Oh dear. It’s the possible result that 23% of Astroengine readers (who voted that they wanted Phoenix to find “A strong indicator for the presence of organic compounds” as of August 5th, 3am) did not want to see. According to Phoenix mission control, recent analysis by the MECA instrument on board the lander appears to have discovered something bad hiding in the Martian soil. Perchlorate, a highly oxidizing substance appears to have been detected just under the icy top-layer of the surface, possibly hindering the development of life (certainly the possibility of current life, perhaps past life too). Over the weekend the Internet exploded with reports that we were on the verge of a major discovery, leading to some reports indicating Phoenix had discovered life on the planet (nah, couldn’t happen). However, there were more grounded theories that further evidence for organic compounds may have been found or there was something more compelling than the discovery of water. But no, it looks like the forthcoming press conference (Tuesday, 11am) might have some bad news for us. A chemical that would actually halt the development of life may have been unearthed, possibly hindering the future of manned exploration of the Red Planet…
This is a strange development to say the least. After so many exciting discoveries by the Phoenix scientists, we may be in for a contradictory announcement in the morning. Could this be the announcement we’ve all been waiting for? You know, the one that will be even bigger than the previous ones? This is the problem with sketchy reports from unnamed sources, they give just enough to get you excited but rarely divulge the details. So it looks like Aviation Week may have gotten it right in the end; we are indeed in for an earth-shattering discovery: There’s no life, there never was, and the future ain’t great for manned exploration (if the “search for life” is out of the equation).
So this new press release indicates the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) has found an oxidizing compound that may make the conditions in the Martian arctic adverse for life as we know it to survive. In fact, perchlorate-based chemicals are toxic to human health and often found as a by-product to industrial manufacturing.
Perchlorate is both a naturally occurring and manmade contaminant increasingly found in groundwater, surface water and soil. Most perchlorate manufactured in the U.S. is used as an ingredient in solid fuel for rockets and missiles. In addition, perchlorate-based chemicals are also used in the construction of highway safety flares, fireworks, pyrotechnics, explosives, common batteries, and automobile restraint systems. Perchlorate contamination has been reported in at least 20 states. Perchlorate greatly impacts human health by interfering with iodide uptake into the thyroid gland. In adults, the thyroid gland helps regulate the metabolism by releasing hormones, while in children, the thyroid helps in proper development. Perchlorate is becoming a serious threat to human health and water resources. – From the California Toxic Substances Control website.
There is however, some confusion as to why this chemical has not been detected before now and scientists have been awaiting results from the Thermal and Evolved-Gas Analyzer (TEGA) to confirm the MECA findings. It could be that this chemical was somehow transported on board the Phoenix lander, or it seems possible it might have been produced by a reaction between the lander’s rockets and Mars soil. However, due to the previous lack of perchlorate detection, terrestrial contamination seems unlikely.
“When surprising results are found, we want to review and assure our extensive pre-launch contamination control processes covered this potential,” – Barry Goldstein, Phoenix project manager, NASA’s Jet Propulsion Laboratory.
So before we get too concerned, we’ll have to wait for the press conference at 11am… Hang in there Phoenix, your job is far from over…
Source: Phoenix
astroengine.com 
So there is, instead, a planet covered with potential rocket fuel. Oh, dear, what a problem. Would you care to give me an exclusive marketing contract to sell it, if it is such a bad thing?
Perchlorate can be found naturally occurring on Earth. The Chilean Atacama desert is full of it and incidentally the soil from there was brought to the US as a fertilizer, though the contamination was not known at the time. If the probe landed on Earth and found it, thinking the finding was significant would be way premature as obviously there is life here.