Part 3 of the Exposure History Form contains questions regarding the home and surrounding environment of the patient. Dialogue with the patient should include queries about the location of the house, the house water supply, and changes in air quality.

Proximity to industrial complexes and hazardous waste sites could result in residents being exposed to toxicants in the air, water, or soil. Contamination in communities is a growing public health concern; affected persons usually seek care from their primary care providers first. If a group of people with similar symptoms and exposures is identified, and an environmental exposure problem is suspected, the clinician should call the state health department or the Agency for Toxic Substances and Disease Registry toll-free at 1-888-42-ATSDR (1-888-422-8737).

Hobbies are potential sources of toxicant exposure. For instance, model building, pottery-making, photography, silk screening, gardening, stained-glass making, and woodworking have all been associated with exposure to hazardous substances. Ask the patient what his or her hobbies are. All members in a household may be exposed to the hazardous substances from one person's hobby; small children may be especially susceptible.

Scenario 3

• 52-year-old male, retired advertising copywriter with angina
• chief complaints: headache and nausea

Scenario 3 involves another patient described in the case study on page seven. In this scenario, the patient has been retired for two years; he took early retirement from a stressful job in advertising shortly after being diagnosed with angina.

The patient's answers to the questions on the Exposure Survey (Part 1 of the form) were no: he denies exposure to metals, chemicals, fibers, dust, radiation, and physical and biologic agents; he is not aware of a connection between his symptoms and activity or time; and to his knowledge other persons are not experiencing similar symptoms.

A clue appears on Part 3 of this patient's exposure history—the patient lives two miles from an abandoned industrial site, and prevailing winds blow toward his house.

In an effort to investigate this lead, the clinician initiates the following dialogue.

The preceding dialogue has uncovered the possibility that the patient was exposed to a toxicant. Furthermore, this patient may represent an index case; others may also be exposed. To follow up this lead, the clinician contacts the state health department. The health department confirms that the site contains buried drums of methylene chloride and that it is under investigation.

An industrial hygienist employed by the health department informs the clinician that the methylene chloride can indeed exacerbate signs and symptoms of angina. The odor threshold for the chemicals is 100–300 ppm. An 8-hour exposure to 250 ppm methylene chloride can cause a COHb level of about 8%.

The laboratory reports that the patient's COHb is 6%, indicating probable exposure to methylene chloride in this nonsmoker. COHb, which forms when methylene chloride metabolizes to carbon monoxide, can be detected in blood at levels of 4% to 9% when ambient air concentrations of methylene chloride are about 220 ppm. Many factors can influence body burden, including exposure level and duration, route of exposure, physical activity, and amount of body fat.

A conference call is made, and the emergency response coordinator, a toxicologist, an industrial hygienist, and a physician discuss the patient's signs and symptoms. The clinician is given the name of the local contact person for the Association of Occupational and Environmental Clinics, who recommends a specialist to provide follow-up care for this patient.

The health department's tests of ambient air reveal no immediate crisis in the vicinity, although the levels are above background levels; test results of water samples from private wells in the area are pending. ATSDR informs the EPA regional office of the situation. EPA provides immediate assistance to the affected area, cleanup is initiated, and threats to the surrounding population are mitigated.

Progress Check