Sodium Hydrosulfide (Nahs) : Recommended Procedures For Truck Unloading

Sodium Hydrosulfide (NaHS)
Recommended Procedures
for Truck Unloading
TDC, LLC 1916 Farmerville Hwy. Ruston LA 71270

The following presentation was designed
to provide specific information on
unloading trucks containing Sodium
Hydrosulfide (NaHS). This presentation
has been developed as a guide only.
THINK SAFETY AT ALL TIMES!
STAY ON TOP OF SAFE HANDLING PROCEDURES

Safety is Everyone’s Business
Training Requirements
Personnel handling hazardous chemicals should be

trained in accordance with the applicable federal
and state requirements These training
requirements include, but may not be limited to:
• Hazard Communications - 29 CFR 1910.1200

• Personal Protective Equipment - 29 CFR 1910.132
• Respiratory Protection - 29 CFR 1910.134
• Occupational Noise Exposure - 29 CFR 1910.95
• Hazmat - 49 CFR 172.700
Shipping Requirements
Sodium Hydrosulfide (NaHS) is classified

as a corrosive and toxic liquid. The Proper
Shipping Description is:
UN2922 Corrosive liquids, toxic, n.o.s., 8(6.1),
PG II (sodium hydrosulfide solution)
Bulk shipments are

placarded “Corrosive”.
KNOW THE
PRODUCT!
Read the MSDS

MSDS Review
¾ Sodium Hydrosulfide (NaHS) is very alkaline (pH 11.5-
12.5) and very corrosive to the skin.
¾ Solution is typically yellow to dark green with a strong

hydrogen sulfide (rotten egg) odor.
¾ Solutions are 20% to 45% strength and weigh 9.6 –

10.9 ppg.
¾ The vapor space over NaHS solutions contains highly

toxic hydrogen sulfide (H2S). This gas is colorless and
heavier than air. The level of H2S above the solution is
increased by solution contact with acidic materials,
heating the solution and dilution, which lowers the pH of
the solution.
NaHS is manufactured by reacting Hydrogen
Sulfide Gas (H2S) with Sodium Hydroxide
(Caustic Soda) (NaOH).
H2S + NaOH = NaHS + H2O

Hydrogen Sulfide Gas + Caustic Soda = Sodium Hydrosulfide + Water
Procedure
Employers should consult with their

safety personnel and terminal operators
when developing a detailed written NaHS
unloading procedure for their specific
location.
Step 1: Wear the required PPE.
• Hard Hat
• Chemical Goggles
• Full Face Shield
• Chemical Suit
• Chemical Protective Gloves
• Chemical Protective Boots
• Breathing Air/ SCBA (When
opening vapor space)
Step 2: Inspect the unloading area and
stage the truck.
Step 3: Chock the wheels.
Step 4: Place the orange traffic cone.
Step 5: Attach grounding cable.
Step 6: Check for possible hazards.
Step 7: Connect vapor recovery system.
Step 8: Connect unloading hose.
Step 9: Product Sampling, if required.
Step 10: Set the valves for transfer of
product to storage.
Step 11: Begin transfer of product.
Step 12: Complete liquid transfer and stop
the off-loading process.
Step 13: Disconnect the unloading hose.
Step 14: Disconnect the vapor
recovery system.
Step 15: Remove the grounding cable.
Step 16: Remove the wheel chocks and
store in a safe location.
Step 17: Check for hazards.
Step 18: Remove the traffic cone and
instruct driver on exiting.
Step 19: Clean the unloading area if required
Step 20:
Remove and clean
the PPE.
Spills and Cleanup
Small Releases
• Confine and absorb small releases with

sand, earth or other inert absorbent.
• Oxidize the residual reactive sulfides with a
weak (3-5%) hydrogen peroxide solution.
Note: Normal drug store hydrogen peroxide
is 3%.
• If unavailable, diluted common household
bleach may be substituted. Diluted peroxide
and bleach minimize the potential for the
release of H2S vapors.
Large Releases
• Wear proper protective equipment.

• Confine area to qualified personnel.
• Shut off release if safe to do so.
• Dike spill area to prevent runoff into sewers,
drains or surface waterways.
• Recover as much of the solution as possible.
• Treat remaining material as a small release.
Hydrogen Peroxide
• Commercially purchased 35% Hydrogen Peroxide

must be diluted to 3–5% before it can be used to
oxidize small spills.
• Do not attempt to oxidize a NaHS spill with 35%
Hydrogen Peroxide.
• Review the 35% Hydrogen Peroxide label and MSDS

before handling and diluting and wear the required
Personal Protective Equipment (PPE).
Diluting 35% Hydrogen Peroxide to a 3-5% Solution
1. Add approximately one-half (1/2) gallon or 1.89 liters of 35%
peroxide to a clean/dry, appropriately labeled 5-gallon bucket.
2. Add approximately 4 and one-half (4 ½) gallons or 17.03 liters
of water to the bucket. Wear the required PPE.
Apply the diluted Hydrogen Peroxide
solution to the small NaHS spill. Always
wear the required Personal Protective
Equipment (PPE).
Hard Hat
Chemical Goggles
and Face Shield
Protective Gloves
Rain Suit/Slicker
Protective Boots
REMEMBER ! ! ! !
• NEVER rinse a NaHS spill into a storm

drain or sewer.
• Potential toxic and explosive mixtures of
hydrogen sulfide gas can be created
when NaHS comes in contact with acids.
Emergencies
Drip buckets and containment pads can be
utilized for catching small spills and leaks.
Note: Drip buckets should be labeled to ensure

NaHS is not mixed with other chemicals.
Ensure emergency showers and eyewashes
are available and tested prior to each
unloading operation.
If Sodium Hydrosulfide comes in contact
with your eyes:
• Immediately flush with large quantities
of water for at least 15 minutes.
• Hold your eyelids apart during the
irrigation to insure a thorough flushing
of the entire area of the eye.
• Obtain immediate medical attention.
MAN DOWN !
In the event you find a coworker

unconscious at the worksite and
you suspect H2S vapors are present
DO NOT attempt a rescue until you have:
1. Notified other personnel, and
2. Donned breathing air (SCBA).
3. Always use the buddy system
FIRE !
•Sodium Hydrosulfide Solution is non-

flammable.
• If exposed to heat or acids, H2S will be released
and may form explosive mixtures with the air.
•If the railcar is exposed to fire, cool it with a water
spray.
•Remember heating may cause the release of
Hydrogen Sulfide vapors.
When handling, transporting, storing or
distributing any hazardous chemical, please
consult the manufacturer’s Material Safety Data
Sheet (MSDS).
Should you have any questions regarding this

presentation or would like additional
information on Sodium Hydrosulfide related
issues, please contact
TDC, LLC at (800) 422-6274.
The information and recommendations contained in this presentation have been compiled from reliable
sources, TDC, LLC makes no guarantee as to, and assumes no responsibility for, the correctness,
sufficiency or completeness of such information or recommendations. Other or additional safety measures
may be required based on your particular circumstances.

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Sodium Hydrosulfide (NaHS)

TDC, LLC 1916 Farmerville Hwy. Ruston LA 71270

STAY ON TOP OF SAFE HANDLING PROCEDURES

Personnel handling hazardous chemicals should be

• Hazard Communications - 29 CFR 1910.1200

Sodium Hydrosulfide (NaHS) is classified

Bulk shipments are

Read the MSDS

¾ Solution is typically yellow to dark green with a strong

¾ Solutions are 20% to 45% strength and weigh 9.6 –

¾ The vapor space over NaHS solutions contains highly

H2S + NaOH = NaHS + H2O

Employers should consult with their

• Confine and absorb small releases with

• Wear proper protective equipment.

• Commercially purchased 35% Hydrogen Peroxide

• Review the 35% Hydrogen Peroxide label and MSDS

• NEVER rinse a NaHS spill into a storm

Note: Drip buckets should be labeled to ensure

In the event you find a coworker

•Sodium Hydrosulfide Solution is non-

Should you have any questions regarding this

TDC, LLC at (800) 422-6274.

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