www.osha.gov/farmsafety • (800) 321-OSHA (6742)

Working Safely Around 

Manure Storage Structures 

A common function of farm operations is the storage and distribution of liquid and 

solid manure. Manure storage structures (also referred to as waste storage facilities) 

can expose farm workers to toxic gas, oxygen deficient atmosphere, fire, explosion, 

mechanical, and drowning hazards. 

These hazards may severely injure or kill farmworkers as well as their would-be rescuers. Proper structure identification, worker 

training, and implementation of a safety and health program that includes an emergency action plan is the first step to keeping 

workers and their families safe around manure ponds, lagoons, tanks, and pits.

Types and Characteristics

Manure storage structures are common on farms with livestock operations. Storage structures may vary based on the animal, 

geographic location of the farm, use of the manure, and physical consistency of the manure. Three primary types of manure 

storage structures and their typical characteristics are summarized below. The safe work practices, in the following section, apply 

to any type of manure storage structure.

Manure Pond/Lagoon Manure Tank Manure Pit

Location Outdoors Above or below ground Indoors underneath livestock house

Ceiling Uncovered Enclosed or open Enclosed. Ceiling is often slatted/

slotted floor for livestock

Walls and bottoms Lined with water-resistant materials Pre-fabricated vertical side walls 

and impervious floor Lined with water-resistant materials

Permanent 

Ladders No Yes, inside and outside Yes, inside

Ventilation System No No Yes

Permit-required 

Confined Space No Could be Could be

Other 

Characteristics

Often surrounded by grassy surface 

and bordered by four-foot fence 

with secure gate

Limited means of entry or exit Attached pump-out pit

Crust-like surfaces that trap gases can form on top of liquid manure during extended dry or cold periods, 

especially for open/uncovered structures.
Safe Work Practices

General/Management Agitation, Pumping, and Removal Fire/Explosion Confined Space Access Emergency and Rescue

Manure safety is critical, regardless of 

where and how the manure is stored. 

To stay safe:

• Limit access to authorized 

personnel, and never work alone.

• Inspect periodically to ensure 

that storage structures never leak 

or overflow.

• Inspect manure structure ventilation 

system regularly and prior to entry.

• Keep access ladders in good repair 

and free from obstruction and 

debris to reduce slipping.

• Install barriers on piers and push-off 

platforms to prevent vehicles from 

falling into ponds and lagoons.

• Provide guardrails or metal grill 

covers for all trap doors, floor holes, 

and wall openings.

• Guard manure augers, chains and 

sprockets, belts/pulleys, cables/

pulleys, and manure scrapers 

to prevent worker contact or 

entanglement.

• Follow lockout/tag out procedures

for machinery, and shut off and 

remove agitation and pumping 

equipment before performing 

services or repair activities. 

• Use lights at night.

• Use extra caution during hot weather 

as dangerous gases may increase.

Agitation, pumping, and removal often 

release trapped toxic gases, such as 

hydrogen sulfide, methane, ammonia, 

and carbon dioxide. These gases can 

expose workers to asphyxiation, fire, and 

explosion hazards. To stay safe:

• Measure and monitor atmospheric 

conditions and know the warning 

signs of toxic gas exposure.

• Train workers to stay at a safe 

distance, as built-up gases can 

quickly overcome them if a crustlike surface opens.

• Remove workers and livestock from 

manure pits or buildings before 

agitation; allow gas to dissipate 

and test atmosphere using 

remote means before entering the 

structure. 

• Agitate ponds and lagoons during 

windy conditions to allow gases 

to dissipate properly; assess wind 

direction and stay upwind.

• Operate fans during agitation and 

pumping to maximize ventilation.

• Wear a multi-gas monitor when 

performing agitation, pumping, 

or removal.

Sparks from barn heaters, electrical 

equipment, or welding (“hot work”) can 

cause fire or explosion. To stay safe:

• Identify ignition sources that may 

cause fire or explosion.

• Use intrinsically safe or explosionproof ventilation equipment.

• Prohibit smoking or the use of 

open flames.

• Keep an ABC-type fire extinguisher 

near each exit and train workers 

to use them; otherwise, train 

workers to leave the area and 

contact first responders.

• Establish a permit system to control 

and monitor welding, brazing, or 

torch cutting.

• Complete a Job Hazard Analysis (JHA) 

and have each employee review it 

before conducting hot work. 

• Ventilate and test atmosphere 

before, during, and after hot work.

• Cover manure pit slatted floors 

with flame-resistant tarps when 

performing hot work.

Hazards typically arise during the 

repair and cleaning of tanks or pits. 

The most common hazard is hazardous 

atmosphere (toxic gases). To stay safe:

• Develop and maintain a written 

confined space entry program 

where workers enter permitrequired confined spaces.

• Post warning signs in the language 

of the worker at permit-required 

confined space entries.

• Never work alone. Have another 

person remain outside the tank 

or pit and maintain visual or 

verbal contact.

• Use powered ventilation systems 

suitable for use in a flammable 

environment to maintain safe air 

quality inside the tank or pit.

• Use a portable multi-gas detector in 

the tank or pit to test atmosphere 

before entering; wear a multigas monitor while working in the 

confined space.

• Train workers on how to use and 

maintain respiratory protection and 

other protective equipment.

• Wear a body harness and lifeline 

attached to a tripod and a winch for 

easy retrieval when working inside 

a tank.

Immediate response is critical for 

saving an incapacitated worker in a 

manure storage structure. Would-be 

rescuers may become victims 

themselves. To stay safe:

• Develop and maintain an emergency 

action plan.

• Review the emergency action plan 

with workers and perform drills; 

know emergency response time.

• Provide a working phone and post 

emergency contact numbers within 

50 feet of a manure storage structure.

• Keep designated escape paths free 

of obstructions.

• Train in rescue operations; keep a 

rescue pole, rope, and other lifesaving 

equipment near ponds and lagoons 

to allow for non-entry rescues.

• Never attempt a rescue unless 

trained and wearing proper 

respiratory protection, such as a 

supplied air system or self-contained 

breathing apparatus.

• Rescuers must be physically capable 

of using a tripod retrieval system for 

confined space rescues.

Leave the space immediately and seek help, if you experience:

irritated eyes, nose, or throat • headache • dizziness • drowsiness • confusion • nausea or vomiting • rapid or difficulty breathing • increased heart rate

www.osha.gov

(800) 321-OSHA (6742) OSHA 4166-11 2021