I'll try to answer those three questions very quickly.
In a typical high-volume slick-water hydraulic fracturing operation in a shale gas formation, there are roughly five types of chemicals that are necessary. I won't give you their chemical names—one can look those up—but one needs to add a lubricant to the water so that pumping the high volume used under very high pressure over a very long distance can be done with a reasonable amount of horsepower at the surface. That lubricant is typically a hydrocarbon derivative. There is a biocide necessary to kill the bacteria that otherwise would grow in the well and clog the well. There is an anticorrosive to prevent rusting of the all-important steel casing—that's the first line of defence for the entire life of a well that's expected to last 20 to 50 years. There's an antifouling agent to stop scaling—that is, deposits of hard minerals on the inside of the casing in the well that would otherwise clog it. And there is an acid that is used to clean out perforations right before the hydraulic fracturing process and immediately after the start of it.
Those are the general categories of chemicals. Some of them are relatively benign, even though you would not want to be drinking them or having them in your trout streams. Others are known to be toxic, carcinogenic, and don't belong in the human environment. But I should also emphasize that once the fluid comes back—and I'm trying to answer your second question now—it contains not only the chemicals that were put in on the way down but the material that was picked up from the shale. As I mentioned before, notably, in black shales, shales containing gas, the most dangerous of those are the heavy metals--strontium, barium, uranium, and radium--some of which are also naturally occurring radioactive materials.
The industry is fond of saying that most of what they pump down stays down. What they fail to talk about is the timeframe in which they're counting. Typically, the returned fluid, after the fracturing process, is counted as returned fracturing fluid only during about the first week or two of flowback operations. However, all shale gas wells continue to produce fracturing fluid and brine containing heavy metals for the entire life of the well. One has to be very careful. One cannot say that on average, 50% of the fluid comes back. One has to say under what timeframe one is making that measurement. Typically almost all of the fracturing fluid comes back during the life of the well.
In answer to the third question, whether I take comfort from my friends in New Brunswick saying they're trying to keep up with regulations, I don't know. I don't know what their starting point was for their regulations. I don't know what the current, perhaps modified, set of regulations looks like. I would only suggest that they go to perhaps the closest match to New Brunswick, which I would say is Pennsylvania, and take a look at the substantially revised regulations that have been put in place just in the last year as a result of only three years of substantial development.