NYC-WTC_000220400

NYC 9/11 Public Portal Document

Hillmann Environmental Group, LLC

SECTION 1 - EXECUTIVE SUMMARY

1.1 General

On four dates, Ms. Jennifer L. Collins, IH of Hillmann Environmental Group, LLC (Hillmann), conducted an Indoor Air Quality Investigation at 44 Wall Street, New York, New York. The investigation is designed to identify indoor air quality contaminants as well as any residual effects from the recent World Trade Center Collapse.

Hillmann’s site investigator performed a visual inspection for conditions that could negatively impact indoor air quality. The investigator measured temperature, relative humidity, carbon dioxide, carbon monoxide, volatile organic compounds, hydrogen sulfide, oxygen, combustible gasses, and collected airborne asbestos fiber and bulk asbestos samples.

1.2 Findings

• On the days of the investigation, inside the building, temperature and relative humidity readings were collected. Temperatures ranged from 69°F to 78*’F and relative humidities ranged from 39% to 69%. The American Society of Heating, Refrigeration and Air-conditioning Engineers (ASHRAE) recommends that temperatures stay within the range of 66*’F to 76’’F and that relative humidities stay within the range of 30% to 60%. Temperatures and relative humidities were above the recommended range in some instances.

• Carbon dioxide levels ranged from 521 ppm to 1044 ppm. ASHRAE recommends carbon dioxide levels remain below an outdoor reading plus 700 ppm. The outdoor readings ranged from 521 ppm to 535 ppm, therefore the recommended limits were 1221 ppm to 1235 ppm. Carbon dioxide levels did not exceed the recommended range.

• Observed carbon monoxide levels ranged from below the limit of detection of 1 ppm to 2 ppm. These levels are well below the recommended limits, including the Environmental Protection Agency (EPA) National Ambient Air Quality Standard (NAAQS) of 9 ppm.

• Levels of volatile organic compounds ranged from below the limit of detection of 0.1 ppm to 7.4 ppm. Hillmann recommends that levels of volatile organic compounds remain below three times the background outdoor reading. Since the outdoor readings taken during the investigations were below the limit of detection of 0.1 ppm, the recommended limit would be 0.3 ppm. The only elevated reading occurred in the penthouse area during the time roof repair was occurring. This elevated level had returned to below the recommended limit on a follow-up visit.

• Hydrogen sulfide is a colorless gas with a strong odor that can often be present during or after a fire. The Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) is 10 ppm. In the subject space, levels were found to be below the limit of detection of 1 ppm. These levels were below recommended limits.

• The normal level of oxygen in air, at sea level, is 20.9%. If oxygen levels in a space are at or below 19.5%, the space is considered oxygen deficient (by OSHA 29 CFR Part 1910.94, 30 CFR Part 11 and ANSI Standard Z88.5-1973) and is unable to safely support human occupancy. The oxygen levels ranged from 20.7% to 21.2%, and were within normal levels.

Cushman & Wakefield/44 Wall Street, New York, NY/Project Number N3-7476 Page 1

CITY_21MC100_002388352

NYC-WTC_000220403