested for the welders, they were detained Saturday on charges of manslaughter by gross negligence on duty, police told Yonhap, the South Korean news agency. Firefighters Sunday were still putting out flames at the cold storage warehouse in Icheon, about 37 miles south of Seoul. Police said they found the body of one missing worker, identified as Lee Hyeon-seok, in the debris, bringing the death toll to seven, Yonhap said. The accident happened less than a year after a similar warehouse fire killed 40 people in Icheon in January. Like the previous fire, police said this one was worsened by malfunctioning firefighting equipment and blocked emergency exits.

http://www.firerescue1.com/fire-news/441417-south-korea-warehouse-fire-kills-6/

Man Dies in Miami Oil Tanker Explosion


NORTHWEST MIAMI-DADE, Fla. (WSVN) -- A contractor has died, and his son was injured after an oil tanker exploded.Late Thursday afternoon, Miami-Dade Fire Rescue crews reported to the scene at 8470 NW 68 St. where the tanker exploded while the two contractors hired by the E.M.C. Oil Corp. performed some work on top of a tank. Miami-Dade Fire Rescue explained that the father and son team were welding on top of the tanker when it exploded, spraying oil and debris everywhere, killing the father. It is believed that the deceased victim died from the flying debris. Richard Souza witnessed the explosion that was so strong it blew the cab of the truck open and sprayed a third man working nearby with oil. "I was working, then I saw a loud 'bloom'!" he said. "A pipe flew from their side to our side here." Miami-Dade Fire Rescue Lt. Arnold Piedrahita said the pair made a fatal mistake of not working on a tank filled to capacity. "If there is a combustible liquid
inside of a tank, regardless of the size of the tank, if it's full, it leaves no room for a vapor space," he said. "Vapors is what igntes and causes explosions. That's why, when these tanks are worked on they usually need to be full to create as minimum as a vapor space as possible. In this case, apparently, the vapor space was too great." The company recycles used oil and ships it. Fire rescuers could be seen treating the son on the scene from the back of an ambulance. He was sitting there conscious and talking with them. Family members were seen showing up to the scene. They did not speak to the media, but a little girl sitting inside a car could be seen crying. Miami-Dade police had cordoned off the area while they investigated.The subcontractors did not work directly for the company. It is not know how much experience or how often they've worked for this company before this fatal accident. A full investigation remains pending.

http://www.wsvn.com/news/articles/local/MI105589/

Regards
Kevin D Westwood
JOIFF Secretary
BP International Ltd Bld 'B' 2nd Floor, Chertsey Road, Sunbury on Thames TW16 7LN, UK

A simple reminder – always put SAFETY first and your return will be in keeping you and your company in the green.   Happy Holidays!