Actually, a cup of coffee might spill, a glass of milk; eruption is a better term for a DilBit pipeline or pump-station "event".
Keystone was predicted to spill no more than once every seven years....
After being in operation less than one year, Keystone tallied its eleventh spill--at a pump station, which TransCanada insists "don't count".
It was in Ludden, North Dakota, May 7, 2011. A 3/4-inch pipe fitting failed under the pressure, erupting DilBit sixty feet high--21,000 gallons in minutes.
Since pipeline operators are not required to say what they are piping, emergency responders didn't discover until ten days later that what turned the Kalamazoo River black was DilBit. Original expectations were that cleanup would take a few months. But after two years the job was not over... and apparently never will be. The EPA has declared thirty miles of the Kalamazoo River "... essentially permanently polluted".
Typically, 90% of crude oil spilled into water can be captured with booms and skimmers.
DilBit is from 50% to 70% bitumen, diluted with natural-gas condensates collectively called diluents (exact composition of diluents is a "trade secret"). DilBit in the Kalamazoo River was 70% bitumen. After diluents separated out, bitumen sank and coated the riverbed.
Coincidentally, nine days before DilBit tarred the Kalamazoo River, the EPA warned that the "proprietary nature" of DilBit diluents could complicate clean-up.
Over the last ten years, average clean-up cost of spilled crude oil has been about $2,000 per barrel; DilBit in the Kalamazoo has cost $29,000 per barrel, making it by far the most expensive spill in U.S. history--over $800 million so far. Much of the bitumen cannot be cleaned up without destroying the riverbed.
DilBit pipelines operate at elevated temperature and high pressure to reduce viscosity and increase piping efficiency--increasing the risk of corrosion for a product that, compared to crude oil, contains huge amounts of abrasive quartz particles. DilBit's extreme acidity and sulfur content also weaken steel.
TransCanada responded to the corrosion problem by seeking a safety waiver to use thinner-than-normal steel for Keystone XL.
What little research done regarding DilBit has been conducted by industry, so it's proprietary. That's right, the old "trade-secrets" suppression of information helping to keep government regulating DilBit as crude oil.