Table 1 Case description and demographic data

Accidental occurrence

Six storage room workers were exposed to fumigants off gassing from shifted items in a medium sized European company importing electronic construction parts from Mexico and China. The exposures occurred three times (2010-2012), as reported by the patients. 48 hours after the first incidence a contracted industrial physician took blood samples and sent them to the clinical chemistry laboratory (Serum/EDTA blood, NaF blood) and sent samples to the commercial clinical chemistry laboratory to investigate intoxication parameters. Since no other information was provided to the laboratory, only a differential blood analysis was performed, no bromide,methyl bromide or other intoxication parameters were measured. As usual in such a case the blood samples were destroyed. Since two patients had persistent symptoms, the governmental industrial hygienist visited the company. He took air samples in the space between the delivered boxes; the laboratory analysis revealed 2.5-200 ppm residual methyl bromide. One year later, a second accident occurred involving the same employees. Ambient monitoring was performed, which showed the presence of methyl bromide and ethylene oxide in the air. Five days after the accident samples for biomonitoring (BM 2) were collected.

The time line of the three accidents in the storage room

The accidents occurred between 2010 and 2012. For the BM No. 1, the samples were taken 195 days after the first and 111 days after the second accident. For the BM No. 2, the biomonitoring samples were collected five days after the third accident; BM No 3. (follow up) was initiated 178 days after the third accident (2013).

Exposure associated job description

Exposed individuals: Patients 1-6 (aged: 32-54; 4 f, 2 m)

Patient 1 (47, f); patient 2 (32,m); patient 3 (39, f); patient 4 (41,m); patient 5 (54, f); patient 6 (38, f).

All patients worked 8 hours each working day in a storage space where patients 1,3,4,5 and 6 unloaded the delivered items on a regular basis, unpacked wooden pellets with paper boxes covered with plastic (containing with construction parts) and distributed the construction parts for the production line. Patient 2 supervised the working place.

Exposures associated symptoms

After each incident the workers (patients 1, 3, 4, 5 and 6) noticed itchy skin, very red eyes and suffered from recurrent epistaxis, headaches and acrotaxia. After the second accident four individuals (Pat. 1, 3, 4 and 5) additionally complained about paresthesia (pins and needles in the legs), dizziness, breathing difficulties and increasing irritability. After the third accident, patient 4 was on sick leave for several weeks; patients 1 and 3 developed immediate epistaxis with a severe headache.

Description of the workplace

Workplace: Medium sized company, which recently turned into a worldwide operating logistics unit with production and distribution centers, but no internal industrial hygiene unit. The 6 patients were working in a storage room. They were unloading ca. 2 overseas containers per week at the time of the incidence. According to the interviews the containers were not labeled for fumigants; No air monitoring was performed on a regular basis, though the workers sometimes perceived strange odors. The delivered production parts were packed in several boxes on wooden pellets wrapped with a plastic foil. The workers were responsible for unloading and distributing the delivered items into several separate areas on several different floors.