SINGAPORE, Aug. 20 -- As vaping gains ground despite being illegal, companies here are grappling with how to enforce workplace bans.

Some have opted for zero tolerance while others rely on warnings or internal whistleblowing, CNA reported today, adding that enforcement remains uneven.

International education group EtonHouse is among those that have codified their stance, spelling out disciplinary action including termination in its employee handbook.

"Vaping is illegal in Singapore, and EtonHouse takes compliance with local laws seriously," a spokesman told the Singapore-based news agency.

Other firms such as Busy Bees, Red Crowns Senior Living and several food and beverage outlets said vaping is banned on their premises, with staff r...