On October 17, 2007, a wiring employee came to a press brake to get more pieces from Employee #1, a press operator. Employee #1 turned and put down a piece, collapsed to the floor, and experienced convulsions. The wiring employee panicked and asked the laser operator for help. The laser operator cleared the area. As he stood from the kneeled position, he also became lightheaded and lost consciousness momentarily. All employees were then evacuated by the shift supervisor per their emergency action plan.
Six (6) liquid argon tanks were being stored on the INSIDE wall of the 47,000 square feet building, approximately 55 feet from the press brake department, with one (1) tank supplying the building’s system line for welding operations throughout the facility. Two (2) other employees in the immediate area of the argon tanks also experienced lightheadedness and were transported to the hospital with the aforementioned as a precautionary measure.
The Technical Sales representative from National Welders responded to the scene and tested for oxygen deficiency. He tested the system line at 100 psi, which revealed no leaks, and suggested that the tank connected to the supply line released gas from the relief valve due to back pressure from the line.
The Manufacturing Engineer confirmed that two (2) tanks were found leaking. One of the tanks was completely emptied over the span of a week, while the other was still leaking three (3) weeks from the incident.
Each tank has the capacity to hold 471 lbs of liquid argon. The Fire Department and Emergency Medical Service cleared the scene for resumption of occupancy after finding no oxygen deficiency present. The company removed all tanks with argon immediately after the incident. Four tanks were placed along the outside wall and two leaky tanks were put approximately 70 yards from the building.
The company reconnected the tank to the supply line by drilling through the wall. They also ordered oxygen sensors to be placed throughout the facility and connected them to the company’s alarm system.
SECTION 5307—COMPRESSED GASES NOT OTHERWISE REGULATED
5307.1 General.
Compressed gases in storage or use not regulated by the material-specific provisions of Chapters 6, 54, 55, and 60 through 67, including asphyxiant, irritant, and radioactive gases, shall comply with this section in addition to other requirements of this chapter.
5307.2 Ventilation.
Indoor storage and use areas and storage buildings shall be provided with ventilation in accordance with Section 5004.3. Where mechanical ventilation is provided, the systems shall be operational during such time as the building or space is occupied.
Exceptions:
1. A gas detection system complying with Section 5307.2.1 shall be permitted in lieu of mechanical ventilation.
2. Areas containing insulated liquid carbon dioxide systems used in beverage dispensing applications shall comply with Section 5307.3.
5307.2.1 Gas detection system.
In rooms or areas not provided with ventilation in accordance with Section 5307.2, a gas detection system complying with Section 916 or, where approved, an oxygen depletion alarm system, either of which initiates audible and visible alarm signals in the room or area where sensors are installed, shall be provided.