What’s in Chinese drywall? Federal environmental officials think they may have some answers: sulfur, strontium, and iron, for starters.

Recently concluded tests by the Environmental Protection Agency showed that Chinese-made drywall has high amounts of sulfur, which isn’t commonly found in U.S. drywall. Strontium levels and iron concentrations were significantly higher in the imported wallboard, which also included the presence of two organic compounds associated with acrylic paints. The compounds aren’t normally detected in U.S.-manufactured drywall.

The analysis used a small sample size that researchers say isn’t representative of all drywall products, and the research doesn’t say whether higher concentrations of elements found in Chinese drywall are to blame for corroding wires and household appliances, although other experts have suggested a correlation between sulfur and corrosion and foul-smelling odors.

Complaints about foul-smelling Chinese-made drywall first emerged in Florida homes this past January and have spread to homes in several states.

Some homeowners are also worried that the material is making them ill, prompting some to leave their homes. Actual health effects aren’t known, and the Florida health department has said there’s no evidence that gases emitted from the wallboard poses a serious health risk.

Louisiana Sen. Mary Landrieu and Florida Sen. Bill Nelson publicized the results of the EPA study on Tuesday. The senators have introduced legislation recalling and banning the imported drywall. “In the end, I think all this stuff is going to have to be ripped out,” Mr. Nelson said in a statement Tuesday.

A Senate committee holds hearings Thursday to further probe the nature of the tainted drywall. Witnesses include experts from the U.S. Centers for Disease Control and Prevention, the EPA, and the Consumer Product Safety Commission.

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