A few months after launching a pilot in Seattle, mobile fueling startup Filld hit a roadblock. On July 25, the Seattle Fire Marshall ordered the company to stop mobile fueling and handling of flammable liquids, Filld’s core business.

Filld stopped its on-demand gas service in Seattle and began negotiating with fire officials, one of many battles the company faces as it works to grow across the country in a tightly regulated space.

Silicon Valley-based Filld allows customers to schedule fill-ups using a mobile app. Filld employees drive mini gas tankers to customers’ vehicles on city streets, in parking lots, and in residential driveways, eliminating the need to stop at a gas station. Gas prices are competitive with neighborhood gas station rates, plus a delivery fee that ranges from $3 to $9. Filld’s service is available in Vancouver B.C., Washington D.C., Portland, and the San Francisco Bay Area.

If we can’t get on-street fueling resolved, then we won’t be able to do that in the City of Seattle which means that we won’t be able to provide that really beneficial service to the car-sharing companies and that’s a big deal.

Filld competes with Booster Fuels, another mobile fueling startup that launched in Seattle and relocated to Silicon Valley. Booster operates in a handful of cities and plans to launch in Seattle in 2019. It has an easier road ahead than Filld. Booster Fuels just needs authorization to fill up vehicles in parking lots, as it does in other markets. Filld is trying to convince regulators to allow it to fuel vehicles on Seattle streets.

Seattle is an attractive market for mobile fueling for a few reasons. It’s home to several car-sharing companies, all of which need efficient ways to fuel up the vehicles that they rent out. The number of gas stations in Seattle is also declining, according to Filld Senior Counsel Pierson Stoecklein.

But the future of the industry in Seattle depends on whether these startups and city officials can come up with an operating framework that allows for new fueling models while protecting public safety.

“We are in the process of working this through with a multitude of fire departments across the country,” Stoecklein said. “We’ve been able to, for example, successfully negotiate an excellent agreement with the District of Columbia which is no small task given that it’s the nation’s capital and has particularly unique public safety concerns.”

The Seattle Fire Department found Filld in violation of rules that govern the handling of flammable and combustible liquids, according to a stop work order obtained by GeekWire through a public records request. The fire department ordered Filld to stop “storage, handling, and/or use of flammable and/or combustible liquids” until the company obtains “a SFD issued Flammable and Combustible liquids operational permit.”

Filld is in ongoing negotiations with the Seattle Fire Department to reach a set of permit conditions that would allow the company to operate under its current business model. Of particular importance to Filld is the ability to fill up cars on Seattle streets, rather than porting them to a parking lot or facility. On-street fueling makes Filld a more attractive service to car-sharing companies, like ReachNow and Car2Go.

“If we can’t get on-street fueling resolved, then we won’t be able to do that in the City of Seattle which means that we won’t be able to provide that really beneficial service to the car-sharing companies and that’s a big deal,” Stoecklein said.

Stoecklein recognizes that despite its novel approach, Filld’s business relies on an old transportation paradigm: gas-powered cars. But he said Filld is working with companies developing technology that would allow for rapid, mobile electric vehicle charging. “We view ourselves as a fuel-agnostic energy delivery platform,” he said.

Electric vehicle charging is a priority for Seattle Mayor Jenny Durkan. Stoecklein says officials from her office have “been extremely helpful and receptive,” during negotiations. He’s optimistic that an agreement can be reached that “balances paramount public safety concerns but also allows us to deliver to prospective customers the benefits of our service.”