Let's hope this spilled fuel didn't hit groundwater. 

Good point, Joshua, and you highlight the fact that all parts and all aspects of that environment are critically sensitive.  Yes, both the aquatic and the riparian environments associated with the nearby Yellowstone River are incredibly sensitive, especially given that cutthroat trout from the lake that are still under threat from nonnative and illegally introduced lake trout are still in the river for the tail end of their spawning season.  But, groundwater resources, including groundwater feeding extremely sensitive and explosively heated thermal features, are highly sensitive and potentially subject to both as yet unknown impacts and as yet unknown responses to having gasoline injected into their systems.  There are going to be significant impacts, clearly including scenic impacts, on roadside grasses, brush, trees, and other vegetation.  There are also the probable human and wildlife health and human national park experience impacts of having this much gasoline dumped in such a heavily used and sensitive national treasure.

So, some might want to characterize thes issues as just water, actually gasoline, under the bridge or, in this case, eventually under the bridges, plural, then over the falls.  But, I have what I believe is a pertinent policy question.  Given the sensitivity of all parts and all aspects of that environment, given the tricky driving conditions often caused by the weather up there, and given the often extremely heavy and dangerously distracted traffic on those roads; why did the NPS think there was a rational need to allow tandem trailer rigs of any type, much less tandem trailer rigs hauling flammable hazardous liquids, in the park at all?  Any of us who ahve been responsible for highway transport of anything, much less hazardous cargo, know that introducing that tandem connection introduces additional risk, especially of sway and skid control problems, especially on wet pavement, and especially along that narrow twisting and turning stretch of road along the river.  It might be different on a good stretch of interstate; but, given the general expense of operating in the sensitive and difficult environment of the park under even the best of circumstances, the added expense of using two single rigs rather than a tandem would clearly have been both insignificant and justified.  What incompetent dirty rat bastard made the decision to allow the use of that tandem rig, anywhere in the park, but especially hauling gasoline along the river in the rain?

Agreed, Humphrey, the "pup" trailer behind a straight tanker truck (which I think was involved in this accident) or even more challenging a semi-tanker with the short "pup" trailer behind it, is a tricky rig to herd in trying conditions, not limited to a legal minimum, twisty two-lane road.

The wisdom of using any, but the safest fuel-hauling rigs in the Park warrants careful consideration by NPS officials, as does the use of large highway trucks to supply the various concessions in the Park.

The silliest thing in the world is to see a maximum-length semi pull in front of the Tower store in the middle of the afternoon to unload supplies that would fit into the bed of a 6 foot pick-up truck with room to spare -- tangling traffic for most of an hour and precipitating amusing stand-offs between the truck drivers and those of maximum sized tour buses.

But I digress.

The greater evil is the NPS policy requiring gasohol to be sold in the Parks even though ample scientific evidence shows that the alcohol (more of a political additive, than anything else) is ineffective at higher altitude and low temperatures -- particularly unnecessary in modern, fuel injected vehicles.  Today's cars and trucks are all fully capable of running as cleanly on E10, a blend of 10-percent ethanol and 90-percent gasoline or gasoline without added oxygenating additives.  Sophisticated computer systems and sensors constantly monitor the engine and the exhaust to be sure that everything (i.e., the air-fuel mixture) is kept at its optimum level with both fuels, but drivers will get better mileage with fuel that doesn't contain alcohol.

Leaving aside detailed discussion of the horrible things that the alcohol gradually does to the fuel systems of even vehicles of recent production -- ultimately eroding engine performance to unacceptable emission levels -- the alcohol significantly changes the migration of spilled fuel in the ground, since the alcohol is miscible in water, while the petroleum component of the fuel isn't.

A bit of background:

In the early 1990s, the United States government issued a series of amendments to the Clean Air Act that included the requirement to use oxygenated gasoline (minimum oxygen content of 2.0-percent by weight for reformulated gasoline in ozone non-attainment areas, such as LA, not Yellowstone) to help the fuel burn more completely in combustion. One of the favored oxygenates was methyl tert-butyl ether, or MTBE, although the environmental impact and toxicity had not been evaluated.  Why?  It was cheap and it was assumed that MTBE would be entirely "consumed" in the engine (which proved to be a really stupid assumption).

This chemical compound was chosen due to its low price and because it helped mixers generate higher octane ratings. All seemed well until California discovered in 1995 that MTBE was showing up in high concentrations in its drinking water, which was traced back to spilled gasoline and leaky underground containers, as well as the use of MTBE "enhanced" gasoline in motorboats on lakes and reservoirs. 

Ethanol was widely seen as a safer replacement for MTBE and its use was pushed by the agricultural industry, although moisture-saturated ethanol is no better burned than was MTBE and an interesting variety of denaturing and detergent additives are used in the ethanol added to the gasoline to keep the alcohol in the petroleum suspension.

Is a 10-percent ethanol blend unleaded gasoline eco-friendly?  Obviously, the burning of fossil fuels isn't a great thing in and of itself for the environment, so the question may be whether burning ethanol-infused fuel is better or worse than gasoline.

Whether eco-friendly as a fuel or not, the spilling of Ethanol blend unleaded gasoline isn't eco-friendly.  In fact, it is difficult to trace the migration fronts of the two major components of gasohol -- presumably the cause of the delay in monitoring and/or cleaning-up the spilled fuel between Bridge and Mud Volcano.

The experience in California showed that the MTBE moved through the moisture in the ground about three times faster than did the petroleum component of the fuel.  Last studies that I read, indicate that Ethanol is only about twice as fast in migrating through ground moisture.

Both additives are quick to be carried in ground water and move with the ground water -- arriving about twice as fast at any distance from the point of introduction as the contaminated water itself.

The accident on the 27th raised two distinct issues for NPS to address:

Mandating use of the safest methodology to transport motor fuel in the park.

     2.  Mandating sale and use of the safest fuel in the park to minimize the impact of spills and accidents.

Yeah, Anonymous, you're right about the tandem trailers in the park, especially on that road and in the rain.  And, I saw what you did there with the rest of your stuff.