SINGAPORE – Emissions and intermittent odour can be expected from ongoing soil treatment works at the former Kallang Gasworks, but they do not pose any adverse health risks to the nearby community, said the Singapore Land Authority (SLA).
Authorities described on Monday (March 23) measures put in place to mitigate odours and noise caused by treatment works at the site along the banks of Rochor River, after some residents complained that it caused them to have medical problems like headaches and flu-like symptoms.
SLA said there are 3,550 residential units within a 100 metre radius of the work site. It received 139 pieces of feedback during the first phase of soil remediation works between February and June last year, most of which was about odour issues.
Following this, a new treatment system was installed that would remove odour-causing compounds through vapour treatment, with residual odours further treated using activated carbon. Filters of the activated carbon units were also changed more frequently.
To suppress noise, old generators were replaced and additional soundproofing was installed around noise generating equipment. The National Environment Agency has assessed that both noise and emission levels at the site are within its permissible levels, said SLA.
The second phase of remediation works began last December. Since then, there have been 25 pieces of public feedback, it added.
Some residents told The Straits Times the situation has improved compared to the first phase of works, when they could see dark-coloured fumes emanating from the site.
The smoke discontinued after a few months, but a group of residents said noxious odour and noise pollution continue to be a problem, especially when winds blow the fumes into nearby homes.
A resident living at Blk 468 at Crawford Lane who gave his name as Mr H Teo, likened the smell to a mixture of liquefied petroleum gas, tar and asphalt.
Construction worker Hardeep Singh, 35, who tests the soil at the roadside next to Crawford Street – in front of the boarded up Kallang Gasworks site – said the stench smells like oil and gas.
“I had head pain while working because of the strong smell, so my supervisor told me to wear a filter mask,” said Mr Singh.
Mr Teo, 36, said he suffers frequent bouts of throat inflammation, teary eyes, sneezing, and runny nose when he gets hit by the smell. He also gets hives on his arms and face. The finance professional takes antihistamine to reduce the symptoms, and shuts all the windows in his flat.
“I feel bad for the rental flats nearby. Many of the houses have no air-con and it would be so stuffy if they closed the windows all day.”
The gasworks that occupied the area was built in 1862 to manufacture gas using coal, and ceased operations in 1998.
Ms Iris Teo, 59, a resident of 40 years at Blk 468, said the site, when it was running, emitted faint gas smell once in a while, but the odour since last year was nothing she has experienced.
Noise pollution is also a perpetual issue as treatment works go on round-the-clock, said residents. A Kallang Riverside Condominium resident who wanted to be known as Mr CT Liu, 59, described the continuous noise as a dull hum and whirring.
The 3.14ha site is the first in Singapore to undergo soil remediation works, which is done to remove chemicals in the soil to improve its quality for future uses. Under soil thermal treatment, the ground is heated at high temperatures to treat contaminants.
The site will be spruced up as part of a future sustainable and car-lite waterfront precinct at Kampong Bugis.
The soil thermal treatment works are expected to be completed by the fourth quarter of 2022, followed by ground reinstatement and groundwater monitoring until the end of 2023.
SLA’s Assistant Chief Executive for land operations Thong Wai Lin said the authority takes feedback seriously, and understands residents’ health concerns.
“We maintain round-the-clock monitoring to ensure that the noise and odour readings continue to be within safety limits,” she said. Mitigating measures to minimise noise and odour are already in place, but we will continue to monitor the condition closely.”
An independent consultant engaged by SLA, AECOM Singapore, also carries out 24-hour site monitoring.
“Our assessment is that although intermittent odour has been reported in the duration of the project, the data does not indicate long-term adverse health effects to the community working and living in the vicinity,” it said.
Last Saturday (March 20), SLA met with eight residents and listened to their concerns, and explained the mitigating measures put in place.
Associate Professor Loo Chian Min from the department of respiratory and critical care medicine at Singapore General Hospital, who was also present at the two-hour meeting, assured residents that since exposure is transient and the level of pollutants is low, there is very low likelihood that adverse health risks will arise.
An SLA spokesman said: “This meeting with residents is not the last. SLA will continue to engage the residents over various channels.”
Jalan Besar GRC MP Denise Phua said she will continue to watch over the situation, and seek continued support from the relevant agencies.
“I can see that SLA had been tireless in putting up various measures to mitigate the smell, noise and air issues raised…SLA especially agrees with my position that there must not be any adverse health risks to the residents” she said.
The residents involved in the meeting on Saturday said they appreciated the authorities’ interventions, but it was not enough. They want the odour and emissions to be eliminated.
“You can’t have the readings at normal levels, and have people still falling sick,” said Mr Teo.
Retired banker Ms Teo, said: “If the emissions are within normal levels, why does my body react to it? I don’t want to have to close the windows and dry my laundry inside.”
Dr Chew Huck Chin, a respiratory physician from Respiratory Medical Associates, said local effects of pollutants that are not normally measured to determine air quality can cause irritative effects and cause sore throat, hives, teary and sore eyes as well as nasal congestion.
“The additional risks mainly pertain to those with pre-existing lung and heart problems, as they may experience an exacerbation of their condition. Prolonged exposure would add to their risk.”
Dr Chew advises residents to close their windows and doors as much as possible, turn on their air conditioning to reduce stuffiness, use indoor air purifiers, and to take their usual medications.
Dr Chew added that there is a risk of getting long-term health conditions from the odour and emissions, especially for vulnerable individuals including those with lung diseases, those with chronic obstructive pulmonary disease, infants and young children, and people who work outdoors.
The long-term effects can include allergic rhinitis, chronic eczema, bronchial asthma, and chronic eye irritation.