Phosphate ester fluid conforming to specifi-
cation MIL-H-19457 is used in aircraft elevators,
ballast valve operating systems, and replenish-
ment-at-sea systems. This type of fluid contains
a controlled amount of neurotoxic material.
Because of the neurotoxic effects that can result
from ingestion, skin absorption, or inhalation of
these fluids, be sure to use the following
1. Avoid contact with the fluids by wearing
2. Use chemical goggles or face shields to
protect your eyes.
3. If you are expected to work in an
atmosphere containing a fine mist or spray,
wear a continuous-flow airline respirator.
4. Thoroughly clean skin areas contaminated
by this fluid with soap and water.
5. If you get any fluid in your eyes, flush them
with running water for at least 15 minutes
and seek medical attention.
If you come in contact with MIL-H-19457
fluid, report the contact when you seek medical
aid and whenever you have a routine medical
Naval Ships Technical Manual, chapter 262,
contains a list of protective clothing, along with
national stock numbers (NSN), for use with fluids
conforming to MIL-H-19457. It also contains
procedures for repair work and for low-level
leakage and massive spills cleanup.
PHOSPHATE ESTER FLUID DISPOSAL.
Waste MIL-H-19457 fluids and refuse (rags and
other materials) must not be dumped at sea. Fluid
should be placed in bung-type drums. Rags and
other materials should be placed in open top
drums for shore disposal. These drums should be
marked with a warning label stating their content,
safety precautions, and disposal instructions.
Detailed instructions for phosphate ester fluids
disposal can be found in Naval Ships Technical
Manual, chapter 262, and OPNAVINST 5090.1.
Silicone Synthetic Fire-Resistant Fluids
Silicone synthetic fire-resistant fluids are
frequently used for hydraulic systems which
require fire resistance, but which have only
marginal requirements for other chemical or
physical properties common to hydraulic fluids.
Silicone fluids do not have the detrimental
characteristics of phosphate ester fluids, nor
do they provide the corrosion protection and
lubrication of phosphate ester fluids, but they are
excellent for fire protection. Silicone fluid
conforming to MIL-S-81087 is used in the missile
holddown and lockout system aboard submarines.
Lightweight Synthetic Fire-Resistant Fluids
In applications where weight is critical,
lightweight synthetic fluid is used in hydraulic
systems. MIL-H-83282 is a synthetic, fire-resistant
hydraulic fluid used in military aircraft and
hydrofoils where the requirement to minimize
weight dictates the use of a low-viscosity fluid.
It is also the most commonly used fluid in aviation
support equipment. NAVAIR 01-1A-17 contains
additional information on fluids conforming to
The most widely used water-based hydraulic
fluids may be classified as water-glycol mixtures
and water-synthetic base mixtures. The water-
glycol mixture contains additives to protect it from
oxidation, corrosion, and biological growth and
to enhance its load-carrying capacity.
Fire resistance of the water mixture fluids
depends on the vaporization and smothering
effect of steam generated from the water. The
water in water-based fluids is constantly being
driven off while the system is operating. There-
fore, frequent checks to maintain the correct ratio
of water are important.
The water-based fluid used in catapult
retracting engines, jet blast deflectors, and
weapons elevators and handling systems conforms
The safety precautions outlined for phosphate
ester fluid and the disposal of phosphate ester
fluid also apply to water-based fluid conforming
Hydraulic fluid contamination may be
described as any foreign material or substance
whose presence in the fluid is capable of adversely
affecting system performance or reliability. It may
assume many different forms, including liquids,
gases, and solid matter of various composition,
sizes, and shapes. Solid matter is the type most
often found in hydraulic systems and is generally