Document label for 10 Cortlandt Street

NYC 9/11 Public Portal Document

Hillmann Environmental Group, LLC

SECTION 1 — EXECUTIVE SUMMARY

1.1 General

On October 19, 2002, Mr. Craig Downs, Mr. Shane Bielawski and Ms. Jennifer M. Brown, IHT, of Hillmann Environmental Group, LLC (Hillman), conducted a follow up limited Environmental Health Risk Assessment of 22 Cortlandt Street, New York, NY. An EHRA was performed throughout 22 Cortlandt Street in response to the collapse of the World Trade Center in February 2002. This assessment was performed as a follow up to the original EHRA in response to tenant and building management (i.e. Cushman and Wakefield) concerns to ensure that the indoor air quality is currently at acceptable standards.

Hillmann's site investigator performed a visual inspection for selected conditions that could negatively impact indoor air quality. The investigator measured temperature, relative humidity, carbon dioxide, carbon monoxide, respirable dust, mercury and collected samples for volatile organic compounds, , PCBs, dioxins, fungal spores, total dust, and asbestos.

1.2 Findings

• On the day of the investigation, inside the building, temperature and relative humidity readings were collected. Temperatures ranged from 67°F to 74°F and relative humidities ranged from 36% to 50%. 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 were below the recommended range. Relative humidities were within the recommended range.

• Observed carbon dioxide levels in the subject space ranged from 506 ppm to 741 ppm. ASHRAE recommends that carbon dioxide levels remain below an outdoor reading plus 700 ppm. Since the outdoor reading was 390 ppm, the recommended limit is 1090 ppm. Carbon dioxide levels were below the recommended limit.

• Measured carbon monoxide levels ranged from 0 ppm to I ppm in the subject space. These levels are below the Environmental Protection Agency (EPA) National Ambient Air Quality Standard (NAAQS) of 9 ppm,

• For respirable dust, the American Conference of Governmental Industrial Hygienists (ACGIH) recommends a Threshold Limit Value (TLV) of 3.0 mg/m3 and the Occupational Safety and Health Administration (OSHA) has a Permissible Exposure Limit (PEL) of 5.0 mg/m' Respirable dust levels ranged from 0.017 mg/m3 to 0.66 mg/m3. Dust levels were below the recommended limits in the subject space.

• The American Conference of Governmental Industrial Hygienists (ACGIH) recommends that dust levels remain below 10 (check this first) mg/m'. The total dust amounts ranged from below the limit of detection of LOD to 0.083 mg/m3.

• Mercury vapor levels were measured in the subject space and remained below the limit of detection of 0.001 mg/m` and therefore below the ACGIH recommended limit of 0.025 mg/m'.

22 Cortlandt Street/New York. NY/Project Number Y2-1458 Page I

NYC-WTC 000126262