Workers clean oil off rocks and cobbles on the Refugio State Beach shoreline Tuesday. Officials will decide Thursday whether the beach can be reopened to the public on July 16. (Gina Potthoff / Noozhawk photo)

Thursday is the day State Park Superintendent Eric Hjelstrom will decide whether Refugio State Beach can reopen on July 16, which explains why the shoreline bustled with activity on Tuesday.

A helicopter began trips to and from ground zero of the May 19 oil spill just north of the park campgrounds, toting one dangling yellow container after another.

The metal boxes were filled with an oily sand-and-gravel mix, scooped up by a special excavator that had to “crawl” to the remote location near the bluffs.

Workers clothed in hazardous-material gear toiled to scrape hardened oil off rocks, and the tides weren’t helping with a second challenge — the cobblestones that keep getting recovered with sand as the ocean carries water on and off shore.

“There are so many moving parts,” said Hjelstrom, who’s in charge of state parks from Point Sal to El Capitan State Beach, which reopened June 26. “The further we come this way, the closer we get to ground zero.”

The initial cleanup is nearly complete, according to the Joint Information Center, which is in charge of the response for the spill off the Gaviota coast, along with Plains All American Pipeline, the oil company responsible for the leak of more than 100,000 gallons of crude oil (and the bill to fix the mess).

A helicopter ferries containers of oily sand and gravel as the cleanup of the Refugio oil spill continued Tuesday. (Gina Potthoff / Noozhawk photo)

About 96 percent of the affected shoreline and beaches have met the end-point cleanup goals for the initial stage, said Alexia Retallack, an incident command spokeswoman from the California Department of Fish and Wildlife.

As of Monday, nearly 500 personnel were still in the field, where wildlife rescue finished up its tallies of animals impacted by the spill.

Retallack said 42 of 57 captured affected birds had been released, with another 195 dead (although not all necessarily from the spill, she said). Crews recorded 62 live mammals captured and 106 dead.

A control group of healthy, unaffected birds will also be tagged and tracked for comparison data, she said.

“It’s part of the ongoing study to help determine long-term impacts,” Retallack said.

Hjelstrom said he didn’t put much stock in completion percentages, mostly because teams deemed a beach “clean” if any oil deposits still found there weren’t hazardous. It doesn’t mean 100 percent oil-free, per say.

Crews were focusing this week on a 300- to 400-yard stretch just south of Refugio to where the spill originated — three-quarters of workers focused on oil cleanup while the rest prepared aesthetics for visitors to return.

Equipment and workers were slowly moving out of the campground area, with Plains repaving and re-striping parking lots and roads that until recently held the weight of much heavier response vehicles and semi trucks than the asphalt was used to.

State Parks has been canceling campground reservations week-by-week and giving full refunds for spots that are typically booked up seven months in advance. Those who lost money on already booked flights, for example, can file claims with Plains.

“The second we reopen Refugio, it will be full,” he said. “I don’t want to (open) it prematurely.”

Richard Yukihiro, who led a team of about 100 rock-scrapers, said the responders trained to be on call for this exact situation hailed from some of eight offices across the state, with the closest near Ventura.

The helicopter ferrying oily sand and gravel was expected to be in operation through Friday or Saturday, or whenever the job is done.

Because heavy equipment will be moving soil around, the slow lane of southbound Highway 101 west of Refugio State Beach will be closed this week from Monday through Thursday, 9 a.m. to 6 p.m.

No one was quite sure what long-term monitoring of clean areas would look like — re-vegetation, backfilling sand, etc. — but Retallack said Unified Command would know more Thursday.

As for whether Hjelstrom would give the green light to open next week, he said he’s “optimistic.”

Noozhawk staff writer Gina Potthoff can be reached at gpotthoff@noozhawk.com. Follow Noozhawk on Twitter: @noozhawk, @NoozhawkNews and @NoozhawkBiz. Connect with Noozhawk on Facebook.