As Tishah B'Av approaches, Rav Ofir Malka addressed a halachic question about electronic cigarette use during the fast, ruling that vaping is prohibited because of the flavored liquid in the devices.
On his Halachah Lemaaseh radio program, Rav Malka was asked whether smoking an electronic cigarette is permitted on Tishah B'Av. "Electronic cigarettes may not be smoked on fast days, and certainly not on Tishah B'Av," He said.
Rav Malka noted that even limited leniency some authorities grant to conventional cigarettes applies only "privately after chatzos."
He attributed the prohibition to the flavored liquid in electronic cigarettes. "It has moisture, and that is considered like taste, similar to sucking on something," He said.
When a caller contended the liquid is not fit for consumption, Rav Malka responded that in diluted form it has a pleasant taste. "It is moisture that is enjoyable to you. In low concentrations, it tastes good to you," He explained, concluding that vaping is therefore forbidden during a fast.
Rav Malka also stated that because the liquid has flavor, it requires kosher certification year-round, not only during Pesach. "It has an enjoyable taste in every respect, together with that moisture," He said.
The rabbi was also asked about someone who accidentally ate during a fast. "He certainly must stop immediately and continue fasting," Rav Malka said, explaining that inadvertent eating does not exempt a person from completing the remainder of the fast.