OAKLAND — Saying he had “extreme concerns” over the mysterious dumping of charred debris from December’s fatal Ghost Ship fire in an open field, the Bay Area’s top air quality regulator said Thursday he will launch an investigation to check for asbestos and other contaminants.

The debris — everything from burned musical instruments, appliances, artwork and clothes to pieces of the building — was dumped weeks ago at the end of a path on city-owned land adjacent to a soccer field along the Martin Luther King Jr. Regional Shoreline and yards from an East Bay Regional Park District bay-front trail.

The material clearly should not have been dumped there, said Wayne Kino, director of enforcement for the Bay Area Air Quality Management District. He said the agency was never informed.

“There has to be some reporting requirements, (but) at this point, we don’t have any notifications from that site,” he said.

On Dec. 2, 36 people died in an inferno that broke out in a Fruitvale district warehouse that was being used as an unpermitted arts collective.

City officials have refused to say why the numerous large piles of debris from the Ghost Ship were dumped near the shoreline. City spokesman Harry Hamilton said debris was transported to two separate locations to allow emergency services to perform their duties. He did not say where those locations were.

A spokesman for the city public works department forwarded questions to a contracted public relations firm dealing with issues about the fire for the city. It did not reply. City Administrator Sabrina Landreth didn’t return a message.

If environmental violations are found, the city would be required to dispose of the material properly and could face fines, Kino said.

The debris could also be harmful to the nearby bay, the leader of a local environmental group said. Nearly 11 inches of rain have been recorded at the nearby Oakland International Airport since Jan. 1, according to the National Weather Service.

“Unless it’s a completely contained site, runoff from it drains somewhere,” said David Lewis, executive director of Save the Bay. “Runoff close to the bay almost definitely drains into the bay or to a creek.”

A muddy berm separates part of the debris field from a wetland. Fences surround most the area, but a portion of it is torn down, allowing access. Several former Ghost Ship residents have scoured the site and removed items.

It took firefighters and others nearly three days to remove all of the victims from the warehouse after the fire. They needed to shore up the building and break through a wall to create a second way inside. Much of the debris was hauled off-site and combed through by agents from the Bureau of Alcohol, Tobacco and Firearms searching for evidence.

A spokeswoman for the Alameda County District Attorney’s Office, which is conducting a criminal investigation of the fire, said the dumped material is not evidence. When asked how it ended up dumped in a vacant lot near the bay, Teresa Drenick responded in an email: “You may want to check with the city.”

Even in the frantic days after the fire, the air district’s strict pollution control rules applied to the disposal of debris from the building, Kino said.

The local air quality district has some of the most stringent rules over emissions and hazardous air pollutants in the nation, treating all commingled ash and debris as hazardous asbestos and enforcing strict regulations on its removal and disposal, Kino said. After mingling together with ash or grout, asbestos becomes difficult to identify and can inadvertently cause health hazards.

The building, originally built in the 1930s to be used as a milk bottling plant, could have had asbestos in the ceiling material, glue in the flooring, adhesives that use asbestos, or grout in the tiling, Kino said. They would not know the exact nature of the hazardous material until the investigation is over.

Evidence from the fire that could potentially be used in the prosecution has been secured and housed in other locations, sources have said. But experts question the logic of leaving massive amounts of other materials from the fire exposed to the elements in the vacant lot.

John DeHaan, an independent fire investigator who spent nearly three decades as a criminalist focused on fire and explosion evidence, questioned the handling of the materials and whether it was wise to dump them in an unsecured lot.

“You are supposed to keep track of this stuff so if later on there’s consideration that something in there might be evidence in how the fire started or what killed somebody you can go back to that pile and take a look,” DeHaan said.

“None of that will be defensible anymore as evidence,” he said.