A sign posted at the Expo Garden's Expo Axis warns people not to touch the facilities during electrical storms.

Organizers of Expo 2010 Shanghai on Wednesday dismissed a rumor that the Expo Boulevard is unfit to absorb lightning strikes, as the city's meteorologists warned of 15 more days of extreme heat and a possible typhoon this summer.

Heavy rainfall, coupled with lightning, is also forecast for later this week.

The Expo Boulevard, a 1,000-meter-long structure, is free of design defects and is properly installed with a lightning conductor, Ding Hao, deputy chief of the Bureau of Shanghai World Expo Coordination, said at a regular news briefing.

Safety concerns about the four-story building started doing the rounds when some visitors read signs at certain enclosed areas of the boulevard, asking them to stay away from the steel cables that connect the building's membrane roof and the ground in case of a rainstorm.

"It (the building) is safe no matter where you stand or what you lean on or touch," Ding said.

"The Expo Boulevard is a permanent structure, so the designers took all weather factors into consideration," he said. "All its membrane and cables are installed with a metal facility to protect it in the event of lightning."

The Expo Boulevard, which cost 3 billion yuan ($442 million) - roughly the combined amount to build the Beijing Olympics Bird's Nest National Stadium and Water Cube Aquatics Center - serves as a pedestrian path and houses several restaurants and shops.

Ding said not just the boulevard but all pavilions and open squares at the Expo were installed with lightning conductors.

A specific check was carried out on the lightning protection system early last month, followed by remedies and improvements, Ding said, adding that the system is now "operating properly".

Visitors can be sure they will not be struck by lightning, he assured.

Meanwhile, the city's Met department warned residents and visitors to prepare for another 15 days of extreme heat, when the mercury would soar above 35 C, and a tropical storm any time between now and August end.

The city has endured a total of five days of extremely hot weather since June 19, said Yuan Zhaohong, deputy chief of the Shanghai Meteorological Bureau.

Yuan said that the highest temperature in the city might reach 38 C to 39 C.

He said his bureau had yet to figure out how powerful the typhoon would be, "but going by history, tropical storms have hit Shanghai directly three times. And the department is gearing up for the worst".

The meteorologist said there will be a cloud cover in the city on Thursday, with the maximum temperature around 35 C.

An intense rainfall, coupled with lightning, will lash the city between July 9 and 12, he said, adding the temperatures will start rising again on July 13.

The city has said it has taken necessary measures to combat extreme weather.