In her former role as a Port Control Officer in Laem Chabang, Thailand, she and her team had uncovered what seemed to be a large shipment of heroin, divided into hundreds of large ‘bricks’, inside a container.
Brick by brick, she and her colleagues weighed and inspected the drugs after an initial test confirmed the presence of heroin. All of this information – which would be crucial for any future investigation or prosecution – then had to be carefully logged and analyzed to improve the port’s risk management.
“This is the boring, hard work of port officials that no one ever hears about,” says Sirima.
Tedious though it may be, port and customs workers like Sirima are on the front lines of efforts to prevent drugs, weapons, waste and other illicit materials from either entering or leaving countries. Their work to detect, identify and analyze suspicious shipments helps keep the harm from all kinds of criminal actors – from individuals to transnational organized crime groups – in check.
Sirima, now the Chief of the Customs Service Unit in the Chiangdao Customs House, says that Thailand plays a particular role in efforts to stop trafficking of illicit goods. “We’re a logistical hub in Southeast Asia,” she explains. In the case of synthetic drug trafficking, for example, “this means that criminal actors are importing precursor chemicals into Thailand or our neighboring countries. Then, they manufacture the drugs and try to distribute them to the rest of the world.”
Thailand – together with Laos and Myanmar – also forms part of the Golden Triangle, a tri-border area known for its production and distribution of drugs like opium, ketamine and methamphetamine. “Some areas of the Golden Triangle are controlled by armed groups, making it hard to police,” she adds.
As noted by the 2024 World Drug Report, these drug traffickers also engage in other crimes like wildlife trafficking, financial fraud and illegal resource extraction, with communities and the environment suffering the consequences.
In addition to trafficked drugs, Sirima says she and her team often come across illegal waste shipments, primarily from Europe, North America and Asia. “Sometimes, the shipments are labelled as being cardboard or other kinds of paper – things that can be recycled in Thailand. Then, you open up the container, and it could be for example old computers, e-waste, or plastic and municipal waste, which is not so easy to recycle.”
Such waste is illegal under Thailand’s national legislation and violates the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and their Disposal.
Much of trafficked waste around the world ends up in illegal landfills or the ocean, or it is burnt in the open – endangering human health, ecosystems, and livelihoods.
Sirima also serves as a member of the local profiling committee at the Port Control Unit (PCU), where she analyses data and manages risk to increase the PCU’s detection of smuggled or illicit goods.
“There are more than 10,000 shipments coming into the port every day,” Sirima says. “We can only inspect a percentage of these, meaning we have to be careful and accurate in our assessments and analyses.”
This means, Sirima notes, knowing both Thai and global regulations on the environment, drugs, intellectual property, dual-use chemicals (which can be used for legitimate commercial applications but also to produce weapons or drugs) and more. They then must apply this knowledge during shifts that can last up to 12 hours on alternating days and nights.
But this deep knowledge and careful assessments can really pay off – like when Sirima helped to identify a 130-tonne illegal waste seizure in 2022.
For the past two decades, UNODC has supported Member States to establish, train and equip PCUs and works with port control officers like Sirima to enhance their ability to disrupt the illicit flows of containers, cargo and mail. Sirima herself has received UNODC training on how to target, detect and inspect suspicious shipments.
“It’s been very useful,” she enthuses. Of particular importance to her was the UNODC’s donation of drug and precursor identification kits, which allow officers to rapidly identify the most commonly encountered drugs and prescursors in illicit traffic.
After receiving training on the kits, Sirima began to use them in her normal duties, noting they’ve helped lead to important seizures. “We used the drug kit to test a suspicious substance on its way to Syria from Thailand. The test was positive, we alerted Thailand’s Office of the Narcotics Control Board and managed to seize hundreds of kilograms of heroin.”
Cases like these, Sirima says, ultimately make all of the pressure and long hours worth it. “I’m proud of myself – even if nobody else knows.”
To learn more about the Passenger and Cargo Control Programme (PCCP), implemented in cooperation with INTERPOL and the World Customs Organization (WCO), click here.

