NYC-WTC_000186589

NYC 9/11 Public Portal Document

Sampling Plan Revision Drafted December 11. 2001 t

Eliminate samples for acids, aldehydes, PAHs, and aromatics. We are not finding any of these at any significant levels. If Bob Adams objects to this, I am going to suggest the use of passive monitors for aromatics and aldehydes to cut down on the time the techs have to spend doing calibrations.

Emphasize sampling for silica during concrete drilling and other concrete work. We have not found high levels &om these jobs, but OSHA has.

Put hydrogen sulfide monitoring on the routine sampling plan. There have been periodic H2S odor complaints at the southwest comer of the site. We believe that this is coming from a storm sewer in that area, but have not been able to pin down the source. Area samples have been collected, but I think we should also do personal sampling of people working in that area. ATC is also making direct reading measurements in this area.

Begin doing regular noise monitoring. There is increased use of chain saws (for cutting wood for shoring), jackhammers and concrete saws and drills as the excavations get lower. Hearing conservation has not been an item of emphasis in the past, but it needs to get more attention now.

Further reduce the number of asbestos samples. Fiber counts are low and there is not much prospect of this increasing.

Keep the same sampling plan for metals, diesel fume, carbon monoxide and ozone.

# Samples per Week ■ Analyte Original Plan CurrentPlan;; ;'NewTl^.O2.

Carbon Monoxide 28 22 (minimum) 22 (minimum) Asbestos 42 15.5* 10 Total Dust & Metals 42 9 9 Respirable Dust and Silica 12 7.25* 10 Aromatic Hydrocarbons 8 14 0 PAHs 8 8 0 Aldehydes_____________ 8 7.5* 0 Ozone 4 5.5* 5.5* Diesel Exhaust 4 7.5* 7.5* Acid Scan 0 13.5 0 Hydrogen Sulfide_______ 0 As Needed 6 Mercury 0 As Needed 5 Noise 0 As Needed 12

Total 156 109.75 109.75

* Fractional numbers indicate that some jobs are sampled less than once per week

CITY_21MC100_002948066

NYC-WTC_000186589