UPDATE ON QUESTION OF MASK PERFORMANCE IN H2S ENVIRONMENT

File: 120396_oct96_decls22_0001.txt
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Subject: UPDATE ON QUESTION OF MASK PERFORMANCE IN H2S ENVIRONMENT       

Unit: US NAVY     

Parent Organization: US NAVY     

Box ID: BX300104

Folder Title: NAVSEA INFORMATION PAPER CNA 2898                                                               

Document Number:          2

Folder SEQ  #:         43



                UPDATE ON QUESTION OF MASK PERFORMANCE IN H2S ENVIROMMS
                                       'UNCLASSIFIED
                1. Information obtained from the Armyts Chemical Research,
                Development and Engineering Center (CRDEC),, indicates that carbon
                can take up to 10% of its weight of H2S (a vezy high capacity).
                A conservative estimate for H2S break-through times is:

                                200 ppm
                                500 ppm
                               1000 ppm             5 U.S.C. 552 (b)(1)

                2. NRL provided the following handbook information on the hazard
                of varying concentrations of hydrogen sulfide in air:

                     Concentration (ppm)                     Response

                        10                   Threshold Limit Value (TLV) for
                                               prolonged exposure
                        70-150               Slight symptoms after several hours
                                               exposure
                        170-300              Maximum concentrations for I hour
                                               without serious effects
                        400-700              Dangerous after exposure of 0.5-1
                                               hour
                        700 and  above       Fatal in 30 minutes

                "In concentrations of 20 to  150 ppm,, hydrogen sulfide irritates
                the eyes. Slightly higher concentrations irritate the upper
                respiratory tract and, if prolonged may result in pulmonary
                edema. Inhalation of 500 ppm for 30 minutes produces headache,
                dizziness, excitement, staggering and gastroenteric disorders,
                followed in some cases by bronchitis or bronchial pneumonia.
                Concentrations above 600 ppm can be fatal within 30 minutes
                through respiratory paralysis."

   3. The human nose can detect H2S concentrations in the 10-50 ppb
                (parts per billion) range. Since this is far below the TLV for
                prolonged exposure (10 ppm),, the nose is a good and safe
                indicator of the need to replace mask canisters. However, this
                indication does not last long,, since the nose becomes desensi-
                tized to H2S rather quickly. (This also means that if exposed
                and desensitized to H2S before donning the mask, breakthrough
                will not be detected).

                4. There is an added concern when operating in a fresh oil
                spill, particularly near the source. -Evaporation from light
                crude, such as Kuwaiti crude,.could lead to high concentrations
                of organic (hydrocarbon) vapors in the air. If the mask is worn
                to protect against H2S,, these hydrocarbons will be adsorbed on
                the charcoal$ thereby reducing the capacity for H2S and chemical
                warfare agents. we are pursuing this issue.
   0            5. RAVSEA point of contact is Mr. Pete Jung
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                                DECLASSIFIED
                                ON: 04 NOV 96                           28761
                                BY: DON GWDP IAW OPNAVINST 5513. SERIES

Document 1 f:/Week-41/BX300104/NAVSEA INFORMATION PAPER CNA 2898/update on question of mask performance in h2s en:1122961646535
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File Room = oct96_declassified
File Cabinet = Week-41
Box ID = BX300104
Unit = US NAVY
Parent Organization = US NAVY
Folder Title = NAVSEA INFORMATION PAPER CNA 2898
Folder Seq # = 43
Subject = UPDATE ON QUESTION OF MASK PERFORMANCE IN H2S EN
Document Seq # = 2
Document Date =
Scan Date =
Queued for Declassification = 01-JAN-1980
Short Term Referral = 01-JAN-1980
Long Term Referral = 01-JAN-1980
Permanent Referral = 01-JAN-1980
Non-Health Related Document = 01-JAN-1980
Declassified = 22-NOV-1996