The number of weeks your baby was premature: 6 weeks. Subtract the number of weeks premature from the chronological age: 20 weeks minus 6 weeks equal 14 weeks. 14 weeks is your baby's adjusted age.
The use of chemical fertilizer containing anhydrous ammonia can lead to exposure. Outdoor exposure to high levels of anhydrous ammonia can result from leaks and spills at production plants and storage facilities, and from pipelines, tank trucks, railcars, or ships and barges that transport ammonia.
A cylinder conforming to specification DOT 3A, 3A480X, or 4AA480 used exclusively for anhydrous ammonia, commercially free from corroding components, and protected externally by a suitable corrosion-resistant coating (such as paint) may be requalified every 10 years instead of every five years.