CROSS-REFERENCE TO RELATED APPLICATION
 This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/423,642 filed Dec. 16, 2010, which is fully incorporated herein by reference.
BACKGROUND OF THE INVENTION
 This invention relates to a containment bag. More particularly, the invention relates to a containment bag for use in association with, for example, drums and oil-filled equipment, so as to prevent spills or leaks.
 Federal requirements for a Spill Prevention Control and Countermeasure (SPCC) plan are contained in the Code of Federal Regulations, Title 40 (40 CFR), Parts 110 and 112. According to SPCC Guidance for Regional Inspectors:
 Mobile containers, such as drums, skids, and totes, must comply with the requirements of .sctn.112.8(c)(11) or .sctn.112.12(c)(11) according to good engineering practice. For these types of containers, the Environmental Protection Agency (EPA) inspector should verify that the secondary containment methods are appropriate. For example, an oil-filled drum positioned for use at a construction site must be equipped with secondary containment sized in accordance with .sctn.112.8(c)(11).
 Oil drums and totes, which could reasonably be expected to discharge oil into or upon navigable waters once the threshold SPCC capacity criteria has been met, are typically stored in overpacks, trays, or spill pallets to meet the secondary containment requirements. Overpacks seal drums completely, but are hard to open and close, especially by a single person. Trays and spill pallets can easily fill with rainwater, which can reduce sump capacity below the volume requirement. Trays and spill pallets also can be covered to limit rainwater accumulation, but this is an additional step that can be costly (e.g., build a roof), prone to weathering issues (e.g., lightweight covers tear or blow away), or difficult to lift (e.g., heavy, hard plastic lids).
 Known bags exist that could also be used as secondary containment. These include bulk bags, such as cubic yard bags, that are constructed out of woven polypropylene with a liquid liner. These bags, similar to overpacks, have the advantage of being United States Department of Transportation ("USDOT") or United Nations ("UN") rated for shipping. To receive these ratings, the bags must meet top-load lifting requirements. The woven polypropylene, however, has limited UV resistance, even when heavily loaded with UV stabilizer The poor UV resistance, coupled with a woven base that can be torn and cut when dragged across uneven surfaces, provides limited life in outdoor environments.
 Vinyl-coated fabric bags, specifically for spill control, exist that provide extended UV resistance. These options do not require a liquid liner, since the seams are heat sealed. Because of the heat-sealed seams, however, the bags cannot be USDOT- or UN-rated for drums or oil-filled equipment. The heat-sealed seams are not strong enough to meet top-load lifting requirements. These vinyl-coated fabric bags also do not have an abrasion-resistant base and are easily punctured on uneven surfaces, such as gravel.
 Thus, it would be advantageous to provide an improved containment bag that overcomes limitations and disadvantages of known such devices.
SUMMARY OF THE INVENTION
 In one aspect, the invention includes a containment bag having a base, a sidewall, and a lifting strap. The sidewall extends upward from the base and includes a sleeve top attached to an upper end of the sidewall opposite the base end. The sleeve top defines a bag opening. The lifting strap is attached to at least one of the sidewall and/or the sleeve top for lifting the containment bag. The containment bag may further comprise means for closing the bag opening. In addition, the containment bag may also include a disposable bag liner positionable within an interior of the sidewall.
 In another aspect, the invention includes a containment bag comprising an abrasion-resistant base, a tubular sidewall, and lifting straps. The tubular sidewall extends upward from the abrasion-resistant base. The tubular sidewall includes a sleeve top attached to an upper end of the tubular sidewall opposite the abrasion-resistant base end. The sleeve top defines a bag opening. The lifting straps are attached to the tubular sidewall and/or the sleeve top for lifting the containment bag. In addition, the containment bag may further include means for closing the bag opening. The containment bag may also further include a disposable bag liner positionable within an interior of the tubular sidewall.
 These and other aspects of the present invention will be more fully understood following a review of this specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
 FIG. 1 is a front elevation view of the containment bag in accordance with an aspect of the invention.
 FIG. 2 is an additional front elevation view of the containment bag illustrated in FIG. 1 showing a sleeve top of the containment bag and an expanded position in accordance with an aspect of the invention.
 FIG. 3 is an additional front elevation view of the containment bag illustrated in FIGS. 1 and 2 showing a means for closing the containment bag in accordance with an aspect of the invention.
 FIG. 4 is a front elevation view showing the containment bag in an open position and containing a drum positioned inside of a bag liner within the containment bag in accordance with an aspect of the invention.
 FIG. 5 is a top view of the containment bag in an open position illustrating the bag opening in accordance with an aspect of the invention.
 Referring to the figures, the invention disclosed herein is a containment bag, generally referred to by reference number 10. More specifically, the invention disclosed herein is a containment bag 10 that provides for secondary containment to prevent leakage or spillage of hazardous materials or the like. For example, the containment bag 10 may contain drums 11 filled with oil or other types of oil-filled equipment, so as to prevent any spillage or leakage of oil from reaching and contaminating the ground or water supplies. As will be appreciated from the description set forth herein, the containment bag 10 can be lifted by its own straps when full, transported on the highway as USDOT- and/or UN-rated container, sealed from precipitation, transported across rough surfaces, and stored outside for extended periods of time, even during ground-freezing conditions. It will be appreciated that the bag 10 can be a USDOT- and/or UN-rated container suitable for repeated use.
 Referring specifically to FIGS. 1-5, the containment bag 10 of the invention includes a base 12, a sidewall 14 extending generally upwardly from the base 12, and one or more lifting straps 16 for lifting the containment bag 10.
 In one aspect of the invention, the base 12 may be generally circular. In addition, the sidewall 14 of the containment bag 10 may be generally tubular. However, it will be appreciated that various shapes and configurations of the base 12 and the sidewall 14 may be provided in accordance with various aspects of the invention.
 In one aspect, the sidewall 14 includes a sleeve top portion 18 attached to or formed at an upper end 20 of the sidewall 14 generally opposite of the end of the sidewall 14 that is extending upwardly from the base 12. The sleeve top 18 in an open position (see, for example, FIG. 5) defines a bag opening 22 for inserting, for example, drums 11 or other types of equipment to be stored or contained within the containment bag 10. It will be appreciated that in accordance with various aspects of the invention the sleeve top portion 18 may be a continuous upper section of the sidewall 14, i.e. the sidewall extends from the base 12 to the opening 22, or the sleeve top 18 may be a separate piece attached to the sidewall 14.
 In one aspect of the invention, the base 12 is formed of a generally rigid material, so as to provide for an abrasion-resistant base that will withstand contact with various types of rough surfaces. For example, the base 12 may be formed of an ultra-high, molecular-weight polyethylene material that can be thermoformed into the described, generally circular base 12 having a generally flat bottom 24 with upwardly-rounded edges 26. The base 12 formed of, for example, the ultra-high, molecular-weight polyethylene provides for the desired abrasion resistance, as well as cold crack resistance.
 In another aspect of the invention, the base 12 having the bottom surface 24 and upwardly-rounded edges 26 is structured and arranged, so as to advantageously provide for spill containment should the drum 11 or other type of equipment being contained in the containment bag 10 leak or spill inside of the bag 10. To provide for the spill containment, the edges 26 of the base 12 may have a height H in the range of about 2 inches to 10 inches, and in one example, 6 inches in height.
 In another aspect of the invention, the sidewall 14 of the containment bag 10 is formed of a material, so as to provide for ultraviolet ("UV") resistance and/or water resistance. For example, the sidewall 14 may be formed of a vinyl-coated fabric material. In addition to the described UV and water resistance for the sidewall 14, the sidewall material needs to be sufficiently strong for lifting the containment bag 10 and the contents thereof. In one example, if a combined load of the containment bag 10 and the contents is greater than about 1500 pounds, an addition layer of woven fabric, such as, for example, polypropylene, can be used on an interior surface 28 of the sidewall 14 for added lifting strength. In another aspect, the sidewalls 14 may also have the seams thereof sealed over the stitching in order to provide additional water resistance.
 In another aspect, one or more of the straps 16 are attached to the sidewalls 14 in a suitable manner, so as to provide a means for lifting the containment bag 10. Depending upon the combined weight of the containment bag 10 and the contents being contained therein, various types of lifting equipment, such as, for example, forklifts or cranes, may be used for lifting the containment bag 10 onto a truck for transport for a storage space for storage. In one aspect, the lifting straps 16 are formed of, for example, a high-capacity, ultraviolet-resistant, woven polyester.
 In yet another aspect of the invention, the sleeve top 18 formed at the upper end 20 of the sidewall 14 that defines the bag opening 22 is structured and arranged, so as to provide for closing the bag opening. It will be appreciated that, in accordance with the invention, various types of means for closing the bag opening 22 may be provided. In one example, as shown in FIGS. 1-3, the sleeve top 18 may be rolled down and clipped shut using a clipping mechanism 30, so as to prevent rain water or other materials from entering the containment bag, as well as preventing the contents of the containment bag 10 from spilling or leaking through the bag opening 22. Other types of means for closing the bag opening 22 may include, for example, hook-and-loop type fasteners, e.g., Velcro.RTM., and draw strings.
 As described herein, the containment bag 10 provides for spill containment to prevent undesired spillage or leakage of materials contained therein. If additional capacity is needed for preventing such spillage or leakage from occurring, a bag liner 32 can be placed in the interior of the containment bag 10. For example, the bag liner 32 is positioned inside of the containment bag 10 adjacent the interior wall 28 of the sidewall 14. FIG. 4 illustrates a drum 11 being contained within the bag liner 32, as well as positioned inside of the containment bag 10.
 In one aspect of the invention, the bag liner 32 is disposable. The bag liner 32 may be formed of, for example, a polyolefin, such as, polyethylene or propylene. It is desired that the material for forming the bag liner 32 provides for water and/or chemical resistance to prevent leakage or spillage. In another aspect, the bag liner 32 can be coextruded for increased puncture resistance, such as, for example, a nylon core. In addition, the bag liner 32 may be constructed to provide improved seam sealing at lower cost using, for example, metallocene skins. Thus, it will be appreciated that the bag liner 32 produces clean out and contamination of the containment bag 10 once the contents, such as the drum 11, is removed and replaced.
 In another aspect of the invention, sorbents can be provided on the interior of the containment bag 10 or the liner 32, so as to further reduce the possibility of leaks or spills from within the liner 32 or the containment bag 10.
 Accordingly, it will be appreciated that the containment bag 10 of the invention provides for an improved containment bag having various advantages over known containment bag arrangements. For example, the base 12, as described herein, provides for abrasion resistance for contacting various types of rough surfaces, as well as upwardly-rounded edges 26 to further prevent spillage or leakage from occurring. In addition, the sidewalls 14 and the construction thereof as described herein provides for improved strength and durability of the containment bag 10.
 Whereas particular embodiments of this invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the invention as defined in the appended claims.