# Safety-Assured Blocks
When you've manually verified an operation is safe, use `safety-assured` comment blocks to bypass checks:
```sql
-- safety-assured:start
ALTER TABLE users DROP COLUMN deprecated_column;
ALTER TABLE posts DROP COLUMN old_field;
-- safety-assured:end
```
All statements between the start and end markers are skipped by all checks — both built-in and custom.
## Multiple Blocks
```sql
-- safety-assured:start
ALTER TABLE users DROP COLUMN email;
-- safety-assured:end
-- This will be checked normally
CREATE INDEX users_email_idx ON users(email);
-- safety-assured:start
ALTER TABLE posts DROP COLUMN body;
-- safety-assured:end
```
## When to Use Safety-Assured
**Only use when you've taken proper precautions:**
1. **For DROP COLUMN:**
- Stopped reading/writing the column in application code
- Deployed those changes to production
- Verified no references remain in your codebase
2. **For other operations:**
```sql
ALTER TABLE new_table ADD COLUMN status TEXT DEFAULT 'pending';
```
## Error Handling
diesel-guard will error if blocks are mismatched:
```
Error: Unclosed 'safety-assured:start' at line 1
```
Rules:
- Blocks cannot be nested — a second `start` before `end` is an error
- Unclosed blocks are errors
- Unmatched `end` directives (without a preceding `start`) are errors
- The directives are case-insensitive