Fraud Exposed in NIST WTC 7 Reports

Chris SarnsEditor’s note: To this day most people, including many architects and engineers, are not aware that a third skyscraper, World Trade Center Building 7, mysteriously collapsed along with the World Trade Center Twin Towers on September 11, 2001. The official report on this building’s collapse by the National Institute of Standards and Technology (NIST) has been challenged by many reputable and credentialed technical professionals. The NIST analysis has not undergone the rigors of scientific peer review – the typical pathway for validating significant scientific theories. Chris Sarns’ research appears in Dr. David Ray Griffin’s book titled " ." The studies below represent years of work by Chris in unraveling some of the most glaring inconsistencies and outright frauds in the NIST report on World Trade Center 7. He demonstrates that the NIST’s theory of the fire-induced collapse of Building 7 is faulty and misleading.

The destruction of this skyscraper on September 11 was truly unprecedented in the history of high-rise buildings. More than 1,700 architects and engineers at are demanding a new investigation. Chris has also been deeply involved in the work of , where he provides his expertise on WTC7.

Chris disproved NIST’s claims in five centrally important areas:

BURNED-OUT FIRE – The timing of the fire on floor 12 exposes NIST's false claim that fire led to the collapse. MAGICAL THERMAL EXPANSION – NIST used numerous unscientific methods and fraudulent inputs to get the key girder to fail in its computer simulation. FICTITIOUS DEBRIS DAMAGE – The fictitious “10-story gouge” claimed early on by NIST in WTC 7’s south face is exposed. NON-EXISTENT DIESEL FUEL FIRE – NIST’s fraudulent diesel fuel fire hypothesis is exposed. MISSING SHEAR STUDS – NIST’s claim in its Final Report about the lack of shear studs on the floor support girder between columns 44 and 79 is exposed.

Quotes from the NIST WTC7 report are shown in "brown"

The timing of the fire on floor 12 exposes NIST's false claim that fire led to the collapse.

The images shown below on the left are Sarn's approximations using the photogrpahs as a guide of where and at what times the fire existed on floor 12.

On the right is the NIST ANSYS computer model for the same times.

"Note that only window glass breaking times were prescribed in the fire model. The observed fire activity gleaned from the photographs and video were not a model input" NCSTAR 1-9 Vol.2 p. 378 [pdf p. 40]

NIST will not release the input data because doing so might " "

Quotes and photographs from the NIST reports on the collapse of WTC 7

Fire spread:

"On those floors that were mostly subdivided into offices (such as Floors 11 and 12), the fire would have grown within a single office, reaching flashover within several minutes. After about 5 to 15 min, the ceiling tile system would have failed from the heat, and the hot air would have flowed over the office wall. Soon the hot air would fail the ceiling of an adjacent office, and eventually the thermal radiation would ignite the contents in this office. Fire spread would have been similar for offices separated by a corridor, although this would have taken longer, since the hot air would have to travel further and would be cooling along the way." NCSTAR 1A p. 19 [pdf p. 61]

"The mass of the furnishings per office was not known" NCSTAR 1-9 Vol.1 p. 60 [pdf p.104]

"the average combustible fuel load on the 11th and 12th floors was estimated as 32 kg/m2" NCSTAR 1-9 Vol.2 p. 376 [pdf p.38]

All things being equal, the fire would have spread consistently. But the NIST ANSYS computer model (above) inexplicably bypassed the offices to the southwest of column 79, burns around column 79 on the east side and then burned the offices to the southwest of column 79 two hours later.

"Fires on Floors 11 to 13 persisted in any given location for approximately 20 min to 30 min." NCSTAR 1A p. 47 [pdf p. 89]

Photos showing progression of fire:

"From 11:30 a.m. to 2:30 p.m. Looking from southeast corner to the south face.

Fire on floor 12;[1] area above covered with smoke

Fire on floors 11-12[1] moved to east face and progressed to the north

[1] fires reported on floor 14, but photographs showed east face fires on floor 12." Part IIC p. 21

Figure 5-114. Oblique view of the east face of WTC 7, taken at 2:08:28 p.m. +/- 1s Fire was first seen on the 12th floor at 2:08 p.m. toward the south end of the east face. Further south on this face, the window glass was still intact, indicating that this fire had burned in the building interior as it turned the southeast corner." NCSTAR 1-9 Vol.1 p. 245 [pdf p. 289]

Figure 5-117. Photograph showing fires on the east face at 2:28:43 p.m. +/- 1s [34, 37 and 40 are column numbers] "By around 2:30 p.m., the visible flames had diminished, but the fire had spread both south into the southeast corner and north, reaching two-thirds of the way to the northeast corner." NCSTAR IA, p. 20 [pdf p. 62]

Fire first appears on the north face of floor 12 about 80 feet from the north-east corner.

"By 3:00 p.m., the fire had spread internally past the northeast corner and onto the north face." NCSTAR 1A p. 20 [pdf p.62]

The fire spread internally to offices around column 79 and under the beams which allegedly underwent enough thermal expanion to push a girder off its seat and initiate the "global collapse" at 5:20 p.m.

Figure 5-119. Photograph showing the north face of WTC 7 taken from a helicopter around 2:57 p.m. +/- 5 min Figure

Figure 5-121. Cropped photograph of the north face of WTC 7, taken from a helicopter around 3:05 p.m. +/- 5 min

“In less than 15 min, the fire simultaneously spread rapidly to the east to engulf the northeast corner of the floor and more slowly westward about one-third of the way across the north face.” NCSTAR 1a P. 20 [PDF P.62]

Figure 5-135. Cropped photograph showing the east edge of the north face and an oblique view of the east face. It was likely taken between 3:20 p.m. and 3:40 p.m.

"The fire continued spreading westward in starts and stops, approaching the northwest corner of the floor around 3:45 p.m." NCSTAR 1A p. 20 [pdf p. 62]

Figure 5-136. Frame taken from a video shot from near the corner of Greenwich Street and Park Place showing the north face of WTC 7 between 3:49 p.m. and 3:54 p.m.

The photographs reveal that the fire on floor 12 had progressed from the south side of the building to the north side by 3:00 p.m. – and had engulfed the northeast corner by about 3:15 p.m. This means that the fire in the area in question (around column 79 and under the beams and girder in the northeast corner) had burned out at about 3:50, because as noted above, the fires burned for only about 20 to 30 minutes in any given location.

References:

NCSTAR 1A

NCSTAR 1-9 Vol.1 and 2

Part IIC

Numerous unscientific methods and fraudulent inputs NIST used to get the key girder to fail in their computer simulation.

NIST arbitrarily added 10% to the temperature results of their fire dynamics simulation (FDS).

"Case A used the temperature data as obtained from the FDS simulation. Case B increased the Case A gas temperatures by 10 percent." NCSTAR 1A p. 32 [pdf p. 74]

“only the fire-induced damage produced by Case B temperatures was carried forward as the initial condition for the building collapse analysis.” NCSTAR 1A p. 36 [pdf p. 78]

To get the shear studs on the floor beams to fail, NIST assumed high steel temperatures and applied the heat in 1 1/2 seconds over the entire north east part of floor 13. This method does not allow for heat dispersal or beam sagging.

NIST heated the floor beams but not the slab. Concrete expands at 85% the rate of steel and leaving this expansion out of the calculations that determined the failure of the shear studs is fraudulent.

"The girder and beam temperatures were assumed to be 500 °C and 600 °C, respectively, and the slab was assumed to remain unheated." NCSATR 1-9 Vol.1 p. 349 [pdf p. 393]

"Ramping of the temperatures for the beams and the girder then commenced at 1.1 s, leveling off at temperatures of 600 °C for the beams and 500 °C for the girder at 2.6 s. These temperature histories were prescribed uniformly for all nodes of the beams and the girder, respectively." NCSTAR 1-9 vol.1 p.352 [pdf p. 396]

"The first failures observed were of the shear studs, which were produced by axial expansion of the floor beams, and which began to occur at fairly low beam temperature of 103 °C. … When the beam temperatures had reached 300 °C, all but three shear studs in the model had failed due to axial expansion of the beams, leaving the top flanges of the beams essentially unrestrained laterally." NCSTAR 1-9 Vol.1 p. 352 [pdf p. 396]

"This analysis demonstrated possible failure mechanisms that were used to develop the leading collapse hypothesis further. The failure modes in this model were incorporated into the 16 story ANSYS and 47 story LS-DYNA analyses." NCSTAR 1-9 Vol.1 p. 353 [pdf p. 397]

In the NIST scenario, the collapse would have occurred at 4:00 PM.

NIST applied this arbitrarily increased temperature for 4 of hours heating, starting at noon. In their scenario, the damage and the collapse would have occurred at 4:00 PM.

"The choice of a 2 MW fire at 12:00 noon was a somewhat arbitrary initialization of the simulations, but there is little visual evidence of how the fires behaved in the time period between 10:28:22 a.m. and 2:00 p.m. … starting the calculations at noon was convenient in that the simulation time was the same as the actual clock time." NCSTAR 1-9 Vol.2 p. 377 [pdf p. 39]

NIST assumes that it took an hour and a half for the fires, started by burning debris from WTC 1 - 350 feet away, to develop into a 2MW fire.

"The building response is examined at 3.5 h and 4.0 h of heating. At 3.5 h, the floor systems had fire-induced damage and failures of some connections, beams, and girders. After 4.0 h of heating, there was substantially more damage and failures in the WTC 7 structural floor system, particularly in the northeast region surrounding Column 79. The structural condition at these two times illustrates how the structure developed sufficient fire-induced damage to reach the collapse initiation event." NCSTAR 1-9 Vol.2 p. 493 [pdf p. 155]

Building Response at 4.0 h

"On Floor 13 (Figure 11–35), all four of the north-south girders attached to Columns 79, 80, and 81 had failed, due to either buckling or girder walk off of the bearing seat at Columns 79 and 81." NCSTAR 1-9 Vol.2 p. 504 [pdf p. 166]

"Fire-induced thermal expansion of the floor system surrounding Column 79 led to the collapse of Floor 13, which triggered a cascade of floor failures. … This left Column 79 with insufficient lateral support, and as a consequence, the column buckled eastward, becoming the initial local failure for collapse initiation." NCSTAR 1A p. 22 [pdf p. 64]

NIST failed to account for beam sag that would have prevented the floor beams from expanding lengthwise more than 4.75 inches.

"A girder was considered to have lost vertical support when its web was no longer supported by the bearing seat. The bearing seat at Column 79 was 11 in. wide. Thus, when the girder end at Column 79 had been pushed laterally at least 5.5 in., it was no longer supported by the bearing seat." NCSTAR 1-9 Vol.2 p. 527 [pdf p. 189]

"The bearing seat at Column 79 was 11 12 in. wide. Thus, when the girder end at Column 79 had been pushed laterally at least 5.5 6.25 in., it was no longer supported by the bearing seat."

wtc7-i-beam-temp-v-sag

NIST ignored their own finding:

"Temperatures were uniform (within 1°C) across the bottom flange and web, but the top flange temperature was less by up to several hundred degrees because the slab acted as a heat sink." NCSTAR 1-9 Vol.2 p. 391 [pdf p. 53]

Thermal expansion would cause the bottom flange to expand more than the top flange forcing the beam to bow downward. The NIST hypothesis does not allow for downward bowing.

NIST finally released the structural and shop drawings in January of 2012 pursuant to a FOIA request. They can be downloaded here:

9/11 researcher David Cole went through the hundreds of drawings and found drawing 1091 which shows the girder seat was 12 inches wide (as noted above), not the 11 inches claimed in the final report. He also found drawing 9114, which shows flange stiffeners at the column 79 end of the girder between column 44 and 79.

NIST omitted these flange stiffeners that would have prevented the bottom flange from folding as required for their collapse to begin. The girder would have to be pushed almost all the way off the seat, not just half way, before the bottom flange would buckle.

“Walk-off failure of beams and girders was defined to occur when … the beam or girder was pushed laterally until its web was no longer supported by the bearing seat. … the beam was assumed to have lost support, as the flexural stiffness of the bottom flange was assumed to be insufficient for transferring the gravity loads.” NCSTAR 1-9 Vol. 2 p. 488 [pdf p. 150]

The flange stiffeners are on the Frankel drawings but not on the NIST drawings in the final report.

The fictitious “10-story gouge” claimed early on by NIST in WTC 7's south face is exposed.

I first noticed the conundrum that suggested that the “10-story gouge” in the side of WTC7 could not have actually existed back on September 6, 2006 while “debating” with Ryan Mackey at the JREF forum:

"middle 1/4 to 1/3 width of the south face was gouged out from floor 10 to the ground"

"No heavy debris was observed in the lobby area as the building was exited, primarily white dust coating and black wires hanging from ceiling areas were observed" NIST June 2004 Progress Report, Appendix L p. 18 [pdf p. 22]

Obviously, debris large enough to create a 10-story gouge, 1/4 to 1/3 the width of the building, would have landed in the 1st floor lobby along with everything it brought down, including the 3rd floor lobby.

NIST depicted this ‘damage’ in the graphic on pg 23 as “Possible region of impact damage” and again on pages 31 & 32 as “Approximate region of impact damage”

9/11 researcher Winston Smith found another quote that was in conflict with the 10-story gouge on page 20 of the FEMA report Chapter 5.

"According to the account of a firefighter who walked the 9th floor along the south side following the collapse of WTC1, the only damage to the 9th floor facade occurred at the southwest corner." FEMA, Chapter 5 p.20

Later I found two more quotes that were in conflict with the 10-story gouge. Chief Frank Fellini [in charge of operations at West and Vesey]: "…building number seven, which had taken a big hit from the tower. When it fell it ripped steel out from between the third and the sixth floors across the facade on Vesey Street."

Also on page 18 of NIST 2004 Progress report, Appendix L, was a well-obfuscated quote that was in conflict with the 10-story gouge. It is only after careful reading that it becomes clear:

"debris damage across one-fourth width of the south face, starting several floors above the atrium (extended from the ground to 5th floor*), noted that the atrium glass was still intact" NIST June 2004 Progress Report, Appendix L p. 18 [pdf p. 22]

*The atrium, not the damage, extended from the ground floor to the 5th floor. The “10-story gouge” would have taken out much of the atrium glass.

Post on the “10-story gouge” at the JREF Forum on April 10, 2007.

Knowing of these contradictions, Shyam Sunder still stated in Popular Mechanics’ article "Debunking the 9/11 Myths."

"Sundar: On about a third of the face to the center and to the bottom — approximately 10 stories — about 25 percent of the depth of the building was scooped out."

He stated this as if it were a fact.

Popular Mechanics (PM) says:

"NIST investigators believe a combination of intense fire and severe structural damage contributed to the collapse, though assigning the exact proportion requires more research."

Davin Coburn, editor/researcher for Popular Mechanics, told Charles Goyette in this radio interview that he had seen a photo of the 10-story gouge

Coburn: "When the North Tower collapsed … there was damage to Building 7 … What we found out was … about 25% of the building’s south face had been carved away from it …"

“We have seen pictures that are property of the NY Police Department and various other governmental agencies that we were not given permission to disseminate …”

Goyette: "Popular Mechanics got to see them, but the average American citizen can’t see them."

Coburn: "Correct."

Final post on the "10-story gouge" at the Loose Change forum on November 14, 2007:

In the final report on WTC 7, the debris damage from WTC 1 is shown in this graphic.

The 10-story gouge – middle 1/4 to 1/3 the width of the south face from floor 10 to the ground – as shown in Figure L-31 above, is not there.

NCSTAR 1-9 vol. 2

NIST’s fraudulent diesel fuel fire hypothesis is exposed.

FEMA acknowledges the problem with the diesel fuel fire hypothesis:

"Although the total diesel fuel on the premises contained massive potential energy, the best hypothesis has only a low probability of occurrence. Further research, investigation and analysis is needed to resolve this issue." FEMA Chapter 5 p. 31 – May, 2002

NIST continues the diesel fuel fire hypothesis despite having the data that proved it did not exist.

"The presence of a fuel distribution system and the possibility of damage at the south face from WTC 1 debris impact, indicates that fires may have been present on Floor 5." NIST June 2004 Progress Report, Appendix L p. 51 [pdf p. 55]

Shyam Sunder misinforms Popular Mechanics in the article “Debunking The 9/11 Myths” by telling the writers that there was a fire on floor five of WTC7 that lasted up to seven hours. There was no fire reported on that floor and no reason to think there was one.

PM: "Second, a fifth-floor fire burned for up to 7 hours. "There was no firefighting in WTC 7, Sunder says. Investigators believe the fire was fed by tanks of diesel fuel that many tenants used to run emergency generators. Most tanks throughout the building were fairly small, but a generator on the fifth floor was connected to a large tank in the basement via a pressurized line. Says Sunder: "Our current working hypothesis is that this pressurized line was supplying fuel for a long period of time."

"This finding allows for the possibility, though not conclusively, that the fuel may have contributed to a fire on Floor 5." NIST Part IIC April 5, 2005 p.38

In early 2007, the ‘diesel fuel fire’ debate was about the 40,000 gallons of diesel fuel. No one had researched the details of the diesel fuel fire hypothesis.

The FEMA Chapter 5 report contains a great deal of basic information about WTC 7. All the tanks, pipes and generators were in the west end of the building, except for the 4 SSB generators in the north east section of floor 5. The supply line to these generators was the only possible source of a fuel oil fire in the east end of WTC 7 where the collapse began.

The following is from my post at the JREF forum on March 7, 2007:

"There were no diesel fuel-fed fires in the east part of WTC 7 where the initiating event ocurred that led to the collapse."

The east generator room was in the north east corner of WTC 7 on the 5th floor.

"The supply pipe for the east generator room was north of the wall that is on the north side of the core area, about 90' from the south side of the building." [FEMA p. 14 - 15]

"If the generators [and the pump feeding fuel oil to them] were running, the louver vents would be open." [FEMA p. 29] If there was a fire in this room, smoke would be pouring out thru the vents. Full post: " "

The following is from my post at the Loose Change Forum on Nov. 15, 2007:

"The north east generator room was in the NE corner of WTC 7 on the 5th floor. The supply pipe for the generator room was north of the core area, about 90 feet from the south side of the building and at the opposite end of the building from where the debris damage was. All the other diesel tanks, pumps, supply pipes and generators were in the west half of WTC 7.

If the generators were running, and the intake/cooling fans were on the louver vents would be open.

If there was a fire in this room, smoke would be pouring out through the cooling air exhaust vents. If the louvers were closed, a fire would not have sufficient oxygen to burn hot enough to be a factor in the collapse."

Full Post:

NIST concedes the diesel fuel fire hypothesis on December 18, 2007 p. 6

"The working hypothesis is based on an initial local failure caused by normal building fires, not fires from leaking pressurized fuel lines or fuel from day tanks."

In the final report NIST paraphrases my final post 13 times.

NCSTAR 1-A Final Report on WTC 7

"An under-ventilated fire, in which the air handling system was turned off and the louvers were closed. The initial fuel burning rate was fit to the air availability. Result: The sustained air temperatures were not high enough to compromise the structure." p. 30 [pdf p. 72]

An under-ventilated fire, in which the air handling system was turned off, but the louvers were open. Result: Smoke would have exhausted through the east louvers, and the imagery showed no such effluent.

"The worst-case scenarios associated with fires being fed by the ruptured fuel lines, (b) would have produced large amounts of visible smoke that would have emanated from the exhaust louvers. No such smoke discharge was observed.” p. 49 [pdf p. 91]"

“Simulation of hypothetical, worst-case fire scenarios on these floors showed that pool fires, associated with ruptured diesel fuel lines, (c) would have exhausted smoke from the exhaust louvers, which was not observed. p. 51-52 [pdf p. 93-94]

NCSTAR 1-9 Vol.1

"However, if a large fire penetrated a plenum wall and if the louvers were open, flames might have been visible, and smoke might have emanated from the exhaust openings. NIST found no photographic records or eyewitness accounts of smoke or fires that could be attributed to fires on these two floors." p. 51 [pdf p. 95]

"Simulations showed that pool fires associated with ruptured diesel fuel lines… (c) would have exhausted smoke from the exhaust louvers, in conflict with the photographic evidence which showed none." p. 355 [pdf p. 399]

NCSTAR 1-9 Vol.2

"Result: The FDS simulation showed that the natural flow from the fire plume would have been out of the louvered openings on the east side of the building in a very short time. Significant plumes of smoke would have been seen emerging from the building within a few minutes of ignition, contradicting the visual evidence." p. 372 [pdf p. 34]

"A broad range of hypothetical, extreme fires on the 5th floor did not produce a fire scenario that was consistent with the visual evidence that would have threatened the load bearing capacity of Columns 79, 80, or 81." p. 374 [pdf p. 36]

"these fires would have exhausted smoke from the exhaust louvers. No such emanation was observed." p. 386 [pdf p. 48]

"Additionally, such fires would have produced large amounts of visible smoke that would have emanated from the exhaust louvers; however, no such smoke discharge was observed." p. 605 [pdf p. 267]

"fires being fed by the ruptured fuel lines… would have produced large amounts of visible smoke that would have emanated from the exhaust louvers. No such smoke discharge was observed.”" p. 619 [pdf p. 281]

"The worst-case fire scenarios associated with fires being fed by the ruptured fuel lines (b) would have produced large amounts of visible smoke that would have emanated from the exhaust louvers. No such smoke discharge was observed."

"Simulation of hypothetical, worst-case fire scenarios on these floors showed that poof fires associated with ruptured diesel fuel lines, (c) would have exhausted smoke from the exhaust louvers, which was not observed." p. 621-622 [pdf p. 283-284]

NIST’s claim in its Final Report about the lack of shear studs on the floor support girder between columns 44 and 79 is exposed.

By Chris Sarns & Judy Shelton - November 9, 2008

The NIST Final Draft on the collapse of World Trade Center building 7 has many flaws, including blatant fraud.

In their June 2004 report (and in the actual shop drawings*), NIST referred to the use of shear studs in World Trade Center 7. Shear studs are used to keep steel floor beams and girders in place; they impart stability and strength to buildings. But in their August 2008 final report, NIST re-worded their comments on shear studs to make it appear that none were used on the floor girders.

Why would they do this? To know the answer, you need to understand NIST’s collapse theory. This is how it goes:

The key girder between column 79 and the exterior wall fails at floor 13. Its failure causes the collapse of floors 13 through 6 Column 79, now unsupported laterally by these floors, buckles and brings down the entire building.

This scenario is easier to posit if the key girder isn’t being held firmly with shear studs. Thus, in the August 2008 report, NIST did what it had to do to make it more reasonable that the girder would fail: It magically omitted the shear studs.

Compare these two paragraphs. In the excerpted paragraph of the 2004 report, NIST says that studs were used with both beams and girders, although the studs “were not indicated on the design drawings for many of the core girders” (the girder associated with column 79, by the way, was not a core girder). In the 2008 report, however, not only does NIST drop the association of girders with shear studs ( first sentence of excerpted paragraph), but then they go on to imply that studs were not indicated at all on the girders (last sentence of excerpted paragraph):

June 2004 NIST app. L pg 6 [pdf pg 10]

"Most of the beams and girders were made composite with the slabs through the use of shear studs. Typically, the shear studs were 0.75 in. in diameter by 5 in. long, spaced 1 ft to 2 ft on center. Studs were not indicated on the design drawings for many of the core girders."

August 2008 NCSTAR 1-9 vol.1 pg 15 [pdf pg 59]

"Most of the beams [the words "and girders" are deleted] were made composite with the slabs through the use of shear studs. Typically, the shear studs were 0.75 in. in diameter by 5 in. long, spaced [the words "1 to" are deleted] 2 ft on center**. Studs were not indicated on the design drawings for [the words "many of the core" are deleted] the girders."

Then, in this paragraph of the 2008 report, they use the “absence” of shear studs to help make their case:

August 2008 NCSTAR 1A pg 49 [pdf pg 87]

"At Column 79, heating and expansion of the floor beams in the northeast corner caused the loss of connection between the column and the key girder. Additional factors that contributed to the failure of the critical north-south girder were (1) the absence of shear studs that would have provided lateral restraint and (2) the one-sided framing of the east floor beams that allowed the beams to push laterally on the girders, due to thermal expansion of the beams."

This deliberate distortion of the evidence can only be called fraud. Even those who have accepted the official story must acknowledge that NIST’s misstatements of its own report are not mistakes. They are bending the facts to accommodate a theory that cannot, so to speak, stand up.

*NCSTAR 1-9, Vol. 2, Fig. 12-4

** “on center” – a term that means “apart”

Structural engineer, Ron Brookman found that the Salvarinas “Fabrication and Construction Aspects” a document that outlines the basic structural system of WTC 7, shows 30 shear studs on the girder in question.

The erection drawings show field-installed studs on the beams but not the girder between columns 44 and 79, leaving open the possibility that they were installed in the fabrication shop before being brought to the site. A note on the drawing says "For additional studs see cust. dwg. S8," but the corresponding note has been erased.