LHG hazmat on the pier is prohibited except for which of the following?

The correct choice pertains to the transfer of liquefied hazardous gases (LHG) taking place on the pier. This scenario is permissible because it is part of the operational process for handling hazardous materials, which includes transferring these substances from one location to another, typically to ensure they are delivered safely and efficiently. Regulatory guidelines recognize this activity as essential within controlled parameters, as long as appropriate safety measures and protocols are followed to mitigate risks associated with hazardous materials.

The other options relate to activities or conditions that can pose safety concerns and environmental risks, which is why they are generally prohibited in such contexts. Long-term storage of LHG on the pier can increase the likelihood of spills or accidents, which is why such practices are not allowed. Similarly, residual wastes from previous transfers can present danger; allowing these on the pier could lead to contamination and increase the hazard level for personnel and the environment. Maintenance supplies, while necessary, should not involve hazardous materials being stored on-site at a pier due to the potential for accidents or breaches of regulatory safety standards. Therefore, the transfer of LHG is the only acceptable activity in this context, consistent with safety regulations.