Ordinary key rings — the kind found in pockets and purses — figured large in triggering a 2016 toxic fog that sent more than 140 Atchison, Kan., area residents to hospitals, according to a federal board’s detailed account of the incident.
The problem: two such spiral rings were missing, said the report by the U.S. Chemical Safety and Hazard Investigation Board.
MGPI Processing used metal key rings to help secure the pipelines that filled the massive chemical storage tanks at its Atchison facility. A padlock was looped through a key ring on each side of a cap covering each fill line’s valve, locking the cap in place.
On Oct. 21, 2016, an MGPI employee removed the padlock securing the line to the company’s tank for sulfuric acid, said the account released Wednesday. A delivery driver from Kansas City, Kan.-based Harcros Chemicals was there to unload a tanker full of sulfuric acid.
According to the report, two other fill lines also were unlocked because each was missing one of its key rings. Instead of one unlocked line, there were three. Also, the plant employee had left after unlocking the correct line.
The driver, expecting to find only one unlocked line, connected to the first he saw.
It was the wrong one.
As his shipment poured into a tank already 90 percent filled with sodium hypochlorite, or concentrated bleach, the incompatible chemicals burst from the tank and “a cloud containing chlorine gas and other compounds” quickly spread.
“The cloud impacted workers on site and members of the public in the surrounding community,” the board’s report said. “Over 140 individuals, including members of the public, MGPI employees, and a Harcros employee, sought medical attention; one MGPI employee and five members of the public required hospitalization as a result of exposure to the cloud produced by the reaction.“
The Chemical Safety Board report said both companies have reached what it called informal settlement agreements with the federal Occupational Safety and Health Administration in May. It did not disclose terms of those agreements.
MGPI Processing said Wednesday that OSHA had issued citations to both companies leading up to the settlements. It also said the Environmental Protection Agency continues to investigate the incident.
Harcros officials could not be reached for comment.
The Chemical Safety Board report cited various shortcomings at both companies that contributed to the incident and to the seriousness of injuries. It also cited changes the companies have made since then and recommended actions for other companies that handle large amounts of chemicals.
Nearly 40 million tons of chemicals are delivered in similar fashion every 8.4 seconds on average across the United States, according to the report. Not all of them are potentially reactive like the chemicals involved in the Atchison incident.
But enough reactive chemicals are delivered to sites that even simple tasks such as connecting a hose to the correct valve can have serious consequences when things go wrong.
Several residents and an employee were overcome by fumes from a 2015 unloading incident in Florida involving the same two chemicals, the report said. In that case, a driver mistakenly pumped sodium hypochlorite into two tanks holding sulfuric acid, the opposite of the Atchison accident.
The board’s report cited eight inadvertent mixing incidents since the start of 2014, not counting the Atchison accident. Among the eight, 44 people suffered injuries, with two requiring hospitalization, and 846 people were evacuated.
Wednesday’s report included 11 recommendations for companies that receive chemical shipments as a way to lessen the odds of further accidents.
Among the recommendations: companies should work together to choose unique fill line connections for each chemical — varying their size, shape or color — so a driver’s nozzle will fit or match only the correct fill line for the chemical being delivered.
MGPI Processing and Harcros have done that among other changes since the incident.
“Harcros has worked with MGPI (Processing) to select uniquely shaped transfer equipment for sulfuric acid to make it impossible for drivers to connect another delivery hose to that line,” the report said.
The final report follows the board’s preliminary report, which was released in April.
MGP Ingredients, which owns MGPI Processing, issued a statement that said the company has worked with the board and other government agencies’ investigations.
“We have worked hard this past year in providing a safer environment for all,” the statement said in part. It made changes immediately after the incident, hired Burns & McDonnell for a review of its chemical unloading and storage methods, and took other measures.
The Chemical Safety Board does not take action against companies or issue penalties. It did not make any recommendations to OSHA or the EPA, though it can do so.
“OSHA and EPA were involved in the (board’s) investigation. They conducted or are conducting separate and independent inspections and enforcement activities,” said Lucy Tyler, a board investigator.
In piecing together what happened in Atchison, the Chemical Safety Board cited several deficiencies in the companies’ training practices and other measures intended to prevent accidents and to minimize the harms when accidents happen.
It also found that both individuals had failed to act as their companies’ procedures required. The two also offered different accounts of a key moment.
The plant employee told investigators that he unlocked the correct fill line, pointed it out to the driver and that “the driver acknowledged the location,” the report said. “The driver, however, reports that the operator did not point out the fill line.”
Then, the plant employee left before the driver connected to the fill line, which the report said “did not align” with his employer’s procedures in “two critical ways.” Instead of leaving, he was supposed to watch the connection being made to ensure it was to the correct line, and he was supposed to be the one to open the valve to allow the chemical to flow.
Others at the plant, the report said, told investigators that “it was their practice to have truck drivers open the fill line valve.”
The driver, alone when he connected to the first unlocked fill line he found, also was responsible for ensuring the correct connection was made, the report said. But instead of connecting to the sulfuric acid tank’s line, he connected to the concentrated bleach tank’s line that was missing one of its key rings and therefore unlocked. A key ring also was missing from the fill line for a tank holding acetic anhydride, the report said.
It mattered, said the report, that fill lines for five tanks were positioned close to each other. Only 18 inches separated the correct line from the one the driver mistakenly used.
It mattered, the report said, that the nozzle from the truck’s hose would fit any of the fill lines, that only one of the five fill line valves was marked to identify the chemical it should receive, and that markers on the the fill lines themselves were far enough from the valves to make it more difficult to follow each to the correct valve.
“Had MGPI placed pipe markers or identification tags on all the fill line connection points (or at the very least, on the sodium hypochlorite fill line connection point), it might have been immediately obvious to the driver that he was connecting the discharge hose to the incorrect fill line,” the report said.
As for the driver, he too was responsible for ensuring that he connected to the right fill line, the report said. It noted that he opened the value and went to the cab of his truck. Had he stayed at the valve, it said, he could have turned off the flow quickly once the odorous mixture began.
Harcros said the driver could monitor the situation from the cab, according to the report.
Harcros, however, failed adequately to train its driver about “a pneumatic emergency shutoff switch” in the cab of the truck. It said training logs indicated the driver knew about the location of the valve, but he did not use it.
Instead, he tried to reach the valve first from one side of the truck and then from the other. He “ was overwhelmed by the gas,” the report said.
“Had Harcros provided adequate training, such as by requiring its drivers to practice locating and triggering the emergency remote shutoff in simulations, the driver might have attempted to trigger the emergency shutoff switch, rather than attempt to close the valve at the back of the trailer,” the board’s report said.
This article was updated to correct the name of MGPI Processing, which had been incorrect in the earlier version.