Good friar,
A bishop can only make what rules don’t contradict the extant rules. When the rules as written give the competence to the episcopal conference, it’s delegation of higher authority to the whole of the conference.
In this case, the GIRM is pretty clear - the bishop isn’t the competent authority - the Holy See has delegated to the individual conference permission to
exempt from the requirement for wax, and/or for oil.
Rome says that it’s wax for candles, and wax or oil for the altar lamp. Rome delegates (in the older GIRM) permission to allow other substances to the conferences. The delegation is not to the individual bishops.
And the USCCB has never authorized anything else. It’s no prohibition. It’s a lack of enabling, when the enabler is actually Rome via the
mechanism of the conference.
Nothing else is authorized, and competency to authorize exemptions is specified by Rome in the legislation (the GIRM) itself.
In the current GIRM, No. 216:
316. In accordance with traditional custom, near the tabernacle a special lamp, fueled by oil or wax, should shine permanently to indicate the presence of Christ and honor it.[129]
And it’s worth noting that 216 isn’t one of the areas allowed to the bishop’s conference for adaptation:
[390. It is for the Conferences of Bishops to formulate the adaptations indicated in this General Instruction and in the Order of Mass and, once their decisions have been accorded the recognitio of the Apostolic See, to introduce them into the Missal itself. They are such as these:
• the gestures and bodily posture of the faithful (cf. no. 43);
• the gestures of veneration toward the altar and the Book of the Gospels (cf. no. 273);
• the texts of the chants at the Entrance, at the Presentation of the Gifts, and at Communion (cf. nos. 48, 74, 87);
• the readings from Sacred Scripture to be used in special circumstances (cf. no. 362);
• the form of the gesture of peace (cf. no. 82);
• the manner of receiving Holy Communion (cf. nos. 160, 283);
• the materials for the altar and sacred furnishings, especially the sacred vessels, and also the materials, form, and color of the liturgical vestments (cf. nos. 301, 326, 329, 339, 342-346).
It shall be permissible for Directories or pastoral Instructions that the Conferences of Bishops judge useful to be included, with the prior recognitio of the Apostolic See, in the Roman Missal at an appropriate place.](
http://www.usccb.org/prayer-and-wor...uction-of-the-roman-missal/girm-chapter-9.cfm)
It is also worth noting that the current code doesn’t specify wax candles other than for the tabernacle lamp… just candles. (GIRM 117).
- The altar is to be covered with at least one white cloth. In addition, on or next to the altar are to be placed candlesticks with lighted candles: at least two in any celebration, or even four or six, especially for a Sunday Mass or a Holyday of Obligation, or if the Diocesan Bishop celebrates, then seven candlesticks with lighted candles. Likewise, on the altar or close to it, there is to be a cross adorned with a figure of Christ crucified. The candles and the cross with the figure of Christ crucified may also be carried in the procession at the Entrance. On the altar itself may be placed a Book of the Gospels distinct from the book of other readings, unless it is carried in the Entrance Procession.