Industrial hygiene elevated exposure notice, March 2002

NYC 9/11 Public Portal Document

✓ INDUSTRIAL HYGIENE ELEVATED EXPOSURE NOTICE

Date: 03/05/2002

To: Ray Master

CC: DDC- Bob Adams LMIG- John Rabovsky ATC- Mike Donovan LMIG- IH File

From: Mike Ramsey

RE: Elevated Exposures

Ray,

Attached are Elevated Air Sample Result Notifications for samples analyzed on 3/1/02 and 3/4/02. Elevated exposures are defined as above 50 % of the shift adjusted time weighted average (TWA) Occupational Exposure Limit (OEL) for the purpose of this notification. These are provided to you for distribution. You indicated that you will provide these to the contractor involved. The contractors affected were;

• EROC • Nicholson • Safeway Environmental • Tully

The following is a summary of the elevated exposure information that is attached;

• A quartz concentration of 15000% and a respirable dust concentration of 204% of the shift adjusted OEL on a Brokk operator in WTC 6, level B5. To my knowledge, this is the highest quartz exposure found so far on the site and it exceeds the protection of even full face-piece respirators, which have a nominal fit factor of 50.

• A quartz concentration of 117% of the shift adjusted OEL on a worker cleaning up debris at the Bl level of WTC 6.

• A quartz concentration of 117% of the shift adjusted OEL on a driver (Bobcat?) in WTC 6, LvI B2.

• A quartz concentration of 958% of the shift adjusted OEL on a driver (Bobcat?) tn WTC 6, LvI B2.

If future samples of Brokk operators indicate that the one sample result listed above is not an “outlier” and exposure can’t be reduced by other means, upgrading the respiratory protection beyond full face-piece respirators will be necessary for this job. The Brokk machines are equipped with remote control boxes and one obvious control is to assure that workers stand as far away from the breaker as possible. When

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