The spectacular "Fallen Blossoms Explosion Project" at the Philadelphia Museum of Art on Dec. 11 might have lasted only a minute, but it left behind a sooty souvenir in the form of black deposits on the museum's stone steps.

The metal scaffold supporting the giant flower in outline was fixed to the museum's east portico. The fireworks contractor, Grucci of Brookhaven, N.Y., laid down tar paper on the stone steps beneath the flower. Ironically, the protective covering had the opposite effect.

Hundreds of spectators on the east terrace were startled when, halfway through the burn, several small fires flared at the base of the flower as the fireworks ignited the tar paper. The flames, billowing dense black smoke, were quickly doused with fire extinguishers.

When the scaffolding was dismantled after the event, black stains darkened several sections of the top two or three steps. A museum spokesman said last week that the tar-paper residue would be removed with lasers or solvents, and that the cost would be covered by Grucci under the contract terms governing cleanup.

- Edward J. Sozanski