The samplers said otherwise.
Seven days after the towers fell, the head of the EPA told New York its air was safe. On that same day, an air sampler on South End Avenue caught asbestos at nearly eight times the federal action level. This week the City of New York released 170,000 pages of its own 9/11 records — including thousands of air-sampling results that sat, unread, in 68 boxes at the Department of Environmental Protection until August 2025. We mapped what the monitors actually recorded, from the City’s own hand samplers on September 12 onward: station by station, day by day.
An IVA Data Lab story · Built from the NYC Law Department’s 9/11 Document Portal · September 2026
Within days of the collapse, three governments strung a monitoring network across Lower Manhattan: the EPA’s Environmental Response Team at two dozen lettered street corners, New York State’s numbered stations from Park Row to a Coast Guard post at the Battery, and the City’s own DEP crews walking filters between Church and Broadway. What they caught is in the boxes the City just opened.
The EPA’s own draft evaluation, written in October 2002 and marked “DO NOT QUOTE OR CITE,” tabulates the exceedances: asbestos above the federal school-reoccupancy standard at Barclay & West Broadway on September 14 and 15, at Albany & West four times before October, at the wash tent on West Street into April 2002. Benzene at Greenwich & Liberty on September 28 hit 49 parts per million — forty-nine times the OSHA limit. Dioxin at the WTC Building 5 sampler ran above 160 pg TEQ/m³ for two weeks.
The earliest numbers in the boxes are the City’s own. Beginning September 12, DEP crews carried hand samplers to 41 locations from Worth Street to Battery Place and logged them on a map, every day, into February 2002. Their first sweep found 0.1 fibers/cc at Fulton & Church on September 13, ten times the residential standard, 0.08 at Chambers & Greenwich on September 12, and, in the October 2 table only, 0.22 on Murray Street at Church on September 13. By September 28 most readings outside the security zone were under 0.01, and the daily series run on through February 4, 2002. Those 2,727 readings are on the map, digitized from DEP’s own location maps and result tables, each location tagged with DEP’s zone code: open to the public, border line, or restricted zone.
Scrub the timeline. Each spike is one station on one day; height is the reading against its benchmark, red where it crossed the line. Switch pollutants with the chips. Click any station for its full record and the document it came from.
Two lines govern who gets help. The EPA’s 2002 residential cleanup program offered testing and cleaning to people living “south of Canal, Allen and Pike Streets.” The federal Victim Compensation Fund’s exposure zone runs along Canal Street to East Broadway, up East Broadway to Clinton Street, and east to the river. North of those lines, you were on your own.
The samplers did not respect the lines. The EPA’s own table of asbestos exceedances lists Public School 199 in Queens on October 12 and Site 2 at Chambers Street on October 9. The Staten Island landfill, where the debris went, exceeded the level on more than forty sampler-days through April 2002. The Canal Street post office was a monitoring station; nothing on the map says the dust knew to stop there.
By December 2001 the State and City were running an “Extended Network” of asbestos samplers on public school rooftops in every borough: PS 154 in the Bronx, IS 143 in Washington Heights, PS 274 in Bushwick, PS 44 on Staten Island, PS 199 in Long Island City — and more, logged day after day in DEP’s daily result sheets, most of them below detection.
That is the honest shape of the record: a city measuring itself, finding mostly clean filters far from the pile, and finding the exceptions exactly where the wind and the trucks went. The daily sheets are in the boxes; the ones the release includes are on the map.
“According to the Law Department, there are approximately 35,000 potential plaintiffs as a result of the events of September 11 and it is estimate[d] that 10,000 would file a claim.” Listed among the potential suits: “Health advisories caused individuals either to return to the area too soon (causing toxic exposure or emotional harm)” and “Rescue workers were provided with faulty equipment or no equipment (i.e. respirators).”
“If Nadler’s concerns are justified, we are not informing people of the real health risks in lower Manhattan, the City may face major public relations problems and is leaving itself open to a barrage of lawsuits. At the least we should discontinue telling people to clean their apartments with wet mops and rags.”
“I stressed that we would not use the word ‘risk’ in any letters as it would defeat the purpose of creating public confidence.” And earlier in the same page: “if we handled it with testing first in all instances, FEMA might balk at paying for a massive clean-up effort if testing only proved everything is fine.”
NYC-WTC_000148952) and link to the portal’s PDF.NYC-WTC_000148952). Marked “DO NOT QUOTE OR CITE” when written; released by the City as a public record. Stations from Table 1 and the Figure 21/22/33 keys; readings from Tables 3, 4, 6, 8–14 and the first-measurements table (p. 123–124). Values transcribed from OCR text and checked against the page images; two OCR-degraded cells are flagged in the data.NYC-WTC_000130550. Extracted programmatically from the portal’s OCR text; station names normalized; extraction ongoing.NYC-WTC_000150729) and the edition running through February 4, 2002 (NYC-WTC_000150708). The numbered locations were digitized from the October map by fitting its pixel grid to OpenStreetMap intersections (12 control points, 12.6 m RMS) and carried onto the February map (41 markers, 2.7 m RMS). The February tables were read by OCR from 300-dpi renders, rebuilt by series chronology, and checked against a hand transcription of the October edition and a random 16-cell image spot check. 2,727 readings, 2001-09-12 to 2002-02-04. Where the two editions disagree on a September value, the later edition is used. Positions carry about ±25 m.NYC-WTC_000138553) for the cleanup boundary. VCF NYC exposure zone statutory text, vcf.gov.NYC-WTC_000140138.