Agency for Toxic Substances and Disease Registry 
Case Studies in Environmental Medicine (CSEM) 

Taking an Exposure History
What Is Included in the Work History (Part 2) of an Exposure History Form?

Learning Objectives

Upon completion of this section, you will be able to

• identify specific questions asked in the work history and
• describe on how a seasoned clinician reveals a possible temporal relationship between patient’s symptoms and patient’s workplace.

Introduction

Despite recent declines in occupation-related injuries in the U.S., there remains a high annual incidence of work-related injuries and illnesses, with 495,000 newly reported cases of occupational illnesses and over 6000 occupation-related deaths annually. The U.S. Department of Labor documented 6.6 million injuries and illnesses in 1995 that were related to work activities. An estimated 80% of occupational and environmental-related illnesses are seen by primary care providers. The work history represents the primary tool for recognizing work - related medical injuries and diseases - (Thompson, Brodkin et al. 2000).

Part 2 of the Exposure History Form is a comprehensive inventory of hazardous exposures in the patient’s present and past occupations.

In evaluating Part 2 of the form, the clinician should note every job the patient has had, regardless of duration. Information on part-time and temporary jobs could provide clues to toxic exposure. Details of jobs may reveal exposures that are not expected based on the job titles. Asking if any processes or routines have been changed recently can be helpful. Military service may have involved toxic exposure.

Scenario 2

• 52-year-old male who owns a commercial cleaning service
• chief complaints: headache and nausea

Scenario 2 involves another instance of a 52-year-old male who is brought in, by his wife, to see his primary care physician for an evaluation.

According to the wife, he has been in excellent health until approximately one week ago, when he began staying up later and later at night. She was initially not too concerned, until he began awakening her to talk about the “revolutionary” new ideas he had about creating an international commercial cleaning service. She notes he was “full of energy” and talked rapidly about many ideas that he had. She became quite concerned when at 3:00 A.M. (European time) her husband called the manager of the rayon mill, who was in Europe, to discuss his ideas. He then began telephoning European banks in an attempt to find partners for his business venture. When his wife confronted him about the inappropriateness of his phone calls, he became enraged and accused her of purposefully attempting to sabotage his venture.

The patient complains of recurring headaches and nausea that started approximately one to two weeks ago and of recent angina attacks. This patient is the owner of a commercial cleaning service and is extremely proud to tell the clinician he performs some of the cleaning himself.

Questioning the patient extensively about the cleaning products fails to yield any suspicious exposure possibilities. Reviewing Part 2 of the Exposure History Form, the clinician notes detergents, ammonia, and cleansers.

Pursuance of Part 2, Work History, however, reveals a clue. The clinician’s investigation follows.

Sample Dialogue

Clinician: You own a commercial cleaning service?

Patient: Yes, I’ve been in business for 10 years and I’m going to be world wide. Would you like to purchase stock in my company?

Clinician: We can discuss that a little later. Do you do the cleaning yourself?

Patient: I don’t do as much as I used to. I have a crew of about six full-time employees. I do more managing than cleaning, but have been known to roll up my sleeves and pitch in when needed.

Clinician: You clean residences and commercial businesses?

Patient: Yes, I currently have 20 residential accounts and 15 commercial accounts, but have I told you that I will be international?

Clinician: Yes, you did, but right now I’d like to know about the commercial accounts that are local.

Patient: The downtown administrative offices for the school district, several realty offices downtown, and the business offices of the viscose rayon mill. I have six accounts in the Shaw Building downtown (small medical offices) and five retail stores in the Hilltop Mall, but I don’t know why you will not listen to how I will revolutionize the commercial cleaning industry. I’m in touch with people that control the world currency markets. I know this because God has spoken to me, telling me how to corner the cleaning market.

Clinician: So your headaches have been occurring for about one week now?

Have there been any changes in your routine—work or otherwise—in the last week?

Patient: I’ve worked more hours than usual over the last week. I’ve been doing a special project for the rayon mill. They built new offices. We moved all the old offices into the new building. That has entailed cleaning and moving furniture, files, books, and exhibits. It’s been tedious but I have plenty of energy. Fortunately, most of the staff members have been either out on vacation or at an international conference in Europe, so the building has been empty.

Clinician: Are any of your workers having similar symptoms?

Patient: No, nobody else has complained about feeling sick.

Clinician: What exactly do they produce at that plant?

Patient: They make viscose—transparent paper. I used to work there during summers when I was in college. It was hot, hard work. And the whole place smelled like sulfur—rotten eggs. We used wood pulp cellulose, treated it with acids and other chemicals, and made cellulose filaments. I worked on the blending, ripening, and deaeration process. You know I called the plant manager to help his business grow to international status.

Clinician: Can you smell the chemicals in the office building you’re working in?

Patient: Some days there’s a faint odor. Nothing like when I worked on the xanthating process. The business office building is on the northeast end of the complex. It’s pretty remote from the processing plant.

Clinician: So how many extra hours have you worked the past week?

Patient: Only about four to six hours more per day this past week. Also, this past weekend I put in an extra 10 hours. I had to finish setting up the exhibits. I didn’t trust the crew to handle the fragile exhibits, so I did the job myself. My crew is good but not as good as me.

Patient’s wife: Tell the doctor about the bottle you broke!

Patient: On Friday, about two weeks ago, I worked late setting up a huge model of the xanthating process. It was tedious work, and I was sort of stressed by the time constraints to get the job done. I had broken a bottle from the exhibit when I disassembled the thing. I’m really not certain that I broke the bottle; it most likely was stored improperly.

Clinician: What was in this bottle you broke?

Patient: I think it was carbon disulfide. I think I might have put the broken glass and the cleanup rags on the floor of my truck. This stuff had a sweet odor.

Clinician: How did you clean it up?

Patient: I changed into some protective clothing and a face mask because my eyes and nose burned. There wasn’t a lot to clean up because it seemed to evaporate quickly.

Clinician: Did you get any of the chemical on you?

Patient: I don’t think any got on me when the bottle fell, but I’m not certain.

Clinician: How much of the chemical was in the bottle? Did you report the accident to anyone at the plant?

Patient: The bottle was about liter size. It wasn’t full. There was only a small amount of liquid in the bottle. No, I didn’t report the accident. Frankly, I cleaned it up the way I was taught when I worked at the mill before. They know that I’m good. I helped them to become the organization they are today. I’ll just talk with the manager when he returns from Europe later this week.

Dialogue Analysis and Conclusion

The preceding conversation reveals a possible connection with the spill and this patient’s symptoms. It warrants further investigation. The results of the patient’s physical examination are normal, and the mental status exam shows symptoms and behavior that are typical of a manic episode. The patient is grandiose, irritable, has a marked decreased need for sleep, and is possibly having auditory hallucinations.

The patient identifies the chemical spilled as carbon disulfide, which is consistent with the patient’s symptoms.

After obtaining permission from the patient, the clinician calls the poison control center to obtain information on carbon disulfide.

Sample Dialogue About the Call

Clinician: My patient is a contract employee at a local textile company. In the process of his work, he broke a bottle that was labeled carbon disulfide. He didn’t report the accident and just cleaned it up himself. I am concerned that he may be experiencing health effects from the exposure. He is complaining of nausea, headache, and difficulty sleeping and appears to be exhibiting signs of agitation, grandiose delusions, and hallucinations.

Poison Control Center: It would not surprise me. Carbon disulfide is dangerous stuff. Strict industrial controls are in effect to prevent exposure. This chemical can cause nausea, headache, insomnia, agitation, mania, and hallucinations, all the symptoms your patient is currently experiencing. The acute symptoms are mild to moderate irritation of skin, eyes, and mucous membranes from liquid or concentrated vapors. Skin absorption causes headache, fatigue, unsteady gait, vertigo, hyperesthesia, central nervous system depression, garlicky breath, nausea, vomiting, diarrhea, abdominal pain, coma, convulsion, or death.

Clinician: Can you send me information on carbon disulfide?

Poison Control Center: Certainly. I’ll fax you the information on carbon disulfide right away. I suggest that you report the accident to the safety manager at the textile plant.

Dialogue Analysis and Conclusion

Consultation with the Occupational and Environmental Physician from the Poison Control Center confirms that this patient’s symptoms could indeed be caused by exposure to carbon disulfide.

The clinician orders a CBC; ECG; urinalysis; liver, kidney and thyroid function tests; blood serology; and an electrolyte panel.

The clinician received the faxed information and a Material Safety Data Sheet (MSDS) on carbon disulfide (see Appendix II) from the textile plant safety manager.

The clinician reviews the Health Hazard Data section of the MSDS, and notes all pertinent information in the patient’s medical record, along with the prior information faxed from the Poison Control Center.

Air sampling in the office in which the incident occurred reveals airborne concentrations of 0.8 parts of carbon disulfide per million parts of air (0.8 ppm). The Occupational Safety and Health Administration (OSHA) enforceable standard (permissible exposure limit or PEL) for carbon disulfide in workplace air is 20 parts per million (ppm) averaged over eight hours of exposure. The concentrations were most likely higher at the time of the incident two weeks ago. Also, the acute exposure the patient incurred at the time of the accident has continued to occur for a limited number of hours each week, while he drives with the contaminated rags and bottle in his truck.

Results of the laboratory tests on this patient are all within normal limits. Other employees at risk of exposure from this spill are also examined; none incurred acute exposure or suffered ill effects. Once the patient’s exposure ceases, he improves and experiences no further symptoms.

Key Points

• Work history is a comprehensive inventory of the patient’s occupations, employers, and current and potential exposures in the workplace.
• In evaluating patient’s work history, the clinician should note every job the patient had, regardless of duration.

Progress Check