Safety Issues

Click here to open the PDF Chipper/Shredder Safety Guide published by the Occupational Safety and Health Administration,U.S. Department of Labor. (You will need Adobe Acrobat Reader installed to view file)

Portable wood or brush chippers are mechanical devices used to dispose of wood products such as tree trimming debris, rail road ties., logs, scrap lumber and other waste construction materials. Care must be taken in using these devices since the wood material is normally fed by hand through a loading chute into the cutting assembly. The cutting rotor operates at powerful high speed with a great amount of inertia.

It is essential that proper work practices be utilized to ensure that the wood chipping operation is undertaken in a safe manner. The following information is provided to you as a guideline for safe operation of this equipment.


The following safety equipment is mandatory for personnel working with wood chippers:

  1. Personal hearing protection
  2. CSA approved safety head ear.
  3. Full face shield, in addition to safety eye wear.
  4. Loose fitting leather gloves shall be worn by the person feeding the chipper.
  5. One-piece coveralls shall be worn (blaze color in areas where traffic may be present).
  6. Non-slip CSA approved safety footwear.


  1. Hands or feet shall not be placed beyond the curtain guard while the blade is in operation.
  2. A push stick or brush shall be used to force shorter or thorny brush into the chipper.
  3. Care shall be exercised when chipping dead or frozen wood in order to avoid kickback.
  4. Maximum diameter of material to be fed into the chipper shall be 150 mm (6 inches), unless manufacturer's specifications allow larger material size.
  5. Material from 75 mm to 150 mm (3 to 6 inches) diameter shall not exceed 2.5 metres (8 feet) in length, unless manufacturer's specifications allow longer material length.
  6. The person feeding the chipper shall stand to the side of the apron at the rear of material being fed into the machine.
  7. No person shall be allowed to stand or sit on any part of the discharge chute while the brush chipper is in operation.
  8. No person shall stand or sit on any part of the brush chipper while it is in operation or while it is being transported from one job site to another.
  9. The chipper apron is to be secured in the "up" position when being transported from one job site to another.


  1. Mechanical chippers must be maintained in accordance with the manufacturer's specifications:
    1. The motor ignition shall be locked out and the key removed from the ignition before any maintenance or service is performed, or when the chipper is left unattended.
    2. The chipper drum shall be blocked, and only authorized persons allowed to perform any service or maintenance.
    3. On the drum or blades, retightening of chipper blade bolts shall be done according to manufacturer's specifications.
  2. The chipper shall be equipped with a workable "kill" switch of approved design located at the in feed location.
  3. The chipper shall have a curtain in place at all times (workable in all weather conditions, in order to prevent fly-back of material.
  4. Before the wood chipper is started, the apron and feed platform should be checked and cleared of any foreign objects.
  5. The front of the feed apron table shall be a minimum of 1500 mm (6O inches) from the chipper blades.

Follow these suggestions to reduce the risk of personal injury:

  1. When purchasing or renting a chipper, evaluate it for safety of design and use. Are the belts, shafts, and cutting mechanisms covered? How are wood chips prevented from "kicking back" or "flying out" of the intake feed area? How is the chipped material discharged from the machine? When the machine becomes "jammed" how can it safely be cleaned out? Read consumer and other types of publications for evaluations of different makes of chippers on performance, safety, and maintenance. (3) Ask questions. The best time to consider machine safety is before you buy or rent it. Many machines are heavy and may be difficult to move and set up. If you are unable to follow the safety and operating procedures listed in the owner manual, or physically cannot handle the machine, don't buy one. It may be better to hire someone else to handle your yard wastes for you.

  2. Read, study, understand, and follow all safety procedures and use all safety equipment listed in the owner/operator manual for the chipper you are using. This should include all operation and maintenance procedures as well.

  3. Wear the proper clothing and protective gear when operating this kind of machinery. Clothing should include a long sleeve shirt and pants that are comfortable but not baggy or loose. Remove all jewelry or items of clothing that may become caught or tangled in the operating machinery.

    At a minimum, the protective gear package should include:
    a. Protective eyewear with side shields that meet or exceed American National Standards Institute (ANSI) standard Z87.1. Look for the ANSI label with this standard before you buy. Current prices range from $4.23 to $19.75.
    b. A hearing protector that is either the ear insert or the ear muff style. In either case you want the device to have an EPA Noise Reduction Rating (NRR) of 20db (loudness reduction) or more. The higher the rating the better. The current price range is from $8.99 to $29.75 for muff-style hearing protectors, and $0.27 to $11.95 for ear insert style hearing protectors, both single use and reusable types.
    c. Leather work boots, preferably with safety toes that meet ANSI standard Z41.1. Current prices range from $33.92 to $97.00 and up.
    d. Leather work gloves to provide hand protection from wood slivers and reduce skin abrasions. Current prices range from $2.11 to $9.99 and up.
    This "minimum level" four-piece protective gear package could be purchased for between $40.53 and $156.49 in Minnesota during March of 1990.4 If you are figuring the cost of a chipper, you need to include the cost of the personal protective gear that will allow you to operate it safely. Even if you are only renting a machine for a day or less you will need this type of protective gear for your own personal safety. Other optional gear might include a logger's safety helmet (a helmet with attached screen face shield and muff-style hearing protector attached into one unit), $27.99 to $49.00 and up; dust mask, $0.40 to $1.50; and chainsaw chaps, $47.99 to $67.50 and up. In every case you need to choose specific protective gear that fits you and that you are comfortable wearing. A piece of protective gear that is so uncomfortable that it is not used, cannot provide you with any protection!
  4. Keep children, observers, and pets well away from the area where you are operating the chipper.
  5. A chipping team of two people, working together, provides an added measure of safety and quicker access to help should an accident occur. The second person's primary job is to keep children and others away. This person needs to wear at least the minimum recommended protective gear.
  6. Put only approved materials into the machine at recommended feed rates. Materials such as metal or rocks can be accelerated to speeds in excess of 140 m.p.h. creating a danger for the operator and bystanders.
  7. Use of a written pre-start-up safety check list, and a post-shutdown safety check list can help to assure that you are following all of the necessary safety procedures.

Wood chipper shredders can be very dangerous, even fatal, if not used properly. You can search the web and find many accident reports of injuries and fatalities of people while using them. Getting fed through the chipper knives and being struck by the chipper disc hood are two of the most common causes of fatal injuries while using a wood chipper shredder. Even smaller home chipper units pose a grave threat to the careless user.

The following are recommendations for the safe use of wood chippers.

All safety devices and controls, such as emergency shut-off devices, should be tested and confirmed to be in proper working order before the wood chipper is used.

Read the operators manual and be trained on the proper and safe use of the wood chipper shredder.

Inspect the wood chipper each time before use. Check for defects such as broken or missing hood latches and pins or cracked and worn hinges. Replace any damaged or missing machine parts before use.

Before starting the wood chipper shredder make sure that the hood that covers the chipper knives is completely closed and latched.

Never work alone while using a wood chipper. Have someone else there with you at all times during operation.

Wear protective gear such as a hardhat, eye protection and hearing protection.

Wear close fitting, tucked in clothing when operating a wood chipper shredder. You should wear gloves that don't have cuffs, pants without cuffs and slip resistant footwear.

When you are ready to begin putting materials into the wood chipper run it at the lowest possible speed and have someone else listen for any noise that might indicate broken or loose parts. If an unusual noise is discovered DO NOT use the wood chipper. Have a professional check out and/or repair the wood chipper if necessary.

Keep your hands and feet out of the in-feed hopper.

Always feed brush and tree limbs butt end first into the hopper of a wood chipper.

Work from the side of the wood chipper shredder. This will allow you to have quick access to the emergency shutoff This will also minimize the risk of getting tangled in the branches.

Move away from the wood chipper once it has grabbed the material intended for shredding.

Lay the shorter materials on top of the longer materials or use a long branch to push the shorter material through the in-feed hopper.

Load leaves and small twigs directly into the wood chipper truck, not into the in-feed hopper.

Keep the area around the wood chipper shredder clear of any tripping hazards.

Make sure that all internal machine parts have come to a complete stop before opening the hood that is covering the chipper disc or drum of the wood chipper.