Manure collection tank at Beltsville (Maryland) Agricultural Research Center.
I recently received a call from Washington DC and an investigator from the Occupational Safety and Health Administration (OSHA) was on the line. Since OSHA does not routinely deal with agriculture I braced myself to hear what the call subject would be. The call was prompted by the unfortunate death of a farm worker who was standing on top of a liquid manure spreader tank as it was filling up. The cause of death was asphyxiation associated with hydrogen sulfide gas. The representative was hoping to understand what normal manure handling equipment and practices are since she had not run into this type of accident in the past.
Considering the amount of time producers and professional manure handlers spend working with manure these incidents can be viewed as relatively infrequent occurrences. However, in working with the manure handling industry I have come to realize that many instances of loss of consciousness or livestock loss go unreported. In the Mid-Atlantic region the past couple years have been thankfully quiet as far as headlines of manure handling deaths go. Perhaps, this could be attributed to greater industry awareness and education after several well-publicized tragedies in 2011-2012. Other regions were not so fortunate. In 2015, two pairs of co-working father and sons died when trying to remove or retrieve equipment from manure storage areas. One instance was in Wisconsin and the other in Iowa.
Similar situations occur worldwide. A recent article in the Journal of Agromedicine (Park, et.al. January 2016) reviewed incidents from 1998 to 2013 that involved gas exposure during manure handling at swine facilities in Korea. Thirty workers died from hydrogen sulfide asphyxiation in 17 incidents. Of the thirty deaths, 10 were handling manure, 8 were performing maintenance and 12 were attempting to perform rescue without proper equipment.
An earlier article in the same journal (Beaver & Field, 2007), Purdue University researchers studied 91 deaths (7 from Pennsylvania) and 21 severe injuries related to manure-generated gas from 1974 to 2004. The researchers reported that with 34% of the deaths exposure occurred during repair or maintenance and 22% of deaths occurred to those attempting rescue. Disturbingly, 21% of the fatalities investigated in this study occurred to people under the age of 16. Witnesses listed thirteen of the victims as 'playing and discovered missing'. All of these were children.
Reoccurring themes are easily found in reports on this subject. I hope you can learn from these items that jump out at me:
- Hydrogen sulfide is our most dangerous gas and can cause immediate asphyxiation at high levels. Some of today's economic imports to the farm, such as distiller's grains or gypsum bedding, actually increase sulfur levels in manure. Microbial degradation of sulfur compounds in storage leaves hydrogen sulfide as a by-product.
- Repair and equipment retrieval is dangerous. It is tempting to enter a confined area for a quick job. Do not do that. Remove equipment for maintenance and retrieve dropped items with a magnet or hook.
- Rescuers are at risk. Rescuers often end up as victims. The recommendation of course it to never go in to try to retrieve someone without proper rescue equipment. That's easy to say, but perhaps harder to adhere to when a family member or co-worker is in trouble. In this situation it is better to be an unsung hero by operating in a manner that minimizes risk and avoids these situations in the first place. Don't become a statistic.
- Liquid manures are more dangerous than solid manures. Nonetheless, solid manure systems need respect. I know two local men who have lost consciousness while moving poultry broiler litter.
- It is unclear if dairy or swine farms present higher risk. The Field and Beaver report found that 55% of fatalities occurred in the diary industry and 44% in the swine industry.
- Complacency kills. It is not unusual in fatality situations to hear things like, "He's gone in there to unclog that pump a hundred times". Make safety your routine.
- Anaerobic conditions present increase risk. The accumulation of manure volumes through the winter months can lead to anaerobic zones.
- Warmer weather increases risk. This makes sense since microbial populations will proliferate as temperatures increase.
- Make choices for children. Adults should take precautions to educate and protect children that live or visit a farm. This means providing kid-proof barricades to manure storage and handling areas.
- Ventilate! Keep air moving through confined spaces and animal housing areas.
- Agitation is like shaking a soda can. Agitation and movement of manure releases gas. Static manure situations can accumulate aqueous forms of gas that are released during disturbance. To demonstrate this in trainings I often shake one cola can and not shake another. I put these behind my back then hand a random can to a class participant. No one has opened the can yet.
- You can work yourself to death. Agricultural work ethics are unparalleled, however at any sign of gas exposure or dangerous gas levels clear all workers from suspect areas and take a break.
- Monitors. Gas monitors provide an alarm of invisible dangers. These can be worn on the belt. A number of vendors sell or rent reliable monitors.