NTSB releases preliminary report on 133-vehicle pileup that killed 6, injured dozens
Investigators found that I-35W was treated for ice 44 hours before the crash
Fort Worth Star-Telegram
FORT WORTH, Texas — The company responsible for preventing ice on the Interstate 35W TEXPress lanes applied a brine solution to the roadway 44 hours before a 133-car pileup that killed six people during a winter storm Feb. 11, according to a NTSB preliminary report released Wednesday.
The company, North Tarrant Express Mobility Partners, is responsible for the upkeep of toll and non-toll lanes at the site of the crash, which occurred on the southbound TEXPress lanes between Northside Drive and 28th Street. Company officials said Wednesday afternoon that they believed the anti-icing brine should have still been working, even though nearly two full days passed between the time it was applied and the series of crashes.
In its report, the National Transportation Safety Board, an independent federal investigation agency, cautioned that the contents of the document were preliminary and could be supplemented or corrected during the ongoing investigation. A final report is expected later this year or in early 2022.
"In the days before the crash, the area had experienced 36 consecutive hours of below freezing temperatures," the report states. "In anticipation of forecast freezing rain and sleet, NTE Mobility Partners Segments 3 (NTEMP S3) reported that they had pretreated the traffic lanes with an Ice Slicer NM brine solution. The solution was applied to the two southbound toll lanes in the vicinity of the crash on February 9 at 10:12 a.m."
The crash occurred about 6 a.m. on Feb. 11.
Ice Slicer NM, also known as Ice Slider CB, is a commercial deicing and ice-prevention product made mostly of sodium chloride. It is widely used by highway crews as a replacement for white salt, and can be used on roads as a granular product, or in a liquid brine.
The report also noted that, about four hours before the crash, the weather station at Fort Worth's Meacham Airport three miles north of the crash site reported light freezing rain and mist.
At 3:40 a.m., a dynamic message sign operated by NTE Mobility Partners began to display a message "ICY CONDITIONS EXIST. PLEASE USE CAUTION" in response to a crash about five miles to the north, at I-35W and Western Center Boulevard, according to the report.
NTE Mobility Partners confirmed that the area where the pileup occurred was last treated with the anti-icing brine solution about 44 hours before the incident.
Robert Hinkle, NTE Mobility Partners spokesman, said the company's crews continually monitored roadways for ice formation in the hours before the pileup, and "the crews monitoring the roadways detected no icy conditions at the accident site."
Hinkle also said the brine solution should have still been effective at preventing ice 44 hours after it was applied.
"The Ice Slicer NM brine solution NTE used is a high-quality brine and is effective for up to 72 hours," Hinkle said in an email. "Because no rain occurred between the brining treatment on February 9th and the accident, the brine would remain on the roadway for the period of its intended use."
The NTSB report also disclosed for the first time that two of the six people killed in the crash had left their cars and were pedestrians on the highway when they were struck. Dozens of other motorists were injured and, in all, 36 people were taken to hospitals, many crowded into ambulances with others who were wounded.
NTSB "is conducting a focused investigation to examine the road treatment strategies used to address the freezing conditions," the report states.
NTE Mobility Partners, the Texas Department of Transportation, the Fort Worth Police Department, the Fort Worth Fire Department and the Metropolitan Area EMS Authority are playing a supporting role in the probe, NTSB says.
The company that makes Ice Slicer, Desert Mountain Corp. of Kirtland, N.M., says that while Ice Slicer can be used in a liquid brine to prevent ice from forming, it should be used in solid form to attack ice that has already formed.
"With chemical liquids such as brine, you are applying 23% chemical and 77% water," the company explained on its website. "With solid applications you are applying 100% active material. The current practice of simultaneously applying liquid and solid deicers is also proving to be a very effective deicing method. In a nutshell, where 'dilution' is an issue, such as in heavy precipitation, solid application is the best approach."
In the pre-dawn hours of Feb. 11, witnesses on northbound I-35W in the same area reported that a sheet of black ice had formed on the road, making travel treacherous. Many passers-by shot video of the cars and 18-wheelers careening out of control and crashing into each other, all trapped between the toll lanes' concrete barriers — and much of that footage went viral on social media.
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