Some Kauai residents are anxious about two apparent fuel tanks that washed up about a mile apart on the Garden Island’s north shore.

Lori Stitt found one tank Friday morning at Makua Beach and could smell propane leaking from the rusty, barnacle-covered receptacle. Her boyfriend moved it away from the water and she called police.

On Saturday, she returned to find the over-4-foot-tall tank still on the beach with tourists lying just feet away.

"It needs to be removed," she said by phone. "I’m concerned for the public’s safety."

She warned the tourists, and one man told her he wasn’t worried because a pressure release valve on top of the tank was open.

Stitt took a photo of the upright tank and sent it to the state Department of Land and Natural Resources via Facebook.

About a mile west, a second tank was lying in the sand on Saturday, leaking its contents onto the ground, said Mark Soppeland, whose wife, Nancy, found the tank on Thursday.

The two tanks were on opposite sides of Haena State Park, and while neither had writing that could reveal their origin, some suspected they were debris from the devastating 2011 tsunami in Japan.

Mark Soppeland said since his wife first noticed the tank, someone had moved it from the water’s edge and apparently punctured it, possibly on a rock.

"It’s leaking some kind of foamy material," Soppeland said. "Nobody knows what’s coming out of it. It’s kind of a dangerous situation."

He also called police and was told that DLNR would be notified. A DLNR spokeswoman did not return a call seeking comment.

Soppeland said some authority should remove the marine debris, which he considers a threat to the public and the environment in a conservation district near Limahuli Stream.

He described the tank as the size of a 40- to 50-gallon water heater with a pressure release valve on top. He also said he could smell a gas coming from it earlier in the week.

On Saturday, it was tied to a fallen tree and cordoned off, but Soppeland felt authorities had not done enough.

"Nobody seems to be concerned about it," he said. "It’s a little disconcerting."

Sarah Blane, a Kauai County spokeswoman, said in an email Saturday that firefighters responded to a report of a tank washed ashore near Limahuli Garden and Preserve on Friday. After determining there was no immediate threat to the public’s health or safety, firefighters taped off the area and notified the state to have the tank removed.

She said the state will dispose of the debris.

"Until such time that the tank is removed, county officials urge the public to respect the boundaries of the caution tape," she wrote.

Blane said debris commonly washes ashore after a period of heavy rains.

"There is no evidence to support that the tank is Japan tsunami debris," she said, and referred further questions to the state.

Carl Berg, of the environmental group Surfrider Foundation, Kauai chapter, maintains the tanks are part of another wave of debris from the March 2011 Japanese tsunami that killed nearly 16,000 people.

His group received a grant last year to clean up marine debris and removed 25 tons along Kauai’s shorelines in a one-year period ending in September, he said. The grant came from part of the money Japan gave to the U.S. for tsunami debris cleanup.

Berg said there’s been a lull in debris from Japan since the summer, but more has been coming in this past week.

"We’re getting all the same stuff we got during the big peak of tsunami debris," he said. "Suddenly, here it all comes again."

Marine debris, he said, can pose a hazard to mariners and delicate reefs.

"For us, it means that stuff is still out there," he said. "It’s hazardous, and it’s still out there, and we’ve got to be cautious about it."

Berg said Surfrider volunteers were trying to confirm a report Saturday that a 15-foot-long tank washed up on shore near Larsen’s Beach on Kauai’s North Shore.