Manure Pit Hazards

Farm Safety & Health Digest Vol. 3, No. 4, p. 3

Manure Pit Hazards is one of the chapters from Lessons in Farm Safety, an interactive curriculum used to teach children about farm safety. Lessons in Farm Safety was developed by the Farm Safety & Health Program team at the University of Minnesota.

Farm workers risk their lives every time they enter a manure pit. The oxygen-deficient, toxic, and /or explosive atmosphere which can develop in a manure pit has claimed 12 lives in Minnesota since 1994. Unfortunately, this is not just an "adult" problem; three of the twelve fatalities in Minnesota were of children under six years of age. This lesson reviews the reasons farmers use manure pits, common and dangerous gases found in manure pits, and how a person can be safe when working in and around manure pits.

By the end of this lesson the learner will:

  • Recognize the specific hazards associated with manure pits.
  • Describe and name the four gases found in the highest concentration in manure pits.
  • Correctly state the procedure to follow if someone has fallen into a manure pit.
  • Identify proper protective equipment to use when entering a manure pit.

Tell students the purpose of manure pits. Manure pit systems, used primarily on swine and dairy farms, allow for the easy cleaning of animal confinement buildings and efficient underground storage of large amounts of raw manure. Because the dangerous pit gases may not always be present, farm workers may have successfully entered these pits in the past.

Invite a respiratory therapist to speak to the group about how the lungs function and the symptoms of respiratory disease. Good visual aids include respiratory protection devices, Use Manure Pit slide set (see resources) or review the properties of gases that may be found in manure pits.

Set up manure pit display (directions follow). Demonstrate displacement of oxygen by toxic gases by lighting match and slowly lowering it into the tank (wrap a coated wire bread twisty around the match to lower it through the slats). The flame will quit burning within a few inches, well above the visible layer of gas. If you allow a few minutes for the gases to accumulate the flame will burn out just beneath the slatted floor. This will reinforce the concept that gas s necessary to breath (or allow a flame to burn) are invisible and can fill a manure pit. Be sure to emphasize that a person should NEVER enter a manure pit with a lit match.

Search the internet for manure pit web sites. A good place to start might be the University of Minnesota's manure education and research page.

You will need one of each of the following items: 2½ gallon aquarium; toy cow, pig, and bull (1/32 scale); one pound of dry composted manure or dark soil; screen trim (any other thin wood will also work); gray spray paint; glue; Manure Pit posters (see resources); water; matches; and dry ice (pellets, not blocks); gloves to handle dry ice; and chocolate stars or kisses to simulate manure on top of floor (optional).

WARNING! : Dry ice is extremely cold and may cause severe burns in contact with skin. It also liberates heavy gas which may cause suffocation. Do not enter confined areas where dry ice is used or stored until adequately ventilated. Do not taste. Do not put in stoppered glass jars or other sealed containers. Handle with gloves. Keep out of children's reach.
Photo of Pigs
WHAT ARE MANURE PITS AND WHY ARE THEY DANGEROUS? (PowerPoint slide set) Description: Interactive slide set that can be made into any size posters from a disk or used with a slide projector. Covers reasons for using manure pits, common gases present in pits, reasons some Minnesota farmers have entered pits (and died), correct way to enter pit, and what to do if someone has fallen into a pit.

PC compatible disk in .ppt format available for $3.00. You will need to have Microsoft PowerPoint software on your computer to use the disk. Photographic slides available for $15.00. Order from: Farm Safety and Health Program, Biosystems & Agricultural Engineering Department, University of Minnesota, 1390 Eckles Ave., St. Paul, MN 55108-6005. Make check payable to the University of Minnesota. An alternative method of viewing the PowerPoint slides is to go directly to the slides:

The Poop About Manure

For more information, e-mail us at the Farm Safety & Health Program

Want to know more about manure? Check the Minnesota Extension Manure Page!

Go to the Farm Safety & Health in Minnesota Web page

Disclaimer and Reproduction Information: Information in NASD does not represent NIOSH policy. Information included in NASD appears by permission of the author and/or copyright holder. More