The advisory would come first; then around July, McClure and the team expect to complete a combined investigative report on the Valley Center incident and another Barton Solvents fire in Des Moines. The Iowa fire involved a portable tank being filled at a warehouse, McClure said.
The advisory would target a class of flammable liquids that give off ignitable vapors even under normal conditions and build their own static charge.
The product in the tank that exploded had the brand name Special Naphtholite 66/3, more commonly referred to in the industry as VM&P naphtha. McClure described it as a common solvent that has been used in the paint industry for years.
Barton Solvents' customers include paint manufacturers and printing and aircraft-related businesses, Casten said.
Besides recommending that nitrogen be used, the advisory would also outline other safety practices including using anti-static additives in the "bad-actor" solvents and slowing the velocity at which liquids are pumped into tanks, McClure said. If liquid goes into a tank at too high a rate, it can increase static, increasing the likelihood of an explosion.
"If you do any one of them, you could greatly lessen the chance of an event like this," he said.
In the state investigation, Higday reported that Barton officials said they didn't use anti-static additives because customers would have to agree to the practice and because the absence of additives had not caused a problem.
The state's investigative report also raised the question of whether the pump being used to transfer solvent from a tanker-trailer into the storage tank was pumping too fast.
Casten, the Barton Solvents president, said additives aren't widely used and said the pump speed fell within guidelines.
The state report noted that the experienced Barton Solvents dock foreman who was filling the tank said he "didn't do anything different" that day. Barton Solvents has owned the site since 1979 and has operated in Valley Center without a similar incident.
County tank inspections
Because of the explosion, Sedgwick County would probably consider requiring a nitrogen blanketing system for any new, similar facility, said Sedgwick County Fire Marshal Tim Millspaugh.
Millspaugh, Casten and other officials -- including Bob Benedetti, a flammable-liquids expert with the National Fire Protection Association, which sets safety codes and standards -- agreed that nitrogen blanketing is not widely used largely because of the cost. Casten said the cost is "six-figure" per facility for equipment and installation.
But even if the cost exceeds $100,000 a year, "it's better than a 20 or 30 million-dollar fire every 10 or 15 years," Millspaugh said. "If I were a plant owner, that's the way I would look at it."
Casten declined to discuss damage figures.
This year, the county's fire department plans to train at least two people to inspect above-ground storage tanks in the county fire district, Millspaugh said.
"That's not to say that an inspection would have prevented the Valley Center thing," Millspaugh said.
Still, inspectors could check for such features as grounding equipment to help prevent fires and explosions and dikes to contain material, he said.
The county would not inspect in Valley Center because the city has its own fire department and is outside the fire district, Millspaugh said.
Valley Center would rely on the state fire marshal's office for tank inspections, said Kristine Polian, the city clerk. The city's fire department doesn't have the personnel and expertise to do the job, she said.
The state fire marshal's office has said it never inspected Barton' 43-vessel tank farm because it lacks staffing and the expertise.
Next step for Barton
Before the explosion, Casten said, Barton Solvents thought it had enough safeguards in place, including adequate grounding. Grounding is designed to safely divert an electrical charge.
Using nitrogen blanketing would be the company's next step, Casten said. The company is constructing a nitrogen system at its 31-tank facility in Kansas City, Kan.
"We want to install one and see how it works," he said.