Each day an estimated 11 million workers in the United States are exposed to at least one of the hundreds of agents associated with occupational asthma, according to a report by Cox News Service.

The disease, characterized by breathing difficulties from repeated exposure to workplace allergens, is believed to contribute to 5 percent to 15 percent of all asthma cases, the Allergy and Asthma Foundation of America reports. Many cases remain undiagnosed because the symptoms are varied and one’s response to irritants is often delayed.

The signs of occupational asthma include:

  • Experiencing an onset of symptoms within months of starting a job.
  • Reacting to the use of a new industrial agent or process.
  • Symptoms improve after leaving work or clear up on weekends or holidays.
  • Symptoms worsen during certain points of production or during intense exposures to a specific particle.
  • Complaining of itchy eyes, wheezing, nasal congestion or taking frequent sick days for head or chest colds.