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Engine 31 immediately requested Battalion Chief 2 (BC2) to respond with a combustible-gas instrument (CGI) to verify their suspicions. Upon entry with the CGI, the lower explosive alarms sounded immediately. The structure was evacuated as BC2 requested the Lakeland Water Department and TECO, the local gas utility. TECO arrived promptly and was briefed. The initial TECO representative was unaware of any reported breaches in the gas-distribution system and was in disbelief that methane could be in the municipal drinking water. Engine 31 attempted to open a nearby hydrant and immediately experienced difficulty as the water system was uncharacteristically charged with high pressure. Once the hydrant was opened, the CGI immediately alarmed when held near the flowing water. It was apparent that the municipal water supply was contaminated with pressurized natural gas from an unknown source. City of Lakeland Utilities assisted in searching for the cause of the contamination as the 911 center continued handling multiple calls for “smell of gas.”
A citizen approached fire units and reported a large raised area of asphalt in the roadway two blocks away. BC2 investigated and found an entire intersection raised approximately 10 feet. The area was free of standing or bubbling water that would have indicated a water line break; however, an obvious odor of ethyl mercaptan was found in the intersection. BC2 established command and immediately requested the response of Battalion Chief 1 (BC1), Engine 11, Rescue 32 and Rescue 62. The large “bubble” of roadway continued to grow, creeping laterally down the length of the street. Due to the geographic size of the event, East and West Divisions were established. Homes surrounding the leak site were evacuated by fire personnel.
TECO determined the leak was likely to be a four-inch line beneath the roadway. TECO’s response team met with command and determined that the appropriate action to take involved mechanically digging up the roadway and placing crimps in two locations as the gas could not be remotely isolated. This still left a huge question unanswered: How was leaking gas contaminating the municipal water supply?
Multiple “smell-of-gas” complaints came into the 911 center – and all the “wrong” pieces began to come together. A typical gas leak may require evacuation of the area directly surrounding the leak as the gas company repairs the broken line. The evacuation is usually isolated and brief, with a defined area identified. These are our “routine” calls, but this incident was anything but ordinary. The area involved could not be isolated or defined, as the entire municipal water system was likely tainted with gas. Removing electrical power to the area was considered as a means to prevent ignition sources in multiple homes with the potential for gas-related fires. It was ultimately decided that the power would remain on as citizens would likely light candles for light without power.
The County Emergency Management Team was used as a resource to inform the public about the event. A reverse 911 was initiated to the area instructing residents not to use faucets, toilets or other water devices and eliminate ignition sources. Shelter-in-place was used for residents outside the immediate area of the leak. The Utilities Department was instrumental in attempting to isolate the flow of water to and from the area. TECO response personnel requested fire protection during excavation efforts as the backhoe removed asphalt to reach the leak. Supply apparatus worked with the Utilities Department to find water outside the contaminated area. Hydrants were opened and checked with a CGI. The soil was removed, revealing two iron pipes intersecting at a 90-degree angle. Crimps were placed on both sides of the leak to stop the flow of gas.
A close inspection revealed that a lightning strike had fused the gas distribution line to the municipal water line lying above it. Minimal water leaked from the pipe as the pressure of the natural gas line exceeded the municipal water pressure, ultimately forcing the gas into the water system. Lakeland Utilities flushed the water system to eliminate any residual gas. The incident lasted just over five hours and affected 1,200 residents.
Many lessons were learned:
• The Incident Management System (IMS) was successfully used as multiple agencies were needed to assist with mitigation.
• Shelter-in-place versus evacuation is never an easy decision. Sheltering-in-place worked in this incident only due to the time of day. The Polk County Sheriff’s Office attempted to call residents with the reverse 911 message, but few of the numbers were valid as residents have moved or are using cell phones as opposed to using landlines.
• Typical municipal hydrants may be unusable for suppression due to contamination. Can you imagine flowing a fire stream infused with natural gas? Formulate contingency plans for water supply in case hydrants become unavailable.
• Notify the health department of potable water contamination.