From 1988 to 1995 barley of 8-11% moisture content (m.c.) was stored at 32-38?C for 1-3 years on two concrete platforms (2,500 and 4,000 t, respectively) under UV-protected PVC liners 0.8 mm thick. In some cases platform floors were covered with a polyethylene liner 0.2 mm thick. Grain moisture, temperature, insect infestation, germination and some other quality parameters were measured during storage. Concentrations of oxygen (O2) and carbon dioxide (CO2) were also recorded. At the end of each storage period mold and total losses were determined. The effect on intergranular O2 and CO2 concentrations of covering the floor with a polyethylene liner was significant. With a polyethylene underliner, O2 and CO2 were 2-6% and 812%, respectively. Without it, concentrations were 6-10% and 2-4%, respectively. However, this did not have a significant influence on losses. Zearalenone (760 ppb) and ochratoxin A (1,990 ppb) were detected in samples of mold-damaged grain, and the total fungal count was 5.7 x 109/g. In sound grain, concentrations of zearalenone and ochratoxin A were zero, and the total fungal count was 1.6 x 106/g. The longer the storage, the higher both mold losses and total losses. After 1 year of storage, they were 0.16 ? 0.1% and 0.32 ? 0.06%, respectively. After 2 years of storage, losses were 0.22 and 0.52%, respectively, and after 3 years of storage mold losses and total losses reached 0.66 and 0.96%, respectively. After 1 year of storage, germination remained above 95%, and after 3 years it was above 88%. Hermetic storage under the PVC liner successfully protected the grain against insects, birds, rodents and rain. The total expenditure for both fixed and running expenses (building a concrete platform 25 m wide and 75 m long and hermetically storing 4,000 t of barley under the PVC liner) was US$4/t/l year or US$2.50/t/3 years.