Abstract: On June 29, 1998, Employee #1, at Polymer Latex, Inc., in Fitchburg, MA, was performing a drumming operation, in which a waste solution of itaconic acid, sodium nitrite, and methanol in water was transferred from a pre-emulsion tank into polyethylene-lined fiber drums to be shipped out as hazardous waste. Employee #1 was unaware that the itaconic acid had reacted with the sodium nitrite in solution to form nitrous acid. Nitrous acid further reacted to form nitric acid in solution and nitric oxide, which was released to the atmosphere in the reactor room when he drummed off the waste solution. Employees #1 through #6 and two coworkers suffered from exposure to NOX (the common name given to a combination of nitric oxide and nitrogen dioxide) and were transported to the hospital. Employees #1 through #6 were treated for excessive methemoglobin in the blood, an adverse effect of exposure to NOX, and were released later that morning. Employee #1 was not expecting any toxic gas to develop, so no local exhaust ventilation was utilized, nor was the drumming performed in an enclosed system.