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2.4 CASE STUDIES 2.4.1 Rhinehart Tire Fire -Winchester, VA A fire of unknown origin began on October 31, 1983 in a dump in Winchester, Virginia. This event became known as the Rhinehart Tire Fire. The dump contained approximately 5 million scrap tires over a 1.6-hectare [ha (4-acre)] site. A black smoke plume rose to 910 m (3000 ft) and extended some 48 - 80 kilometers [km (30 - 50 miles)]. On November 2, 1983, EPA requested immediate technical assistance from the National Institute for Occupational Safety and Health (NIOSH) to evaluate site safety and worker exposure to potentially hazardous emissions from the tire fire. NIOSH industrial hygienists collected air samples on November 4 and 9, 1983 (NIOSH, 1984). Because of varying meteorological conditions, it was not possible to collect air samples near the burning tires without being in the smoke plume. Analysis of the air samples taken in the plume indicated potentially hazardous levels of CO and PAHs. CO concentrations varied in the 50 to 100 parts per million (ppm) range. The NIOSH- recommended worker exposure limit, or Threshold Limit Value (TLV), for CO is 35 ppm [40 milligrams per cubic meter (mg/m:')] over a 10-hour time-weighted average (TWA). The TLV refers to airborne concentrations that a healthy adult worker may be repeatedly exposed to for up to 10 hours per day, five days per week, without adverse health effects. TLVs are guidelines and not strict standards for determining safe or unsafe conditions for occupational exposures. The NIOSH TLV is not applicable to sensitive receptors such as children and the elderly, who may suffer health effects at lower levels. Several PAH compounds were detected. Plume concentrations of PAHs are presented in Table 9 (NIOSH, 1984). The concentrations are averaged over approximately 405 minutes. No details are available concerning meteorological data and only a non- scaled sketch was presented in the report describing the monitoring location with respect to the fire area. Personal samples were also collected with personal portable sampling pumps attached to the clothing of line workers, equipment operators, and other personnel at the site. However, due to problems with the sampling and analysis, the authors concluded that the personal sampling results represented inaccurate (low) estimates of exposure. Therefore, personal sampling results are not reported here. The concentrations of lead, iron, and zinc in the plume were 11 µg/m3, 14 pg/m3, and 122 pg/m3, respectively. All other metals were present at less than 2 pg/m3. Metals were sampled at a stationary location in the plume. The sampling method employed included the use of a low-volume sampling pump (flow rate of 1.0 liter per minute) and a cellulose ester membrane filter. The analytical method was low temperature ashing nitric acid digestion followed by inductively coupled argon plasmography, atomic emission spectroscopy (although no specific method was cited, the procedures are consistent with NIOSH Method 7300). Analysis of the tire residue showed it to be extremely complex, containing thousands of individual compounds. The air space in a vial above a sample of the residue 16