The world trade center clean up and recovery worker cohort study: respiratory health amongst cleanup workers approximately 20 months after initial exposure at the disaster site.

OBJECTIVE: Respiratory health among cleanup workers at the World Trade Center (WTC) disaster site was evaluated approximately 20 months after the initial exposure to assess the risk of lower respiratory symptoms.
METHODS: In 2003 a self-administered questionnaire requesting information about site experience, current respiratory and historical health, and smoking was sent to 4,546 workers employed at the site (response 25%), and 2103 workers who were never at the WTC (response 12%).
RESULTS: As compared with those never at the site, WTC workers were more than three times as likely to report any lower respiratory symptoms (rate ratio = 3.40, 95% confidence interval: 2.33-4.94).
CONCLUSIONS: These results suggest an impact on respiratory health related to work experience at the WTC and indicate further monitoring to address potential long-term effects.