The hazardous waste regulations under RCRA are written through exemptions. As a generator of hazardous waste, you are allowed to store your wastes on-site for up to 90/180/270 days WITHOUT having to obtain a RCRA permit. The time period depends on your generator status.
According to 40 CFR 262.34(b) and (f), you may obtain a 30-day extension to your storage time if you cannot meet the time limit due to “unforeseen, temporary and uncontrollable circumstances”. EPA does not define what it means by unforeseen, temporary and uncontrollable. It is reasonable to assume that delays caused by your transporters or labor strikes would fall into such category.
The extension is granted by EPA’s Regional Offices or the delegated state agencies on a case-by-case basis at their discretion. It is not a sure thing that you will get the extension. Note that if you fail to get the extension, you become a hazardous waste treatment, storage and disposal facility (TSDF) the day after your storage time expires!
So schedule your waste shipment early.