entered a declared safe space, periodic tests are made to
determine that it is still safe. Upon the detection of an
unsafe condition, an order must be given for all
personnel to evacuate the space.
Because a space cannot be guaranteed to remain
safe, you should be aware of the symptoms of bad air.
Symptoms of bad air include the following:
Excessive fatigue from slight exertion
If you feel any of these symptoms, warn others and get
to fresh air immediately.
A more dangerous situation exists if a compartment
has no, or very little, oxygen. If this happens, a person
can lose consciousness almost immediately without
warning. If such an incident occurs while you are in an
area, do not enter the space without wearing an OBA or
air-line mask; otherwise, you will become a casualty.
Always summon (call for) help before making a rescue
attempt. Also, have a person stationed at the entrance to
maintain communications while watching to see that
you are not overcome.
TYPES OF SOLVENTS
As you have already learned, the Navy uses many
types of solvents for many cleaning assignments. You
also know that many of these solvents are highly toxic
and some are highly flammable. Take special care when
using many of these solvents; make sure you store them
in cool, dry areas. Material Safety Data Sheets
(MSDSs) list the storage requirements for solvents. You
should refer to the MSDS for solvents you are using.
Most cleaning solvents contain toxic substances.
These substances can cause injuries if they are inhaled,
absorbed by the skin, or ingested. All toxic materials
must be handled carefully to prevent injury. Many of
them have additional hazards, such as flammability. The
following paragraphs contain information about
general categories of toxic cleaning solvents. If you
have any questions about the solvent you are going to
use, check the Maintenance Requirement Cards
(MRCs) for the task or ask your supervisor.
The three types of solvents covered in this section
are chlorinated cleaning solvents, organic cleaning
solvents, and fluorocarbon refrigerants and solvents.
Chlorinated Cleaning Solvents
Chlorinated cleaning solvents can be highly toxic if
used improperly. They may be irritating to skin and
toxic if ingested. In confined spaces, in spaces with
inadequate ventilation, or when the vapor concentration
is increased by heating, toxic vapors may cause damage
to the lungs, eyes, and nervous system. Solvents
decompose at high temperatures and produce gases
more toxic than the solvents themselves. Solvents react
with alkalies, oxidizers, and powdered metals to
produce toxic gases.
Common types of chlorinated cleaning solvents are
trichloroethane (inhibited methyl chloroform),
trichloroethylene, tetrachloroethane, and tetra-
chloroethylene (perchloroethylene, dry-cleaning
solvent). Because of the extreme dangers involved, the
Navy severely restricts the use of these solvents.
You should observe the following precautions when
working with chlorinated cleaning solvents:
Never stow chlorinated cleaning solvents near
heat sources or open flames.
Dont allow them to come in contact with hot
Make sure stowage areas are well ventilated and
monitored regularly by the gas free engineer.
Dont stow these solvents near incompatible
materials. (NOTE: Incompatible materials
include strong alkalies, such as sodium
h y d r o x i d e ; o x i d i z e r s , s u c h a s c a l c i u m
hypochlorite and sodium nitrate; or powdered
metals, such as aluminum.)
When handling chlorinated cleaning solvents, wear
the following personal protective equipment (PPE):