The "not to bring list" for the August festival is being reviewed by Green Man organizers.
This comes after Glastonbury Festival, which takes place later in June, requested that attendees refrain from bringing disposable vapes this year.
On Green Man's list, there are already such things as fireworks, explosives, pets, and glass bottles.
The festival's organizers promised to announce whether or not disposable vapes will be included in August.
This week, Glastonbury added disposable vapes to its list of "what not to bring.".
Disposable vapes "pollute the environment and can be hazardous at waste centers," according to a revised message on the company's website.
The website for Green Man already states a list of "forbidden items," but it does not currently mention disposable vapes.
However, the list does advise festival goers to bring "a sense of humor, a smile, exquisite music taste, and a friendly attitude" along.
The 2017 edition of Green Man will take place from August 17 to 20 and feature performances by First Aid Kit, Devo, and Spiritualized as its headliners.
In the Black Mountains, close to Crickhowell, Powys, it will take place.
