(Reuters) - Storm-battered Puerto Rico, with a population of 3.4 million, is still without electricity five days after Hurricane Maria struck with ferocious winds and torrential rains, the most powerful hurricane to hit the U.S. territory for nearly a century. Eighty percent of the power lines in Puerto Rico are down, the island s electricity utility PREPA said on Monday. PREPA spokesman Carlos Monroig said the utility is evaluating all of Puerto Rico s electrical infrastructure by air.  The following are responses from multinational companies with a presence in Puerto Rico on how they are dealing with the aftermath of Maria: WAL-MART STORES INC Wal-Mart spokesman Phillip Keene said:  We don t have a timetable yet on being fully operational, but we are working very hard to recover operations on the island as quickly as possible. As of this morning, hundreds of loads of water, emergency supplies and other needed resources like generators have either been delivered to the island or are on the way there. We will send trucks to open stores and those that are able to accept deliveries as soon as safely possible. No details to share on economic or operational impact.  Lisa Belot, media relations at Sprint, said:  Due to the severe damage caused by Hurricane Maria and the impact on Sprint s network, technical staff have mobilized to review the state of our sites in Puerto Rico and to expedite the reconstruction process to reestablish communication as quickly and safely as possible for all of our customers. Our first shipment has already arrived in Puerto Rico with generators and parts required for restoration, and crews of engineers and technicians from the U.S. have already joined the local team on the island. A second shipment is scheduled to arrive on Wednesday.  The company said:  We are closely monitoring our network in Puerto Rico and working to address the full effects of Hurricane Maria. Storm damage is significant across the region and commercial power is unavailable, both of which can affect our ability to provide service. And, unfortunately, some cleanup crews working in the area have accidentally damaged additional communications infrastructure.  We are coordinating with local authorities and deploying resources as rapidly as possible to assist in restoration and recovery efforts as quickly as conditions allow.  Nat lia Salom o, global corporate media relations at drugmaker and consumer Johnson & Johnson, said:  Our preliminary assessment is that our physical facilities fared well given the magnitude of the storm. We are partnering with local and federal authorities to monitor the state of the infrastructure.  While we helped our employees and campuses prepare, we continue to work with customers and our emergency aid partners to restock products and relief supplies that have been in heavy demand. Prior to the storm, we took steps to adjust our raw material and product supply flow to account for potential interruptions, and we will continue to assess the situation.  BRISTOL-MYERS SQUIBB CO         Bristol-Myers Squibb spokesman Ken Dominski said:  Puerto Rico sustained significant damage, and our primary concern is with our employees, their families and the citizens of Puerto Rico.  We have some damage to one of our three facilities, however we are executing contingency plans that we believe mitigates product supply risk as we assess the situation on the island and work to bring our operations back online. We are contacting employees to provide support in their recovery from Hurricane Maria while the Bristol-Myers Squibb Foundation is responding with a $250,000 cash donation to support emergency relief efforts.  Scott Sayres, a spokesman for Honeywell International, said the company s focus is on making sure their employees are safe.  They re still working on it ... our folks on the ground are making sure everyone s accounted for and what their needs are ... we re still assessing the facilities.  