Characterizing submarine diesel exhaust particulate matter, elemental and total carbon concentrations during snorkeling operations

The International Agency for the Research of Cancer (IARC) classified Diesel Exhaust (DE) as a carcinogen due to a strong association between DE and lung cancer.  Exposure to elevated levels of DE is linked to acute adverse health effects such as asthma, headaches, irritation of the nasal passage, and nausea.  The primary objectives of this study was to characterize the occupational exposure to DE Particulate Matter (PM 10, 2.5,1 μm), Elemental Carbon (EC), and Total Carbon (TC) and to determine whether occupational exposure limits are exceeded during pier-side Snorkeling operations. A total of 27 air samples were collected on three LA Class Submarines, in nine sampling zones, over 4-hour periods in accordance with NIOSH Analytical Method 5040. Air samples were also collected using a direct reading aerosol monitor. EC concentrations were compared to ACGIH proposed threshold limit value (TLV) 20 μg/m3 as an 8-hr time weighted average (TWA). TC concentrations were compared to the Mining Safety and Health Administration (MSHA) permissible exposure limit (PEL) 160 μg/m3 as an 8-hr TWA. 100% of the area air samples collected outside the hull of the submarine within 50 feet of the Emergency Diesel Engine exhaust stack exceeded ACGIH TLV and MSHA PEL on Submarine 1.  Eighty-three percent (83%) of the air samples collected inside the hull of  Submarine 3 exceeded ACGIH TLV and MSHA PEL. Results of this study suggest that PM, EC and TC levels exceed recommended exposure limits while a Los Angeles Class submarine conducts snorkeling operations. Future studies should collect samples on Virginia and Ohio Class U.S. submarines using TC as a surrogate of exposure to diesel exhaust.