I've found something claiming to be the leaked report - I obviously can't vouch for its authenticity.
http://images.shoutwiki.com/acloserlookonsyria/2/2d/OPCW-UN_JIM_7th_Report.pdfWord of warning, it's horribly formatted. There are a few amusing segments, such as this long list of discrepancies surrounding the attack, that they nevertheless brush off without much thought. The excuse is, "meh, we didn't bother investigating". I particularly like how some alleged victims ended up in a hospital 125km away within 15 minutes of the attack occurring.
The Mechanism found that the reported symptoms of the victims were consistent with
exposure to sarin and that the available information on the medical impact of the
attack on 4 April 2017, including the health-care sector response, consistently
pointed to the use of sarin.
• Based on its review of open source material showing first responders in the hours
immediately after the incident, the Mechanism observed several methods and
procedures that appeared either unusual or inappropriate in the circumstances. In
particular, the Mechanism noted that fully equipped hazmat teams appeared at the
scene later that afternoon and reported early detection of the presence of sarin,
seemingly using a Dräger X-am 7000 ambient air monitor, which was not known
to be able to detect sarin. Of further concern to the Mechanism was the relative
unprofessionalism by which certain environmental samples appear to have been
taken, e.g. sampling from a muddy puddle.
• The Mechanism also noted scenes recorded just after the incident at the medical point to
the east of Khan Shaykhun, where rescue and decontamination activities filmed
shortly after 0700 hours showed rescue personnel hosing down patients with water
indiscriminately for extended periods of time. Such video footage also depicted a
number of patients not being attended to, and some para-medical interventions that
did not seem to make medical sense, such as performing heart compression on a
patient facing the ground.
• The Mechanism obtained expert analysis on the medical symptoms and response
indicated in witness statements and medical records, as well as treatment received
at a range of health care facilities, including those in a neighbouring country.
• Certain irregularities were observed in elements of information analysed. For example,
several hospitals appeared to start admitting casualties of the attack between 0640
and 0645 hours. The Mechanism received the medical records of 247 patients
from Khan Shaykhun who were admitted to various health-care facilities,
including those of survivors and a number of victims who died from exposure to a
chemical agent. The admission times of the records range between 0600 and
1600 hours. Analysis of the aforementioned medical records revealed that in
57 cases, patients were admitted in five hospitals before the incident in Khan
Shaykhun (at 0600, 0620 and 0640 hours). In 10 such cases, patients appear to
have been admitted to a hospital 125 km away from Khan Shaykhun at 0700
hours while another 42 patients appear to have been admitted to a hospital 30
km away at 0700 hours. The Mechanism did not investigate these
discrepancies and cannot determine whether they are linked to any possible
staging scenario, or to poor record-keeping in chaotic conditions.
• An inconsistency was identified in one of the Fact-Finding Mission biomedical results from
samples without a chain of custody. In sample number 133, the blood tested negative
for sarin or a sarin-like substance, while the urine sample tested positive for the sarin
degradation product isopropyl methylphosphonate. There is currently no explanation
regarding the inconsistency. Medical experts consulted by the Mechanism indicated
that the combination of the negative result in the blood and the positive result in the
urine was impossible. This inconsistency was considered to be most probably the
result of cross-contamination in the sampling process.
• The Mechanism observed from open sources that treatment of victims from Khan Shaykhun
frequently involved oxygen and cortisone therapy. This treatment is not
recommended for sarin intoxication, but is mainly for lung damage, as would be
caused by either chlorine or vacuum bombs.
• Based on consultations with two medical experts, the Mechanism found that the response
by rescue workers and medical personnel in Khan Shaykhun on 4 April 2017 had
been essentially consistent with the use of sarin on such a scale. While some
potentially important irregularities were identified throughout the rescue operation
and in medical records, they may be explained by factors such as poor training or the
chaotic conditions, or by attempts to inflate the gravity of the situation for depiction
in the media.
Elsewhere in the report, they note that the aircraft the US claimed was "over Khan Shaykhun" was in fact about three miles away when the incident occurred:
On 7 April 2017, United States authorities publicly released a statement and a map
depicting a flight path of an aircraft originating from Al-Shayrat airbase that “was
over Khan Shaykhun” at approximately 0637 and 0646 hours. The Mechanism
had access to a further aerial map depicting the path of an aircraft alleged to have
been in the airspace around Khan Shaykhun between approximately 0644 and
0651 hours on 4 April 2017. The flight is depicted as conducting a circular loop in
the vicinity of Kafr Zita and the north-east of Khan Shaykhun. The map indicated
that the closest point that the aircraft was to Khan Shaykhun was approximately 5
km away. Additional information provided to the Mechanism referred to two
aircraft having taken off from Al-Shayrat airbase at around the same time as
indicated above, ten minutes apart, following the same flight path. Based on the
above, the Mechanism found that air activity had taken place around Khan
Shaykhun at about the time of the sarin incident.
They interviewed the pilot, and found that what he was telling them was consistent with the flight logs, but essentially brush it off because it doesn't fit the conclusion. They suddenly learn to be sceptical of what someone is telling them - but then throw this out the window whenever they interview unnamed "witnesses".
The Mechanism interviewed the pilot associated with one of the entries in the log book,
who used the call sign “Quds 1” and flew a Su-22 at the relevant time that day. The
pilot stated that no chemical weapons had been used, and that the mission that
morning had been to the west of Kafr Zita using three 500kg conventional munitions.
This was found to be consistent with the details contained in the log book. According
to the pilot, the closest distance to Khan Shaykhun on this date was approximately 7
to 9 km, while executing an attack against targets west of Kafr Zita. While the
Mechanism was able to confirm severe structural damage to a building in the general
vicinity of one of those targets via analysis of satellite imagery, it could not precisely
determine when this damage occurred.
"Perhaps you want me to die of unrelieved boredom while you keep talking." - Martin Luther