That 837psi sounds very reasonable.
http://en.wikipedia.org/wiki/Carbon_dioxide
"Candy called Pop Rocks is pressurized with carbon dioxide gas at about 600 PSI."
"Liquid carbon dioxide was used as a refrigerant prior to the discovery of R-12 and may be enjoying something of a renaissance [2] due to environmental concerns. Its physical properties are not favorable, having a low critical temperature of 88F/31C (the maximum temperature at which it will condense from gas to liquid) and high critical pressure of 1070 psi (the pressure required for phase change at the critical temperature). These properties necessitate the use of very strong refrigeration plumbing to contain the operating pressure of ~1400 psi, in contrast to pressures of ~300 psi for R-134a systems."
I love how some people are always so opinionated about things that they don't have all the facts and info on.