APPENDIX C Gas Hazard and Protection Against Gas
February 14, 1942
Salvage Bulletin #15
Subject: Hazard from Gas on Ships under Salvage-Protection Against
1. Lethal concentrations of gas have been found on the NEVADA, CALIFORNIA, and UTAH and fatalities have resulted on the first ship named. A very careful inspection, study and analysis has been made in the case of the NEVADA by Lieut.-Comdr. C. M. Parker, (M.C.) USN, who has submitted the following memorandum to the Salvage Officer:
The following observations were made on the U.S.S. NEVADA on the 7th of February, 1942 and subsequent days. They are quoted together with opinion for your consideration.
On boarding the ship the odor of Hydrogen Sulfide was detected and on going below decks concentration appeared to be heavier. On analysis the gas on the first three decks was in a range from 40 to about 100 parts per million.
In the trunk (where a disaster took place) at the level of the third deck a sample of the gas showed the following: Hydrogen Sulfide 400 parts per million, and a trace of Carbon Dioxide.
About the 10th of February a sample of air taken from the compartment forward opening into the trunk, below the third deck was taken and the analysis showed in excess of 1000 parts per million. At this time no carbon dioxide was found in any compartment of the ship.
Sampling with lead acetate paper as an indicator was continued. Only when the compartments were considered safe, were men allowed to go in them.
The method used to free spaces of Hydrogen Sulfide was: suction blowers as near water level as possible, which pulled the gas from the compartments and deposited it over the side within a few inches of the water. This method of ventilation is being continued.
The properties of Hydrogen Sulfide are relatively as follows: colorless, heavier than air, and at a low concentration it has the odor of a rotten egg, while at a high concentration it has a sweetish odor. However, at the higher concentration the nerves of smell in the nose are paralyzed rather quickly so that usually no odor is perceptible.
The maximum quantity of gas in the air considered safe for people to work in is 20 parts per million. The latest authorities state the concentration of 700 parts per million is sufficient to cause death in a short time, where as,
a concentration of 1000 parts per million may cause death instantaneously. Between these two concentrations varying effects may be noted, depending upon the concentration.
The symptoms are: irritation of the mucous membrane, of the eyes, nose, and the respiratory track, burning of the throat, and the general signs of a cold or a bronchitis, headaches and dizziness, gastro intestinal disturbances, easy fatigability, a slow pulse, irritability, certain physic disorders as temporary inability to concentrate, and that "all in" feeling.
My conclusions at the early point in the study make it seem advisable to take the following precautions. Men going into a ship with water in the compartments for the purpose of opening hatches, and other necessary work in conjunction with salvage should only enter with oxygen rescue apparatus or a face plate receiving its air from outside the ship. Divers of course are well protected. After these compartments are freed of water, suction ventilation should be instituted. Tests then must be made, before men are allowed to enter these compartments. This process must be continued for each compartment, on each deck. Tests should be supervised by someone familiar with this gas and possibly other gases is advised.
2. On 13 February 1942, COMTRAINRON SIX arranged for Lieut.Comdr. Parker to give a lecture on this subject to as many of the officers attached to Ships in Ordinary as could be spared. This lecture was of great interest and caused everyone present to appreciate the seriousness of the hazard which is certain to be encountered on all ships where salvage operations are being conducted. It was decided that the Ship Superintendent of each ship would be responsible for seeing that proper procedure and protection is carried out in connection with the gas hazard, and that he would cooperate closely with the personnel to be trained to make tests, etc., by Lieut. Comdr. Parker.
3. All officers of the Salvage Division are being furnished a copy of this Bulletin and are instructed to take special care with respect to the gas hazard as discussed in Dr. Parker's memorandum. They will take such steps as are necessary to assure themselves that they send no men unprotected into compartments except those known to be safe. The nature of the hazard and the precautions to be taken should be made clear to all civilian workers who are assisting with salvage operations, whether they be Navy Yard workmen or Contractor's men.
4. Arrangements are being made for Dr. Parker to lecture to officers of the Salvage Division at an early date.
All Salv. Off.
H. N. WALLIN
Captain, U.S. Navy