By their very nature, fireworks shows have exclamation points after their name, but tonight’s event in Oak Bluffs already has a few question marks.

Rain is the foremost question on the minds of people wondering whether to pack ponchos and umbrellas along with the blankets and baskets of fried chicken. Oak Bluffs firefighters in charge of the end-of-summer blockbuster are praying that the rain showers predicted hold off until the program is all done.

“If it looks like we’ll get dumped on, we’ll start earlier,” said Ken Davey, president of the Oak Bluffs firemen’s association which sponsors the annual event. Mr. Davey said the decision about tonight’s fireworks will be made by about 3 p.m. and then broadcast on WMVY radio (92.7 FM).

If the skies comply, the fireworks will get under way by 9 p.m. in Ocean Park and last for about 45 minutes, he said. “People spend a lot of time getting to the park,” he added. “We try to spread the show out.”

If there’s a downpour, the fireworks will happen Saturday night, leaving Mr. Davey and his crew to spend the night with the arsenal of Roman candles and other fireworks.

“Once it’s all loaded up, you can’t unload it,” he said. “We’d have to cover it with plastic, sit on the barge and babysit it all night long.”

Besides concern about rain, other questions hang in the air. In the wake of last month’s fireworks accident in Edgartown, Oak Bluffs fire chief Dennis Alley said he is taking special precautions this year.

The chief will station four firefighters on Ralph Packer’s tugboat, Thuben, which is outfitted with pumps and nozzles that can draw seawater. “This hasn’t ever been done before,” Chief Alley said, adding that he doesn’t want to see a repeat of what happened in Edgartown.

The Oak Bluffs fire department, though, is confident about the safety record of the fireworks firm, CR Pyrotechnic, which has offices in Salem, N.H. “The company we’ve used has never had an accident. That’s why we use them,” said Mr. Davey. “They’re very safety conscious.”

Getting ready for this year’s fireworks has been no easy job. The reason is Ocean Park, which was excavated over the spring to install leaching beds for the town wastewater system.

Until just a few weeks ago, there were serious questions whether the fireworks could even happen in Ocean Park. Officials were worried that so many people crowding the park would ruin the newly planted sod. Plus, problems with drainage and ponding water in the park raised even more questions.

But almost two weeks ago, wastewater project manager Bill Reich assured selectmen that contractors for the Ocean Park project felt the grass was ready to accept the thousands of people who will come for the fireworks.

This week, Mr. Reich said the park would be mowed by Thursday and ready for the fireworks. “We’re giving it a nice facelift and doing whatever we can to get ready,” he said.

One of the last details was making sure that electrical service is returned to the park — to power streetlights and to the bandstand, which is still being renovated. The town band will get a makeshift stage for the event aboard a flatbed trailer parked on the east side.

Despite assurances, parks commissioner Buddy deBettencourt is still worried that if the sod is ruined, the town will be stuck paying for it. Two weeks ago, he asked selectmen to obtain a written agreement from the contractor taking responsibility for the park even after the fireworks.

“I asked for it in black and white and never saw it,” he said. “I don’t know what’s going to happen if we use it. I just hope they don’t make a big scene.”