Respiratory Disease: Fumes

Welding
Welding is commonly performed on farms.  If proper respiratory protection  is not used, 
metal fume fever can occur. This causes a delayed viral-like syndrome similar to ODTS.  Metal 
fumes from welding galvanized steel cause the most symptoms.  

Agricultural Chemicals
Vapors from cleansers and disinfectants can cause an acute asthma-like syndrome called Reactive 
Airways Dysfunction Syndrome (RADS) that may last for 6 months or more.  This occurs in 
exposures to high levels of severe respiratory irritants without respiratory protection. Paraquat is 
a herbicide that causes irreversible pulmonary fibrosis (scarring) when inhaled or ingested.  
Providing supplemental oxygen actually increases the pulmonary damage.

Anhydrous ammonia is a very toxic chemical.  Stored under pressure in tanks it is in liquid form.  
When released into the soil or atmosphere it becomes a gas.  It is hydroscopic. Ammonia will 
freeze and draw the water from any tissue and cause severe eye injuries, burns, and 
larygo/bronchospasm.  This may lead to corneal opacities, acute respiratory distress, and 
irreversible pulmonary fibrosis (scarring).  Proper preventive practices include the use of full-face 
shields and ammonia respirator cartridges when applying or filling anhydrous ammonia and when 
exposure to the gas can occur.  Treatment of eye exposures is immediate and 
continuous flushing of the eyes for at least 15-30 minutes.  A recent development in rural 
areas is the proliferation of illicit methamphetamine labs and stealing anhydrous ammonia to 
produce methamphetamine. 

Learning Points
1.  There are many sources of toxic respiratory compounds found in agriculture.
2.  Hydrogen sulfide and ammonia are the primary animal confinement gases.
3.  Toxic concentrations of hydrogen sulfide can be generated when manure is agitated and 
     can cause death to humans and animals.
4.  Chronic exposure to agricultural organic dusts without adequate respiratory protection can 
     lead to respiratory irritation and sensitization and subsequent respiratory disease.
5.  Anhydrous ammonia can cause blindness, respiratory inflammation and scarring.