WASHINGTON — Toxic exposure from combat burn pits in Iraq and Afghanistan isn’t a new topic, but veterans advocates hope it will get new attention in 2019.

Several groups — most prominently, Iraq and Afghanistan Veterans of America — in recent months have been pushing the issue back into the public spotlight, in hopes of spurring more public policy reaction from lawmakers.

The hope is that Congress and Veterans Affairs officials can move more quickly on research and support services before another generation of former military personnel starts showing grave health effects from the chemical poisoning.

In fact, much of 2018’s veterans policy on Capitol Hill revolved around Vietnam veterans’ exposure to the chemical defoliant Agent Orange during that conflict. Decades later, the substance has been linked to numerous rare cancers and other detrimental health effects, and veterans groups are still lobbying VA to expand their illness definitions to expand veteran benefits.

Younger veterans see comparisons in that fight with the burn pits. The trash fires — some small, short-time disposal areas, others massive waste burns fueled by gasoline — often contained a mix of different dangerous chemical fumes.

But because the size and composition varied from base to base, collecting hard scientific evidence on the adverse health effects has been difficult.

Advocates have pushed for expanded research and better tracking tools for veterans exposed to the fires. Lawmakers have been sympathetic but also slow to action on the issue.

Meanwhile, while health care is available to veterans facing serious consequences from toxic exposure, VA officials have been leery to extend disability benefits to those veterans without a better scientific backing.

The use of unregulated burn pits has all but disappeared for U.S. troops overseas, but the health effects won’t fade away as quickly. Advocates insist they need to remind Congress and federal officials of that fact as often as possible.