National Institute of Standards and Technology (NIST)

National Construction Safety Team Advisory Committee (NCSTAC)

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NIST NCSTAC 2023 Annual Report to Congress

December 18, 2023

The Honorable Frank Lucas

Chairman

Committee on Science, Space, and Technology

United States House of Representatives

Washington, DC 20515

Dear Mr. Chairman:

We are pleased to submit the 2023 Annual Report of the National Construction Safety Team 

Advisory Committee (NCSTAC/the Committee) of the National Institute of Standards and 

Technology (NIST). The Committee serves as NIST’s advisor on implementation of the National 

Construction Safety Team (NCST) Act (P.L. 107-231; the ‘Act’), and the opinions and 

recommendations expressed in this letter reflect our views as an independent body composed of 

technical experts in engineering, public health, and the social sciences. 

The Act directs the Committee to report to Congress annually on its findings and recommendations 

in two areas:

1. Evaluation of NCST activities, and

2. Assessment of the implementation of recommendations of NCST and the Committee.

The Act was passed in response to the coordinated attacks of September 11, 2001. Following the 

collapse of the World Trade Center towers, NIST conducted a groundbreaking study of building 

performance and issued transformative, evidence-based recommendations for improvements in 

building codes and standards. Prior to 9/11, NIST had already distinguished itself as a leading 

federal agency with a history of rigorously investigating disasters of various types, going back at 

least as far as the 1971 earthquake in the San Fernando Valley. The passage of the Act solidified 

and now facilitates NIST’s ability to conduct such investigations and enhances cooperation with 

other federal agencies.

On August 9, 2022, a change in the Act was approved. The change requires NCST’s cooperation 

with civil litigants provided such cooperation does not compromise NCST’s investigation or 

preservation of evidence. This change is an important step toward timely and just resolution of 

civil suits arising from events that NCST chooses to investigate.

Under H.R. 4143, amendments to the Act are proposed to expand the safety team’s authority to 

investigate failures of infrastructure and structures other than buildings. NCSTAC applauds this 

proposed change, which is consistent with a 2022 recommendation from the NCST Advisory 

Committee. The amendment would formalize NCST’s authority to evaluate damage to 

infrastructure, in addition to buildings, from natural disasters. Investigation of natural disasters, 

including hurricanes and wildfires, has been the primary focus of the NCST over the last decade. 
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National Construction Safety Team Advisory Committee (NCSTAC)

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The frequency and severity of natural hazard events have increased, particularly those related to 

atmospheric conditions, therefore making the NCST’s work even more urgent.

This year the committee met on June 14-15, 2023, and again on September 7, 2023. During these 

meetings, NIST staff briefed the Committee on activities performed under the Act and closely 

related activities performed by NIST under other authorities. The Committee also took this 

opportunity to ask NIST staff and research team members questions and to provide feedback on 

their many ongoing activities. These meetings, as well as our review of presentation slides and 

other available documents, helped to inform this annual report. 

Throughout this report, we use bold typeface and indented text to highlight our recommendations.

NIST’S RESPONSE TO THE RECOMMENDATIONS IN THE COMMITTEE’S 2022 

REPORT TO CONGRESS

General Comments

2022 Recommendation 1. We recommend that NIST takes advantage of its agreement 

with the National Science Foundation (NSF)-funded Natural Hazard Engineering Research 

Infrastructure (NHERI) by exploring more specifically how these programs can cooperate.

The NCSTAC is pleased that NIST is using their recently established interagency agreement with

the NSF. To date, NIST has issued two work orders, one to the NSF-sponsored NHERI 

experimental facility at the University of Texas-Austin, to utilize a shared-use mobile shaker and 

associated personnel, and one with the University of Washington to expand a NHERI RAPID

project to use shared-use equipment to collect perishable data following the Champlain Towers 

South collapse. NIST has also issued a work order to organize a data synthesis workshop.

2022 Recommendation 2. In addition to NIST’s crucial work on tornado effects on highimpact buildings, we encourage additional efforts to broaden recommendations for design 

guidelines for tornado effects to include additional classes of buildings and other structures. 

The NCSTAC is pleased that NIST collaborated with FEMA to develop and publish a 21-page

FEMA/NIST fact sheet in early 2023, titled “Improving Windstorm and Tornado Resilience: 

Recommendations for One- and Two-Family Residential Structures.” NIST has also begun a 

longer-term research and development effort to identify tornado resistant design options, evaluate 

associated benefit/cost ratios, and develop design guidance and code change proposals for Risk 

Category II buildings (common structures, such as the aforementioned residential structures, that

are not considered essential facilities). We encourage NIST to continue in this direction, so that 

their guidance can encompass both high impact buildings such as schools and hospitals and these 

more common buildings. 
National Institute of Standards and Technology (NIST)

National Construction Safety Team Advisory Committee (NCSTAC)

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Hurricane Maria NCST Investigation

2022 Recommendation3. We encourage NCST team members to continue their 

collaborative work in developing a standard protocol for conducting verbal autopsies.

NCST investigations, specifically, and mortality studies, in general, will greatly benefit from the 

verbal autopsies that NIST has been spearheading as part of their Hurricane Maria investigation. 

The Committee applauds NIST and their collaborators for their efforts, which we understand will 

contribute significantly to the development of standard protocols for conducting verbal autopsies.

2022 Recommendation 4. Conclusions of the Hurricane Maria study should emphasize 

that loss of building function, a key measure of resilience, depends not only on structural 

damage, but also on other building systems and surrounding critical infrastructure.

The NCSTAC is pleased to learn that loss of function -of building systems and surrounding 

infrastructure (particularly those that are critical to recovery) are a major part of the ongoing NIST 

studies. We encourage the NCST to continue to develop and share these efforts. 

2022 Recommendation 5. It may be useful to consult Spanish language speakers who are 

native to Puerto Rico and can comment about potential language-related nuances for the 

Hurricane Maria study.

The NCSTAC is pleased to learn that, to ensure the best quality outcome, high quality translation 

by certified translators, along with independent review, has been a high priority in the development 

of Spanish language data collection instruments and in translation of Spanish language responses 

into English. We encourage the NCST to continue consulting with people who are Spanish 

speakers native to Puerto Rico, given the linguistic and cultural nuances that will need to be 

considered in the presentation of the research findings. 

Champlain Tower South Partial Collapse NCST Investigation

2022 Recommendation 6. The Committee recommends careful attention to the following 

highly challenging elements of this historic investigation:

• NCST is advised to pursue all potentially valuable information that may not be tied to 

physical evidence and that can only be gained through interviews. It is also important 

to consider that some memories may be quite perishable over time.

NCST has been collecting all information through interviews that may otherwise be lost if not tied 

to physical evidence. The Committee applauds NIST for expanding their number of social science 

investigators and accelerating the collection of qualitative interviews by using innovative 

strategies. 
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• Regarding the review of the Champlain Towers South structure, it would be very useful 

to find a set of calculations for a similar building in South Florida designed in the late 

1970s or early 1980s; such a set would help establish probable design practices and the 

standard of care.

The NCST has searched for such calculations but has not yet found a set. They are continuing their 

efforts in this regard. 

• With respect to the structural testing of replicas of critical elements of the structural 

system, we recommend that NCST recognize the uncertainty of pre-collapse conditions 

and conduct tests on specimens that represent a reasonable range of probable 

conditions.

The NCST has agreed that uncertainty is an important aspect of the investigation, and all analyses 

will include probabilistic considerations.

• The computational models and laboratory test results should be adjusted to reflect the 

effects of long-term sustained load, which are difficult to simulate in the laboratory 

tests.

The investigation includes long-term effects of sustained loads, such as concrete durability, aging,

and reinforcement corrosion.

2022 Recommendation 7. Considering the significance of the collapse and its potential 

impact on the U.S. and global construction industry, we urge NCST to expedite their 

investigation and issue interim summaries of critical lessons learned as the investigation 

progresses.

NIST has developed a communication plan and intends to share all data allowed within the limits 

of privacy laws. NIST has also been very sensitive to the needs of bereaved survivor communities 

in terms of their communications protocols. Recommendations can only be disclosed at the end of 

the study and release of the final report; however, NIST will share relevant pieces of information 

as allowed throughout the study. 

With this balance among openness and the sensitivity and security of the data in mind, the 

Committee encourages the NCST—in accordance with recent guidance from the White House 

Office of Science and Technology Policy regarding open science and the public good—to make 

appropriate data and findings available without delay. 

UPDATES TO THE DISASTER AND FAILURE STUDIES PROGRAM

Event scoring, to measure the significance of building failures to help determine the focus of 

disaster investigations, is an important function of the Disaster and Failure Studies Program

(DFSP). In FY2023, NIST scored 19 domestic and international events, comprising five tornados, 

one hurricane, six earthquakes, one wildfire, and six structural failures. Two of these scored high 
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National Construction Safety Team Advisory Committee (NCSTAC)

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but occurred in other countries where the lessons to be learned for the United States were judged 

minimal (a small team traveled to Turkey after the February 2023 earthquake to conduct 

preliminary reconnaissance with a larger team from the American Concrete Institute). Three 

domestic events were considered seriously for potential deployment, and two were not selected for 

further investigation because they lacked broad implications for codes and standards. The third 

was the Hawaii wildfires, for which a NCST reconnaissance team went to Maui. This event is still 

being considered for a NCST designation, but now constrained by NCST’s fiscal and personnel 

resources, since NIST currently has two NCST investigations ongoing. 

DFSP Recommendation 1. Due to the important implications of wildfires for the entire 

nation, especially considering the recent increases in climate-impacted atmospheric natural 

disasters, we highly recommend that NIST remain involved in the study of the Hawaii 

wildfire disaster and coordinate with the other federal, state, and local authorities that are 

investigating the event. This involvement with authorities, viewed as a potential next step 

by the NCST, is fully encouraged by the Committee.

We are pleased to see NIST’s progress on staff safety training and other activities to encourage a 

culture of “team readiness” to facilitate a quick deployment into the field for reconnaissance 

activities. 

DFSP Recommendation 2. We encourage the team to continue the emotional and mental 

health support to investigatory team members, especially those who rotate in and out of 

lengthy shifts in the field.

NIST’s NCST received a $40M disaster supplemental for “Scientific and Technical Research and 

Services” to enhance its work on the impacts of hurricanes, typhoons, and wildfires. This 

supplemental funding to NCST allows it to continue important investigations such as the 

Champlain Towers South study, coordinating a study of Hurricane Fiona with the Hurricane Maria 

study, and a new study on Hurricane Ian.

HURRICANE MARIA NCST INVESTIGATION

Overview of the Hurricane Maria Investigation

The investigation has two major components, the NCST investigation and the National Windstorm 

Impact Reduction Program (NWIRP) investigation. These two investigations generated seven 

technical projects: (1) Hazard Characterization, (2) Performance of Critical Buildings, (3) Public 

Response to Emergency Communications, (4) Morbidity and Mortality, (5) Impacts to and 

Recovery of Infrastructure Systems, (6) Recovery of Business and Supply Chains, and (7) 

Recovery of Social Functions. These technical projects have been developed with the support of 

several federal, state, local, and territorial agencies. At this point, all the data collection for the 

NCST portion of the investigation has been completed, and most of the data collection has been 

completed for the NWIRP portion.

According to the Hurricane Maria NCST investigators, the draft of the final report should be 

available for review by fall of 2024, with the final report to be ready for release in 2025. We 
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applaud the monumental efforts of this team. Considering the importance of the results generated

by these studies, we encourage the research team to continue meeting their deadlines to ensure that 

these important data and findings are broadly shared with the public. 

CHAMPLAIN TOWERS SOUTH PARTIAL COLLAPSE NCST INVESTIGATION

Overview of the Champlain Towers South Investigation

In the two years since Chaplain Towers South (CTS) collapsed, the NCST has substantially 

progressed with its comprehensive study of potential causes of this tragic failure. Based on our 

discussions with NCST, we believe the effort is well organized, focused, and extremely 

comprehensive. This establishes high expectations that the NCST will identify the salient causes 

and propose fundamental changes in practice, if any are needed, to reduce the chances that another 

catastrophic collapse like this will occur in the future. 

NIST and NCST should be commended for designing a rigorous technical approach, which 

includes a process for the engineers to request assistance from the social scientists on the team to 

gather information that augments the story being told by the building debris. 

CTS Recommendation 1: The internal NIST investigation process should encourage bidirectional exchange so that information gleaned by the social science team might also spur 

additional evidence gathering by the engineers. This model shows great promise for future 

investigations. 

NCSTAC admires how NIST and NCST have established a plan to communicate findings to 

impacted family members prior to releasing information publicly. We commend the NCST’s

diligence and efficiency in the wide and extended-duration range of research activities, but we also 

applaud their dedication to ethical communication as a vital component for establishing and 

keeping public trust in the process.

With the above in mind, we also acknowledge that intense interest—particularly from family 

members and other members of the public directly impacted by the collapse—in the ultimate 

findings of this thorough investigation is generating frustration over its duration. With the 

expectation that the final report might not be released until 2025, this frustration is likely to grow. 

CTS Recommendation 2: NIST should maintain its public communication practice so 

that interested parties learn about the NCST’s progress and findings at the earliest 

appropriate time.

Obstacles Faced by the NCST

NCSTAC acknowledges the efforts that the NCST investigation team has made in collecting, 

preserving, and managing the evidence necessary to evaluate multiple hypotheses for the collapse 

mechanism at Champlain Towers South. Indeed, NCST reports that investigators worked 18-hour 
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days, overlapping the two 12-hour response operational periods for 7 days/week for 2 months to

preserve perishable data. This has been an extraordinary demand on them. 

For current and future work in Florida, NIST has retained local consultants to work with members 

of the NCST, thereby alleviating some of the pressure going forward. The NCSTAC thanks the 

NCST for their efforts, while acknowledging that such a grueling work schedule is not personally 

or professionally sustainable and could become counterproductive to the overall effort if members 

of the team are not able to continue at this pace. 

CTS Recommendation 3: NCSTAC suggests that NIST continue to explore options to 

reduce the demand on investigators during future deployments, including retaining 

consultants based close to the event site, as appropriate, as NIST has done recently for the 

ongoing CTS investigation.

NCSTAC recognizes that the NCST has faced challenges in procurement of contracts and 

resources, due to Federal acquisition regulations. These regulations have remained an impediment 

to quick and efficient progress across all the NCST investigations, even though NIST was granted

some expanded purchasing authorities to address this obstacle and accelerate some of the activities. 

Given the perishability of data necessary for understanding the built and social environment in a 

disaster context, such restrictive regulations inhibit timely data acquisition, preservation, and 

analysis, and consequently hinder and delay the reporting of findings.

Nevertheless, NIST and NCST leadership have been exceptional in their ability to proceed with 

investigations given the challenges of contracting and acquisitions per federal regulations. While 

the expanded authorities given to NIST have been helpful to the investigation and have allowed 

the preservation of perishable evidence necessary to the investigation, the NCSTAC was 

disheartened to learn that these expanded authorities ended on September 30, 2023, and that an 

extension has not been granted. 

CTS Recommendation 4: We recommend that NIST Disaster and Failure Studies Program

continue to investigate strategies to partner with organizations that have quick access to 

resources necessary for success and to consider opportunities to amend the Act so that the 

temporary purchasing authorities provided in an emergency can be maintained as part of 

the common operations. This is vital to ensure that the collection of perishable data moves 

forward. 

Progress on Finding the Cause of the CTS Collapse

An essential goal of the NCST is to identify the causes of the collapse. Knowing the failure 

mechanism quite specifically gives solace and understanding to survivors and the families of 

victims. It also could reveal potential risks in other existing buildings and methods to mitigate 

those risks going forward. Several failure hypotheses have been identified and are being carefully 

investigated and documented. As of our last meeting in September 2023, none had been 

eliminated. 
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During our meetings, the NCST described a prominent hypothesis related to the pool deck, to 

demonstrate progress toward identifying the cause of the failure and to show how the results of all 

the tasks underway, in combination, reveal evidence to support or eliminate hypotheses. For 

example, significant conditions under study in the pool deck adjacent to the high-rise portions of 

the building that collapsed include design understrength based on applicable original building 

code; misplaced top slab reinforcement reducing flexural strength capacity of the slab; heavier and 

more extensive planters on top of deck, various layers of fill and paving; and corrosion of slab 

reinforcement in different areas.

Significant investigation tasks remain, including sampling and testing of specimens from the 

evidence facility as well as laboratory tests of replicas of building elements involved in the 

collapse.

CTS Recommendation 5: When the NCST identifies hypotheses that are of sufficiently 

low probability of explaining the failure, it should substantially curtail additional study of

those hypotheses, to preserve resources for the testing of more prominent ones. 

NCSTAC Conclusions Regarding the Champlain Towers South Investigation

NCST is conducting a comprehensive and competent investigation of a highly complex and tragic 

building failure that killed 98 people and now stands as one of the deadliest building failures in 

our national history. They have engaged top experts in the disciplines that are essential to the 

collection and assessment of the available evidence from the debris, witnesses, and other sources. 

NIST and NCST are executing a thorough study that should yield incontrovertible findings.

In meetings in June and September 2023, NCST outlined the timeline for future work, with the 

expectation that technical work likely will be completed in late June 2024 and the final report 

issued a year after that. The schedule has been extended slightly due to conditions out of NIST’s

control.

SUMMARY

NCSTAC met with NIST twice to review progress on initiatives over the past year and to provide 

feedback to NIST. Based on our discussions with NIST, we make the following observations:

The NCST program is highly valuable to the safety and resilience of the built environment—and 

the people who occupy it—in the United States.

We commend NIST for diligently administering the NCST program and developing and 

maintaining an extraordinary technical workforce.

The NCST teams investigating Hurricane Maria and the Champlain Towers South collapse are 

making appropriate progress toward completion of their assignments, using comprehensive stateof-the-art investigative tools and techniques.
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NIST and the NCST teams have been responsive to feedback from the NCSTAC.

Sincerely yours,

José M. Izquierdo-Encarnación

Chair, National Construction Safety Advisory Committee

Ross Corotis

Past Chair (2022-2023), National Construction Safety Advisory Committee