Ho Chi Minh City police have dismantled an illegal operation producing and distributing arsenic trioxide (white arsenic), a highly toxic substance, for use in dental products. Shockingly, the poison was manufactured by hand in a residential bedroom before being sold to dental equipment suppliers.

doc chat nha khoa 6.png
Three suspects arrested (from left to right): Vo Thi Thu Oanh, Tang Thi My Hoa, Tang Hoang Vinh. Photo: Police

On January 28, the city’s Economic Police Department confirmed that it had filed charges and detained three suspects: Vo Thi Thu Oanh (born 1976, resident of Ban Co ward), Tang Thi My Hoa (born 1978, of Tan Binh ward), and Tang Hoang Vinh (born 1983, of An Dong ward), for illegally producing and trading toxic substances.

The investigation began in mid-December 2025 when police raided Tan Da Dental Equipment Shop, located in the Ngo Quyen apartment complex, An Dong ward.

doc chat nha khoa 1.png

Police inspect the dental equipment store. Photo: Police

doc chat nha khoa 4.png
Toxic dental products seized during the operation. Photo: Police

There, authorities discovered a large quantity of unlicensed products labeled ArsenicBlue 5g and Pâte Nécronerve  -  commonly used in dental procedures to kill nerve tissue.

The shop owner was unable to provide any invoices or documents proving the legal origin of the goods.

Forensic testing by the Institute of Criminal Science confirmed that the samples contained As₂O₃ (arsenic trioxide)  -  a carcinogenic and potentially lethal poison under special regulatory control. The total seized quantity exceeded 674 grams.

Toxins made in bedroom lab

doc chat nha khoa 2.png
doc chat nha khoa 3.png
Various arsenic-based products seized as evidence. Photos: Police

Further investigation revealed that Vo Thi Thu Oanh had turned her own bedroom into the main production site.

She personally sourced the chemicals and manually prepared the products by mixing, processing, and bottling them without any safety equipment or protective measures. This not only violated health regulations but also posed a risk of environmental contamination and toxic exposure.

Once produced, the items were supplied to Tang Thi My Hoa, who managed the dental supply store, with assistance from Tang Hoang Vinh. Together, they distributed the illicit nerve-killing pastes to dental suppliers.

From 2024 until their arrest, Hoa sold more than 3,000 boxes to clinics across Vietnam, raking in over 1.25 billion VND (approx. $50,000), with hundreds of millions in illegal profit.

Police are now investigating the list of dental clinics that purchased and possibly used the unregulated products, in order to issue warnings and take necessary enforcement action.

According to HCMC police, arsenic is a dangerous substance. Improper use or unapproved formulations in dental care can pose severe threats to patient health.

Dam De