An artwork of uranium glass at the National Museum has set some visitors questioning if more information needs to be posted at the entrance.
The artwork, Crystal Palace: The Great Exhibition Of The Works Of Industry Of All Nuclear Nations, by Australia-based artists Ken + Julia Yonetani, features 31 chandeliers made of uranium glass beads. It is part of the Singapore Biennale 2013.
When lit by ultraviolet "black" light, the traces of uranium in the beads glow eerily green. The chandeliers are hung overhead in the black box basement gallery. Each represents a country which has nuclear capabilities and the size of the chandelier corresponds to the number of operating nuclear plants in that nation. The work was conceived as a response to the Fukushima nuclear disaster in Japan in 2011 and aims to explore people's fear of radiation, among other issues.
Uranium is a naturally occurring element with radioactive properties. Among its uses are as a colourant in uranium glass, a tint in early photography, in military weapons and to fuel nuclear power plants. The authorities had cleared the artwork for public display, after confirming that it emits only a small amount of radiation.
The wall text by the gallery turnstiles reads: "Caution: The gallery contains ultraviolet light. Visitors with health sensitivities, or infants, may wish to avoid this exhibit. Please do not touch the artworks."
There is no mention that uranium glass is used although the wall text inside the dimly lit gallery includes the detail that the work is "Metal, UV lights, uranium glass, 31 pieces, Various dimensions".
One Biennale visitor, Ms Yvonne Lee, was taken aback when told of the uranium glass artwork. The mother of three young children had taken her children to see other works in the Biennale, but had yet to visit the museum's basement gallery.
The self-employed worker in the real estate industry, 41, said: "I think organisers and artists have to be more prudent in such issues. There are people who are really sensitive or very particular about such things. They have to put up a more obvious and informative sign. Visitors can then make their own decision if they want to see the work."
Artist Jeremy Hiah, 41, visited the exhibit with his 11-month-old son last week. While he was not worried about any health concerns, he agreed that a sign indicating that uranium glass is used in the exhibit in the gallery would have been good.
Teacher Huang Lijing, 26, who also saw the artwork, said it would have been helpful if the sign outside the gallery had informed people that the exhibit was made of uranium glass so that visitors could choose not to enter the gallery. But she added: "I trusted that the organisers had ensured all this was safe."
When contacted, the National Environment Agency (NEA) said that the uranium in such glassware emits only a small amount of radiation which is below the exemption limit stipulated in the Radiation Protection (Ionising Radiation) Regulations.
The National Heritage Board, which runs the National Museum, had consulted the agency prior to the exhibit being brought in.
"Measurements carried out by the NEA showed that the radiation levels in the public access area in the vicinity of the exhibit is low. It is either similar to the background level or no more than 0.02 microsievert per hour above the background level," said the agency.
"As the annual radiation dose limit for the general public allowed for under the Radiation Protection (Ionising Radiation) Regulations is 1 millisievert per year, the exhibit poses no health risk to the general public viewing it. Symptoms of radiation sickness, for example, nausea, will only manifest when a person is exposed to high radiation dose of more than 1 Sievert (1,000 millisievert)."
One microsievert is 0.001 millisievert.
A spokesman for the biennale's organiser, the Singapore Art Museum (SAM), said that the work had been exhibited in countries such as Australia and Germany "with no issue and no advisory in place".
The spokesman said the artists submitted a radiological test certificate from Australia to confirm that the uranium glass used in the artwork was safe and did not require any protective measures for public display.
The museum is considering increasing the prominence of the advisory and including a note to say that the exhibit has been tested and is safe.
The artists who produced the work say that there is "absolutely no radiation danger" from the piece.
Julia Yonetani, 41, wrote in an e-mail response: "The radiation in the room is within normal radiation background levels. You can stand there for the whole exhibition if you like."
When told that the Crystal Palace artwork has been given the all clear by the authorities, art lover Yvonne Lee said she was still not sure if she would go and see it.
"Better safe than sorry," she said.
But at least one spectator's curiosity has been piqued.
"Now that you mention it, I'm actually intrigued to go and see it," said Ms Marianne Ha, 36, a teacher. "There is a certain amount of radiation in our environment anyway. You need to do a bit of research and then take a calculated risk."