(KRON) — Fireworks are tradition on Independence Day, but they caused some trouble on Monday night. According to the Contra Costa County Fire Protection District, some of those fireworks ignited fires.

The fire department said it responded to 11 fires in the hour after 9:00 p.m., at least three of which were started by fireworks. Another six of the fires may have been caused by fireworks.

In the week leading up to the Fourth of July, local fire departments warned of the danger of fireworks. The City of Rohnert Park made fireworks illegal due to the potential dangers of using them in drought conditions.

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Elsewhere in the country, fire agencies have been kept busy. In Fort Worth, Texas, the fire department reported grass fires every few minutes and FOX4 News reported that the city’s fireworks show ended early due to a grass fire.