Days after OC Transpo said that passengers were free to vape on board and on transit property, the City of Ottawa has reversed its position.

City solicitor Rick O’Connor was asked to "undertake a more fulsome review" of OC Transpo's e-cigarette policy, and found that vaping passengers could be fined up to $5,000, he wrote in a memo that was distributed to CBC News Thursday evening.

"It is important to clarify that the use of e-cigarettes is not permitted on OC Transpo property, including buses. This restriction applies to bus operators as well as members of the public," he wrote.

In an email dated March 6, assistant general manager of transit operations Troy Charter told CBC News that passengers could not be fined for using e-cigarettes because they were not regulated as a tobacco product by Health Canada.

If passed, the Ontario government's proposed legislation to ban the use of e-cigarettes wherever smoking is prohibited would not take effect until Jan. 1, 2017. Age-based sales restrictions would take effect one year earlier, on Jan. 1, 2016.

Until legislation was passed, which would allow OC Transpo to amend its bylaws, Charter asked that passengers avoid using e-cigarettes "in the spirit of the 'No Smoking' policy."

After CBC News published OC Tranpo's e-cigarette policy on Wednesday, O'Connor said he was asked to review the policy.

But O'Connor now said that the use of e-cigarettes contravene a bylaw that prohibits anyone from interfering “with the comfort or convenience of any other person." Since OC Transpo received 26 complaints related to e-cigarettes in 2014, "it is apparent that the use of e-cigarettes may interfere with the comfort and convenience of other transit riders" and could be subject to "enforcement action," O'Connor said.

"I would like to apologize for any confusion that the earlier legal comments may have given rise to. OC Transpo staff were following legal advice being provided and we are now providing this updated advice to them," O'Connor said.