The Kuala Lumpur airport terminal, where Kim Jong-nam was killed with VX nerve agent, has been declared free of any “hazardous material” by Malaysian police.
Security teams in protective suits had earlier swept the area.
According to Malaysia’s health minister, an autopsy suggested VX used to kill Kim Jong-nam caused “very serious paralysis”.
An Indonesian woman arrested for the murder has said she was given 400 Malaysian ringgit ($90) to carry out a prank.
Siti Aisyah, 25, told Indonesian embassy officials that she was given the cash to smear Kim Jong-nam’s face with “baby oil” as part of a reality show joke.
VX is classified as a weapon of mass destruction by the UN. A drop on the skin can kill in minutes.
Kim Jong-nam died on February 13 after two women accosted him briefly in a check-in hall at Kuala Lumpur International Airport’s low-cost carrier terminal, known as KLIA2.
Health Minister S Subramaniam said the discovery that the VX toxin was used confirmed the hospital’s autopsy result, which suggested that a “chemical agent caused very serious paralysis”, leading to death “in a very short period of time”.
Kuala Lumpur airport has been swept for toxic chemicals by various specialized police teams, forensic experts, the fire department’s hazardous materials unit and the Atomic Energy Licensing Board.
“As a result of this screening process done we confirm: number one, there is no hazardous material found in KLIA2. Number two, KLIA2 is free from any form of contamination of hazardous material. And thirdly, is KLIA2 is declared a safe zone,” said Abdul Samah Mat, the police official heading the investigation.
There is widespread suspicion that North Korea was behind the attack, which it strongly denies.
A Vietnamese woman and a North Korean man have also been arrested in connection with the killing.
The Vietnamese foreign ministry confirmed that the Vietnamese national being held was 28-year-old Doan Thi Huong, saying she had told officials she thought she was taking part in a television prank.
At least seven other suspects are wanted for questioning by police, including Hyon Kwang Song, 44, second secretary at the North Korean embassy in Kuala Lumpur.
The officials said they did not see any physical signs that the suspect had been affected by the chemical.
Malaysian police say the attackers had been trained to immediately wash their hands after the attack.
Some experts have suggested that they might have each smeared two different non-lethal elements of VX, which became deadly when mixed on Kim Jong-nam’s face.