The candles for liturgy are 51 percent beeswax. The vigil lights, however, are made not of wax but of paraffin. Since this is an oil-based product, when the price of oil goes up, so does the price of the candles. Think of the concentration of candles as a boiler and the shrine alcove as a chimney without a vent. I leave it to the medical profession to inform us about its possible carcinogenic effects.
Carriers are reluctant to insure churches that leave live flames burning unsupervised.
It is ironic to note that this contemporary structure was built to replace the previous church that burned down. The value of a vigil light is not in the candle but in the prayerful intention of the one who lights it. It is the lighted pledge of your prayer. Ninety percent of the churches have converted to electric candles without any great loss of devotion. Keep in mind that the discussion is not about candles in the official liturgy but about vigil lights for private devotion.