For a set of 49 waste, water addition did not produce gas. Nearly all the solid waste produced a gas in contact
with hydrochloric acid in 5 min in an automated calcimeter with a volume >0.1 L of gas per kg of
waste. Since a plateau of pressure is reached only for half of the samples in 5 min, 6 h trial with calorimetric
bombs or glass flasks were done and confirmed the results. Identification of the gases by portable
probes showed that most of the tested samples emit mainly CO2. Toxic gases are emitted by four waste:
metallic dust from the aluminum industry (CO), two air pollution control residue of industrial waste incinerator
(H2S) and a halogenated solvent (organic volatile(s) compound(s)). HF has not been measured in
these trials started before the present definition of HP 12. According to the definition of HP 12, only the
H2S emission of substances with hazard statement EUH031 is accounted for. In view of the calcium content
of the two air pollution control residue, the presence of calcium sulphide (EUH031) can be assumed.
These two waste are therefore classified potentially hazardous for HP 12, from a total of 49 waste. They are
also classified as hazardous for other properties (HP 7, 10 and 14 for one of them, and HP 10 and 14 for the
other one respectively). Given these results, it can be assumed that few common household and industrial
waste will be classified hazardous only by HP 12.