Document om5GBgnamxJ0bVjV1Jk4dYNeo

FILE NAME: Montello (MNT) DATE: 1976 May 24 DOC#: MNT004 DOCUMENT DESCRIPTION: Letter RE Field Monitoring Tests, Pg. 2 Only 01543X Mr. William W. Wilkins May 24, 1976 Page : 2 Shortly after enactment of the regulations on July 7, 1972, Onion Carbide Corporation and Montello, Inc. joined in carrying out a series of drillsite monitoring tests, in accordance with OSHA pre scribed methods. Locations were selected to be representative of a U drlllsi'.es. In fact, one of them was intentionally totally enclosed, in order to duplicate the worst possible conditions foreseeable. addition, dumping rates far in excess of those typical in actual practice were maintained, (as high as 3.000 pounds per hour, or six times the upper norm). The highest peak value of any test was 1.9 fibers per S CC? (less than one fift* of the regulated c e i ( l ^ s s hle-hest time weighted average measured was 0.4 fibers per cc, (less ? tenth of the current TWA regulation and less than one fourth of the .-.uch lower TWA planned for July 1, 1976). Subseqf.-nt field monitoring tests have continued to result in similar - reading'. A brief recap follows: _______ TEST LOCATION TEST SITE CEILING CONCENTRATION FIBERS/cc TIME-WEIGHTED AVERAGE FIBERS/cc Texas Panhandle Drilling Rig 1.0 0.4 0.5 0.3 1.9 0.4 C e n t -al Ok', ahorna Drilling Rig 0.4 0.3 Sout' Lou-stana Drilling Rig 1.4 0.3 0.6 0.3 Near Houston 1.8 0.4 Te as Drilling Rig 0.4 0.3 Canadian 1.8 0.4 Te as Drilling Rig 0.7 0.3 0.1 0.2 Vici O k *ahorna Drilling Rig 0.1 0.2 0.5 0.6 0.5 0.2 0.0