WWII bomb found in Upper Bukit Timah likely to contain about 47kg of explosives

SINGAPORE - The World War II bomb triggering the largest evacuation exercise involving such a relic here was likely dropped during the Battle of Bukit Timah in February 1942, the final stage of Singapore’s fall to the Japanese.

History buffs told The Straits Times on Monday that

the bomb uncovered last Wednesday at a condominium construction site

off Upper Bukit Timah Road likely contains about 47kg of explosives, sufficient to destroy a block of flats.

The 100kg relic was probably a high explosive bomb deployed by an aircraft supporting the Imperial Japanese Army on the ground, they said.

When dropped from a height by a plane diving at a speed of 320kmh, bombs of that weight can easily penetrate several metres underground, said Dr Euan Graham, a senior analyst at the Australian Strategic Policy Institute.

A high explosive bomb can either explode on impact, or contain a timed fuse that detonates the bomb after some time, which can cause more damage to buildings as it would penetrate roofs and kill everyone inside a building, said war historian John Kwok.

But due to various factors, the fuse of a bomb can fail to detonate the explosive.

Dr Kwok said: “For some reason or other, such remains from the war were missed during the post-war clean-up. They would be discovered again when the area is disturbed during construction projects.”

There is a chance that the 100kg bomb can become more dangerous over time due to degradation, according to Mr Mike Yeo, the Asia correspondent for United States-based defence magazine Defense News, who has written about the Pacific War.

Citing a blaze in 1967 involving exploding old bombs on a US aircraft carrier that killed 134 people, he said: “The explosives were unstable, so when they caught fire, the bombs exploded in a much shorter time than they were actually designed for.”

Dr Kwok, who co-founded consultancy Total Heritage, said it is essential to evacuate areas close to the site as a safety precaution.

He said: “To give a comparison of the damage a WWII-era bomb can cause, in Limburg, Germany, in June 2019, a 250kg bomb accidentally exploded in a farm field, creating a crater 10m wide and 4m deep.

“The bomb in Singapore is much smaller, but it would be able to cause a crater at the site, and the shockwave can cause windows to shatter and doors to break, sending shrapnel and broken glass like flying projectiles that can injure people.”

The bomb is not the largest to have landed in Singapore. Bigger bombs weighing up to 250kg were dropped by the Japanese during their three-month Malayan campaign.

Based on records, aerial explosives such as the recently discovered one were the most common aircraft bomb type, with more than 6,000 dropped during the Malayan campaign, said Mr Yeo.

Dr Kwok said: “We do know that the Japanese Imperial Army at the time did not bomb every part of Singapore. The focus of their air raids was, at the time, Singapore City, the docks, the airfields and areas where the British forces dug in to defend Singapore. Bukit Timah was one such area.”

The recently unearthed bomb was found at the site of the main Japanese advance on Bukit Timah Hill in 1942, when the Japanese took over the strategically important hill and the British unsuccessfully launched their only serious counterattack during the invasion.

Dr Graham said: “A lot of men died on both sides. It was a kind of climax for the Malaya campaign, and the British were fighting desperately to try to hold that hill and the Japanese were fighting desperately to take it. It’s hard to imagine now because it’s a peaceful area.”

Among those who fought for Singapore there was the Dalforce, a volunteer army of Chinese locals given very little training, he noted.

Experts expect more of such bombs to be uncovered in other parts of Singapore.

Mr Yeo said: “There have been several previous instances of construction work uncovering such unexploded ordnance, and it is very likely that this will not be the last such unexploded bomb to be found in Singapore.”

Should members of the public come across war relics, they should report them immediately to the police, he added.