Plastic pail assembly for hazardous materials

A pail assembly comprising:

• a pail including a plastic sidewall defining in part a pail interior, a sealing bead disposed around an open top of said pail, a plastic pail floor connected to said sidewall and having a floor top surface and a floor bottom surface, and a plastic floor rib structure integrally molded on and extending generally across said floor top surface, said sidewall defining a rim foot extending down below the lowermost surface of said floor, said floor rib structure extends upward from and generally across said floor top surface, said floor being bowed inwardly at a central location thereof to resist outward deformation of said floor, said floor rib structure comprising a circular floor rib member disposed in a central location of said floor top surface and a plurality of radial floor ribs extending radially out from said circular floor rib member, the perimeter of said bowed floor connected to said sidewall by an upwardly curved connecting area and said radial floor ribs extending up said curved connecting area and partially up said sidewalls, said floor rib structure configured to resist the outward doming of said floor lid outer surface when said pail interior is subjected to a positive pressure;
• and
• a plastic lid securable in a sealed tight relationship to said sidewall of said pail at said pail open top, said lid and said pail defining a pail interior, said lid including a circular edge outer flange and a circular edge inner flange defining a sealing bead receiving area therebetween for sealing engaging said sealing bead, a lid bottom surface generally within said edge inner flange, said lid bottom surface comprising a lid rib structure extending down from and generally across said lid bottom surface and integrally formed therewith, said lid rib structure comprising a circular lid rib member disposed in a central location of said lid bottom surface and a plurality of radial lid ribs extending radially out from said circular lid rib member, said lid rib structure being bowed outwardly and configured to resist the outward doming of said lid outer surface when said pail interior is subjected to a positive pressure, said lid also including an opposite lid outer surface having a receiving channel for stably receiving the rim foot of another pail assembly stacked thereon;
• wherein said rim foot of said sidewall is adapted to engage the receiving channel on top of the lid of another pail assembly stacked therebeneath.