At around 8:00 a.m., a fire broke out under a fume hood in the washing area of the dry form manufacturing floor of a pharmaceutical plant. The fire alarm on the safety monitoring station triggered the sprinklers in the area. The fire was quickly extinguished. The 150 employees in the building were evacuated and the floor was shut down. Upon arriving at 8:25 a.m., the firefighters treated a technician for second-degree burns to her hands and carried out the usual checks throughout the premises. The employees were allowed to return to their posts at 9:00 a.m. The 600 l of non-contaminated firewater contained in the area and the sewage network was fed to the site’s wastewater treatment plant. The I&C system of a washing machine was damaged by the firewater.

The injured technician said that she saw a small spark ignite the alcohol wipe she was using to clean an electric screwdriver. In her panic, the burning wipe landed in a tank filled with 5 l of alcohol, which then ignited. There are two possible explanations for the source of ignition:

• an electrostatic discharge, such as a spark, due to vigorous rubbing of the partly dry wipe on the screwdriver’s insulated casing;
• unintentional powering of the screwdriver, which was still equipped with its detachable battery, that ignited the wipe.

The operator supplemented the operating procedures for cleaning with flammable liquids and enhanced the training of the workers performing cleaning operations:

• workers are reminded of the flash points of the cleaning solvents used;
• ignition source are prohibited within 2 m;
• cleaning operations involving rubbing must be performed at least 2 m away from all containers;
• workers are prohibited from using telephones and wearing watches and bracelets whilst cleaning.