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Two individuals overcome by hydrogen sulfide gas while cleaning a farm facility water well with 28% liquid muriatic acid.

Michigan State University
Morgantown, WV: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, FACE 01MI061 & FACE 01MI063, 2002 Apr; :1-6
On August 15, 2001, two males, an Amish farmer, 42 years old, and a friend, 60 years old, died from inhalation of hydrogen sulfide gas while cleaning the well screen of a driven point well with 28% uninhibited liquid muriatic acid. (An inhibited acid contains organic additives that protect the metal surface from the action of the acid). The well was approximately 300 ft. from the road, was approximately 150 ft. west of the residence, and was 20-25 ft. downhill from the livestock barn. A 5 ft. x 5 ft. wood shed was built around the well for protection. The shed was approximately 8 ft. tall, had a 30 in. door facing east, had 2 in. x 4 in. studs and had particleboard walls with batt insulation. There were no windows in the shed. The well pit had concrete walls. The pit was approximately 4-1/2 ft. deep, was 4 ft. x 4 ft. wide, and had a 2 in. x 8 in. wood plank across the pit opening. At the base of the pit, there was a driven point well with a 2-in. steel pipe and a jet pump. The emergency responders found an empty 64-ounce container of muriatic acid, a 1/4 full 64-ounce container of muriatic acid, funnel and 1/2 in. white polypropylene plastic tubing nearby. The funnel was outside of the well's protective structure; the tubing was inside of the well. The well casing was open. The well was running "slow" and the owner thought the problem could be a plugged well screen. The farmer used liquid muriatic acid to clean the screen. The event was unwitnessed, so the actual sequence of events is unknown. There appears to have been a reaction when the muriatic acid was added to the well water, resulting in a hydrogen sulfide emission from the well. A family member of the victim detected the muriatic acid odor and went to investigate. The family member noticed the individuals and went to the house to call emergency personnel. When the emergency responders arrived, the individuals were found in the well pit in approximately 4 in. of water/muriatic acid. Upon arrival at the scene, emergency personnel could detect a muriatic acid odor from the road. One of the individuals succumbed to hydrogen sulfide fumes and died at the scene; the other individual was transported to a local hospital, where he later died. Recommendations: 1. Private water well owners should not use uninhibited liquid muriatic acid to clean well screens; owners should explore acid alternatives that are in granular or palletized form, slower dissolving, produce less hazardous fumes and are more environmentally friendly. 2. Well owners should consider well location, well construction, and well management and maintenance issues so the well and water quality are protected from outside contamination sources.
Accident-analysis; Accident-potential; Accident-prevention; Accidents; Injuries; Injury-prevention; Safety-education; Safety-equipment; Safety-practices; Safety-measures; Traumatic-injuries; Region-5; Work-practices; Work-analysis; Work-areas; Work-environment; Work-performance; Acid-gases; Acids; Chemical-properties; Chemical-reactions; Farmers; Agricultural-workers
Publication Date
Document Type
Field Studies; Fatality Assessment and Control Evaluation
Funding Type
Cooperative Agreement
Fiscal Year
NTIS Accession No.
NTIS Price
Identifying No.
FACE-01MI061; FACE-01MI063; Cooperative-Agreement-Number-U60-CCU-521205
SIC Code
Source Name
National Institute for Occupational Safety and Health
Performing Organization
Michigan State University
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division