Dozens of times during the summer as the rain picks up here on the prairie, suddenly, there’s a flash.
“You can be sitting there watching it, enjoying the night and all the sudden, boom!” said Kyle Chernenko, a resident of Grassy Butte.
Chernenko has watched these prairie thunderstorms his whole life from his home in North Dakota’s Bakken oil patch. He’s the volunteer fire chief in this small town.
“You hear the crack and area light up and you’re like, ‘Oh boy,’” he said. “You’re just sitting there waiting for it. All the sudden, the phone goes off and you’re like, ‘Oh man, now I’ve got to go to work.’”
He was already fighting a wildfire this summer when a thunderstorm rolled through, and he got that dreaded phone call. Another fire had broken out, this time at a disposal site for wastewater. This salty water is a byproduct of producing oil, and is stored in tanks before it’s injected back underground.
Lightning struck the facility, burning up 18 storage tanks and causing a huge spill of wastewater and oil.
“When it comes to big oil fires like that, it takes a lot of foam and a lot of water,” Chernenko said.
North Dakota doesn’t track how often lightning hits these wastewater sites. But the emergency manager in McKenzie County estimates it happens here four or five times a year.
Though no oil-rich state has rules on the books requiring these sites to install lightning protection equipment, that doesn’t mean they aren’t paying attention.
It’s an issue that concerns Jeff Thompson. The hazardous chemicals officer with North Dakota’s Department of Emergency Services is also a volunteer firefighter.
“I think we go to just as many lightning strikes on hay bales as we do tanks,” he said. “But it’s not as big of a deal to everybody because it’s not a big glow in the sky. There’s not a big dark cloud, so it doesn’t seem as big perception-wise to the public.
These saltwater sites, more so than other oilfield facilities, can cause the most harm when they’re hit.
Here’s what often happens: Saltwater tanks tend to be made of fiberglass and placed right next to metal tanks storing oil. Metal tanks are usually grounded, but it’s trickier to safeguard these fiberglass tanks, which often have small metal parts. Those little pieces each need to be properly bonded and grounded.
“It’s like a chain with the weakest link,” said Benjamin Hearst with Petro Guardian, a company that sells lightning protection equipment for the oilfield. “If you don’t have strong links in your entire chain, you can have a tank fire.”
Petro Guardian is based in Louisiana, but it sells equipment to sites in a number of oil fields, including in the Bakken.
“I’ve seen sites where steel tanks have launched like bottle rockets,” Hearst said. “I’ve seen completely melted and burned fiberglass tank batteries. I’ve seen pieces of tanks in people’s yards.”
Fires can happen when the gases inside a tank ignite. Flames may spread to surrounding tanks, erupting in a fireball. All it takes is a tiny spark, Hearst said.
Some companies, like White Owl Energy, take it upon themselves to try to alleviate this risk.
On a recent summer day, engines rumbled in a line of a dozen trucks hauling wastewater from nearby oil wells to one of the company’s facilities near New Town. They were waiting to offload the water into a system that’ll send it into one of 14 tanks.
Whenever workers notice lightning, the scene here changes.
“We’ll shut down the plant if needed during a storm just to minimize the safety risk to employees,” operations supervisor Steve Willis said.
The staff of White Owl Energy has seen other facilities struck by lightning and learned from those incidents. They just upgraded the New Town site’s lightning protection a year ago.
“We’ve got lightning rods up on top of all our tanks, our light poles, our pump buildings, and those are all grounded to the ground,” Willis said.
This equipment cost more than $50,000. A worthy investment, he thinks.
But as those who work at these facilities know, sometimes lightning still strikes wastewater sites, even when they think they’re protected.
Thompson with the Department of Emergency Services is looking into why these sites are targets, and whether they’re disproportionately hit.
“That’s where you have to look at historical data,” he said. “Did they set up on a ridge that’s just prone to lightning strikes, where you can spend all kinds of money and you’re probably still going to get hit?”
He’s not looking to come up with new regulations for the industry. But he wants clear data to show oil- and gas-related companies how to make the oilfields safer -- and to find a way to avoid spills that could have been prevented.