WASHINGTON — The Department of Homeland Security, created to help safeguard the nation from terrorism, has faced criticism for years over its approach to tackling the ultimate fear: an attack on U.S. soil with weapons of mass destruction.

DHS’s efforts to stop nuclear, chemical and other mass-casualty attacks are scattershot and poorly coordinated, spread through an unwieldy department already difficult to manage, according to experts and some in Congress. Even DHS determined in an internal review that change was needed, congressional aides said.

That was in 2010. Now, five years later, DHS is pushing a reorganization it says will streamline anti-WMD efforts into a smooth, coordinated machine. Problem is, the new plan is coming under old criticism: that it actually leaves things uncoordinated at best.

DHS’s proposal, submitted to Congress earlier this year, would create a new chemical, biological, radiological, nuclear, and explosives office, run by a new assistant secretary. It would fully subsume two of the three main DHS entities now focused on combating WMDs. But the third – the Chemical and Biological Defense Division of DHS’s Science and Technology Directorate – would mostly stay in place. That, critics fear, would leave the same problem that hampers DHS now: different offices competing for dollars and WMD projects.

“It’s nonsensical,” said Rick Nelson, former director of the homeland security and counterterrorism program at the Center for Strategic and International Studies. “You need to have all these people located together. Doing it halfway will just create more problems. It will be disruptive.”

Added a senior DHS employee, who spoke on the condition of anonymity out of fear of retaliation for talking to the media: “If you don’t put chem-bio in there, the entire group, it’s a waste of time. What’s the sense of having a WMD directorate? It doesn’t make sense to any of us.”

DHS officials defended the plan, saying it would vastly improve a current WMD structure they described as far too diffuse. Six units at DHS headquarters in Washington work on some aspect of WMD programs, and the revamp would bring the two main ones – other than the Science and Technology Directorate – into the new WMD office. Those are DHS’s Domestic Nuclear Detection Office, which coordinates federal efforts to fight radiological and nuclear threats, and DHS’s Office of Health Affairs, which helps detect bio and chemical hazards and provides public health advice to DHS leaders.

“This reorganization … will inherently help make the nation safer. That’s what we are trying to do,” said one senior DHS official, who spoke on the condition of anonymity to describe internal deliberations. The official acknowledged the concerns about science and technology competing with the new WMD office but said management and other reforms put into place by DHS Secretary Jeh Johnson would guard against it.